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Tracing thermal aquifers of El Chichón volcano–hydrothermal system (México) with 87Sr/86Sr, Ca/Sr and REE
... For this contribution, we revisit published chemical and isotopic datasets from the El Chichón volcano hydrothermal system (Peiffer et al., 2011), and investigate the tracing potential of 87 Sr/ 86 Sr in terms of fluid circulation through a reactive transport model. The simplified lithologic column of the volcano involves a sedimentary basement constituted of evaporites and limestones overlain by volcanic deposits (Fig. 1A). ...
... The simplified lithologic column of the volcano involves a sedimentary basement constituted of evaporites and limestones overlain by volcanic deposits (Fig. 1A). The strontium isotopic signature of most thermal springs, except one group, indicates that Sr is inherited from the volcanic horizon, while contribution from the sediments is negligible (Peiffer et al., 2011). Thus, it is quite intriguing that fluid flow through likelypermeable limestone horizon does not contribute to the Sr isotopic composition of the thermal springs. ...
... These waters are superficial non-thermal waters located all around the volcano, which circulate within the upper volcanic deposits. Their high Ca and SO 4 (Table 1) as well as REE content are interpreted to reflect the leaching of magmatic anhydrite, remnant from the 1982 eruption (Taran et al., 1998;Peiffer et al., 2011). Their composition will also be used for testing the response of the model regarding the composition of the mixing fluid. ...
The strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) is a natural tracer commonly used to determine water sources, water flow trajectories, and mixing relationships. In high-temperature hydrothermal systems, the low solubility of retrograde minerals such as calcite and anhydrite may significantly reduce the dissolved Sr concentration. Further contribution of Sr along the flow path from isotopically distinct sources will alter and potentially mask the original Sr isotopic signature of the fluid, limiting the potential of ⁸⁷Sr/⁸⁶Sr data for reconstructing fluid flow patterns. This study investigates the tracing potential of ⁸⁷Sr/⁸⁶Sr in terms of fluid circulation within the El Chichón volcano hydrothermal system. Although limestone aquifers are evidenced in the region, the ⁸⁷Sr/⁸⁶Sr signature of most thermal fluids from the volcano does not indicate any major Sr contribution from such lithologies, but rather reveals that Sr is inherited from volcanic rocks. An isotope-enabled reactive transport model is performed to investigate under which conditions a connection between the limestone and volcanic aquifers is compatible with chemical and Sr isotopic compositions of the thermal springs. Results indicate that the ⁸⁷Sr/⁸⁶Sr signature of a sedimentary fluid with moderate Sr concentration can be completely modified into a magmatic signature after interacting with Sr-rich primary minerals, such as plagioclases, within short period of times (< 1 year). Primary minerals release magmatic Sr to the fluid while secondary minerals (such as calcite) progressively precipitate and remove the initial sedimentary Sr. The El Chichón hydrothermal system hence represents a case where the ⁸⁷Sr/⁸⁶Sr of most springs does not keep any memory of the circulation through the sedimentary basement, as magmatic Sr dominates the isotopic signature. A certain analogy exists with hydrothermal fluids vented at oceanic spreading centers, whose ⁸⁷Sr/⁸⁶Sr signature departs from seawater and reflects Sr inherited from water-basalt interaction.
... Among the microcomponents, a special place is occupied by rare alkalies (Li, Rb, Cs), alkaline-earth elements (Sr, Ba), and rare-earth elements (REE), or lanthanoids, because they serve as good indicators of water-rock interaction (Peiffer et al., 2011;Kalacheva et al., 2016). The main similarities and differences in the microcomponent compositions of the two groups under study are as follows (see Table 3): ...
... More detail about the boron systematics in thermal waters can be found in (Bernard et al., 2011;Begue et al., 2017, among others). The behavior of trace elements in waters of different types is frequently treated in terms of coefficients in the distributions of elements between the host rock and the solution (see, e.g., Pokrovski et al., 2013;Peiffer et al., 2011) . The coefficients are defined as follows: ...
... However, we know of cases in which the REE concentrations differ by a few orders of magnitudes, while the respective pH values are the same. All other things being equal, the concentration of REEs increases with increasing concentration of chlorine ions in water (Peiffer et al., 2011). This effect seems to be the case here too. ...
... Среди микрокомпонентов особую роль играют редкие щелочи (Li, Rb, Cs), щелочноземельные элементы (Sr, Ba) и редкоземельные элементы (РЗЭ), или лантаноиды, поскольку они служат хорошими индикаторами взаимодействия водапорода [Peiffer et al., 2011;Kalacheva et al., 2016]. Основные сходства и различия в микрокомпонентном составе двух исследованных групп заключаются в следующем (см. ...
... Поведение микроэлементов в водах различных типов часто рассматривают в терминах коэффициентов распределения элементов между вмещающей породой и раствором (см. например, [Pokrovski et al., 2013;Peiffer et al., 2011]) . Коэффициенты распределения определяются как: ...
... Однако известны случаи, когда при равных рН концентрации РЗЭ различаются на порядки. При прочих равных условиях концентрация РЗЭ растет с увеличением концентрации хлор-ионов в воде [Peiffer et al., 2011]. По-видимому, этот эффект реализуется и в При этом рН источников вулкана Берга почти на единицу выше рН источников мыса Ключевой (см. ...
... Worldwide, there is a consensus that in central Chile, climate change will affect the dynamics of glaciers and snowpack, increasing the amount of melting in spring and early summer and reducing the amount of melting in late summer and early autumn, which is low-flow season in Mediterranean climate areas, like central Chile [3][4][5]. Thus, groundwater storage and liberation will be more important in terms of the resilience of mountain communities to climate variability, especially in mountainous areas where the presence of fractured porous rock systems produces conditions for the maintenance of minimum flow due to the liberation of groundwater [6][7][8][9]. ...
... The Nevados del Chillán volcanic complex possesses cold and hot springs distributed along its edge [15], from which it may be inferred that the volcanic complex behaves in a form similar to the systems described by [6,7]. The existence of cold and hot springs indicates the existence of at least two aquifers: a superficial one that receives its recharge by infiltration of rainwater and snowmelt discharging in cold springs and a deeper system, which is recharged from the superficial system and is in contact with the magma chamber, heating the water and producing vapor that feeds the thermal springs ( Figure 5a). ...
... At Mount Fuji in Japan, water can flow vertically through fractures, with water from different aquifer formations mixing, as established using isotopes, major ion chemistry, and multivariate statistical methods [7]. In Mexico, the hydrothermal system of El Chichón volcano was also studied using isotopes [6] and water chemistry, allowing the identification of two aquifers that make up the volcanic structure in a system that is controlled by infiltration from rainfall, water percolation, and heating and production of hydrothermal vapor. In Italy, environmental isotope techniques, hydrogeochemical analysis, and hydraulic data were used to identify recharge areas and trace groundwater flows at Mount Vulture [18]. ...
... Данные для элементов, отсутствующие в этой работе, взяты из работы [Войткевич и др., 1990] для среднего андезита. В качестве нормирующего элемента взят натрий, поскольку среди породообразующих элементов при взаимодействии вода-порода он является самым подвижным и широкo применяется для построения подобных диаграмм [Peiffer et al., 2011;и др.]. На диаграмме для нейтральных вод (см. ...
... Составы кислых вод вулкана Менделеева, таким образом, сформированы иным способом, нежели простое растворение вмещающей породы ультракислой смесью конденсата магматического пара и метеорной воды, что выражается также и в общем убывающем тренде поведения коэффициентов распределения Изотопный состав Sr и Cа/Sr отношения в термальных водах. Изотопный состав стронция в природных водах служит хорошим индикатором состава вмещающих пород водных резервуаров [Виноградов, Вакин, 1983;Пампура, Сандимирова, 1991;Peiffer et al., 2011]. В работе [Peiffer et al., 2011] отношения Ca/Sr и 87 Sr/ 86 Sr позволили различить два резервуара гидротермальной системы вулкана Эль Чичон (Мексика): более глубокий в осадочных породах и малоглубинный в вулканических породах. ...
... Изотопный состав стронция в природных водах служит хорошим индикатором состава вмещающих пород водных резервуаров [Виноградов, Вакин, 1983;Пампура, Сандимирова, 1991;Peiffer et al., 2011]. В работе [Peiffer et al., 2011] отношения Ca/Sr и 87 Sr/ 86 Sr позволили различить два резервуара гидротермальной системы вулкана Эль Чичон (Мексика): более глубокий в осадочных породах и малоглубинный в вулканических породах. Отношения Ca/Sr в исследуемых нейтральных Cl-Na и кислых Cl-SO 4 существенно различаются, в последних это отношение в 3 раза выше (табл. ...
... The data for elements that are missing in this paper were taken from ( Voitkevich et al., 1990) for average andesite. Sodium was used as the normalizing element, because it has the highest mobility among rock-forming elements during the water-rock interaction and is widely used for constructing such diagrams ( Peiffer et al., 2011, among others). The distribution coefficients are arranged in decreasing order as they are found in the Stolbovskie springs in the diagram for neutral waters (see Fig. 5a). ...
... The isotope composition of the Sr and Cа/Sr ratios in thermal waters. The isotope composition of strontium in natural water is a good indicator of the compo sition of host rocks in the respective water reservoirs ( Vinogradov and Vakin, 1983;Pampura and Sandimirova, 1991;Peiffer et al., 2011). Peiffer et al. (2011) used the Ca/Sr and 87 Sr/ 86 Sr ratios to distinguish between two reservoirs in the hydrothermal system of El Chichon Volcano, Mexico, a deeper one in sediments and a shallower one in volcanic rocks. ...
... The isotope composition of strontium in natural water is a good indicator of the compo sition of host rocks in the respective water reservoirs ( Vinogradov and Vakin, 1983;Pampura and Sandimirova, 1991;Peiffer et al., 2011). Peiffer et al. (2011) used the Ca/Sr and 87 Sr/ 86 Sr ratios to distinguish between two reservoirs in the hydrothermal system of El Chichon Volcano, Mexico, a deeper one in sediments and a shallower one in volcanic rocks. The Ca/Sr ratios are substantially different in the neutral Cl-Na and acid Cl-SO 4 waters, with the ratio being 3 times greater in the latter ( Table 5). ...
This paper reports a detailed geochemical study of thermal occurrences as observed in the edifice and on the flanks of Mendeleev Volcano, Kunashir Island in August and September 2015. We showed that three main types of thermal water are discharged there (neutral chloride sodium, acid chloride sulfate, and acid sulfate types); these waters exhibit a zonality that is typical of volcano-hydrothermal island arc systems. Spontaneous and solfataric gases have relatively low 3 Не/ 4 Не ratios, ranging between 5.4Ra and 5.6Ra, and δ 13 С-СО 2 between-4.8‰ and-3.1‰, and contain a light isotope of carbon in methane (δ 13 С ≈-40‰). Gas and isotope geothermometers yield relatively low temperatures around 200 о С. The isotope compositions in all types of water are similar to that of local meteoric water. The distribution of microcomponents varies among different types. The isotope composition of dissolved Sr varies considerably, from 0.7034 as observed in Kunashir rocks on an average to 0.7052 in coastal springs, which may have resulted from admixtures of seawater. The total hydrothermal transport rates of magmatic Сl and SO 4 , as observed for Mendeleev Volcano, are 7.8 t/d and 11.6 t/d, respectively. The natural outward transport of heat by the volcano's hydrothermal system is estimated as 21 MW.
... Primary rock dissolution releases elements in waters, whereas the precipitation of secondary minerals removes the elements from the dissolved phase. Acidic volcanic lakes are characterized by sulphate rich waters sometimes leading to oversaturation of SO 4bearing minerals (e.g., gypsum, anhydrite, alunite, jarosite) (Hikov, 2011;Peiffer et al., 2011;Varekamp, 2015). The most extreme, hyperacidic sulphate-dominated fluids might be the analogue on Earth of fluids on Mars, from which the precipitation of gypsum, jarosite, hematite is suggested, as found by the Opportunity (Rover) (Klingelh€ ofer et al., 2004;Varekamp, 2004;Varekamp, 2015). ...
... The distribution of REE in waters depends on the pH, Eh, stability of the REE-complexes, dissolution of primary rocks and the state of equilibrium between water and secondary minerals (Wood, 1990;Millero, 1992;Lewis et al., 1998;Wood, 2003;Varekamp et al., 2009;Piper and Bau, 2013;Inguaggiato et al., 2015Inguaggiato et al., , 2016Varekamp, 2015). Particularly, sulphate minerals were recognized as the solid phases possibly ruling the fate of REE in the sulphatedominated waters (Peiffer et al., 2011;Hikov, 2011;Varekamp, 2015 and references therein). Consequently, REE reflect geochemical processes in the volcano-hydrothermal system, and hence possibly changes in the volcanic-hydrothermal activity (Varekamp, 2015). ...
... The sulphate minerals alunite, jarosite, anhydrite and gypsum are common minerals precipitating in the acidic sulphatedominated waters in hydrothermal systems, as recognized in Santa Ana (El Salvador), El Chich on (Mexico) and Cophaue crater lakes (Argentina) (Gammons et al., 2005;Varekamp et al., 2009;Peiffer et al., 2011;Colvin et al., 2013;Varekamp, 2015). These sulphate minerals, especially alunite and jarosite, are considered responsible for the LREE depletion found in acidic waters (Inguaggiato et al., 2015;Varekamp, 2015). ...
The geochemical behaviour of major elements, Fe, Al, Mn, and Rare Earth Elements (REE) was investigated in the “Laguna Verde” acidic crater lake of Azufral volcano (Colombia). The cold lake water (T close to 10 °C) is sulphate-dominated, due to absorption and oxidation of H2S (pH 2.1–2.7, Eh 196–260 mV), and Na-enriched (Total Dissolved Solids 0.79 g L⁻¹). The total amount of REE dissolved in the lake ranges from 3.3 to 9.1 ppb. The REE patterns normalized to the local rocks show a Light Rare Earth Elements (LREE) depletion quite constant in the 15 samples. Similar patterns were already found in the acidic sulphate springs of Nevado del Ruiz volcano-hydrothermal system, caused by the precipitation of alunite and jarosite, absorbing LREE and hence removing them from solution. Alunite and jarosite minerals are not oversaturated at chemical-physical conditions within the lake itself, but alunite becomes oversaturated for temperatures above ≈100 °C, reigning in the underlying hydrothermal system. Water temperatures close to 75 °C were found in the northern part of the lake. Coupling the distribution of REE in lake water (LREE depleted) and the saturation indexes, we suggest that the distribution of REE in the lake water is the result of the alunite precipitation in the northern part of the lake and/or in the deeper hydrothermal system. The acidic hydrothermal fluids mobilize the REE with contents up to ≈5 orders of magnitude higher than seawater; acidic-hydrothermal systems, such as acidic crater lakes, can hence be considered potential REE “reservoirs”.
... Soon after (first observed on April 25, 1982) three lakes appeared in the crater floor that by November of that year coalesced into one (Casadevall et al., 1984). Since that time, several authors have studied El Chich on's crater-lake-system dynamics, geochemistry, and evolution (Casadevall et al., 1984;Armienta and De la Cruz-Reyna, 1995;Armienta et al., 2000Armienta et al., , 2014Taran et al., 1998;Taran and Rouwet, 2008;Tassi et al., 2003;Rouwet et al., 2004Rouwet et al., , 2008Rouwet et al., , 2009Morton-Bermea et al., 2010;Peiffer et al., 2011;Mazot et al., 2011;J acome Paz et al., 2015;Peiffer et al., 2015). ...
... Lake formation after the 1982 event was likely the combined result of groundwater infiltration from a shallow hydrothermal system and rainfall contribution (Casadevall et al., 1984). The lake water has served as an important source of information of the current state of the hydrothermal and magmatic systems of El Chich on (Armienta and De la Cruz-Reyna, 1995;Tassi et al., 2003;Taran et al., 1998, Taran andArmienta et al., 2000Armienta et al., , 2008Armienta et al., , 2014Mazot and Taran, 2009;Morton-Bermea et al., 2010;Peiffer and Taran, 2013;Peiffer et al., 2011;Rouwet, 2011;Rouwet et al., 2004Rouwet et al., , 2009). Since its formation the crater lake has never disappeared, but it has shown notable geochemical/physical changes: for example, the pH has ranged from an initial ultra-acid value of 0.56, in January 1983, to 2.57 in January 2003, 2.32 in January 2009, and 2.54, in April 2014, as reported by Armienta et al. (2014). ...
... Moreover, the lake geochemical composition has shown strong variations of the main ions over time, particularly SO 4 2À and Cl À concentrations. This variability has been related to the activity and influence of near-neutral geyser-like springs into the lake water (Rouwet et al., , 2009Peiffer et al., 2011Peiffer et al., , 2015, and to the changing input of hydrothermal waters and H 2 S-rich gases, influenced by tectonic and meteorological effects (Armienta et al., 2014). In order to assess these geochemical variations, Armienta et al. (2014) used the parameter Degree of Neutralization (DON) that measures the extent of water-rock interaction (Varekamp et al., 2000). ...
... It seems that the chemical characteristics of host rocks (felsic rocks) have a significant influence on the gull-wing chondrite- normalized REE patterns in addition to acid-sulfate nature of the thermal springs. It can be deduced from chondrite-normalized REE pattern of the rock samples observed in Japan (Akita-Yakeyama volcano) (Sanada et al., 2006), Italy (La fossa volcano) (Fulignati et al., 1999;Biddau et al., 2002), Mexico (El Chichón volcano) (Peiffer et al., 2011) and Iran (Airekan granite) (Esmaeili-Vardanjani et al., 2013) that chondrite-normalized REE patterns display gull-wing shapes (Fig. 9). The non-acid-sulfate geothermal systems with andesitic-dacitic host rocks such as Oregon geothermal field in USA (thermal springs from Cascade Range and southeast Oregon) (Wood and Shannon, 2003) also show the gull-wing chondrite-normalized REE patterns (Fig. 10). ...
... Gull-wing pattern is identified in acid-sulfate geothermal systems and alkaline and chloridedominated waters. Thus, it can be postulated that the host rock nature and water-rock interaction process play significant role in the formation of gull-wing shapes in different types of the geothermal field waters (Peiffer et al. (2011)) in El Chichon Volcano). ...
... Due to high distribution coefficient, Eu is preferentially enters in feldspar (especially plagioclase) rather than other mineral phases (Schnetzler and Philptts, 1970;Paster and Schauwecker, 1974). On the Fig. 9. Chondrite-normalized REE patterns of Taftan geothermal field andesitic-dacitic rocks (gray field) and felsic rocks from different areas of the world including Italy (Fulignati et al., 1999;Biddau et al., 2002), Japan (Sanada et al., 2006), Mexico (Peiffer et al., 2011) and Iran (Esmaeili-Vardanjani et al., 2013). Fig. 10. ...
Concentrations of rare earth elements (REEs) were determined in springs and andesitic-dacitic rocks of Taftan geothermal field. Hydrochemical results of major ions indicate that thermal springs are Na-SO4-Cl and Ca-SO4-Cl types. Concentrations of REEs are in ranges of 10-4 to 1.2 and 49 to ~62 times of chondrite for springwater and rock samples, respectively. The thermal (STS and TTS) and the cold (APS) springs with low pH values exhibit a very high REE contents (0.64 to 3.15mg/l). Saturation index indicates that Fe and Al phases can control dissolved REE concentration in FTS and PF cold springs. The speciation of REE complexes indicates dominant presence of LnSO4+ and free ion in the Taftan thermal springs. In APS cold spring with pH ~4, fluoride complexes are dominate over the free ion and sulfate species, while in PF and FTS cold springs with pH 6.4 and 7, respectively, carbonate complexes (LnCO3+) are predominant species. Chondrite-normalized pattern for the low-pH waters show very distinctive gull-wing patterns, characteristic feature of acid-sulfate geothermal systems, and are similar to those of the host rocks. Chemical characteristics of rare earth elements in spring and volcanic rock samples indicate that REEs are originated from the andesitic-dacitic host rocks. Whole-rock-normalized REE patterns and petrographic evidences show that rare earth elements leached mainly from marginal alteration of minerals and matrix decomposition in volcanic rocks. In chondrite-normalized REE patterns, significant negative Eu anomaly in the cold springs compare to the thermal and acidic springs indicates that alteration of plagioclase is more intense in the later, corresponding to increasing in temperature and acidic state of reactant water.
... It seems that the chemical characteristics of host rocks (felsic rocks) have a significant influence on the gull-wing chondrite- normalized REE patterns in addition to acid-sulfate nature of the thermal springs. It can be deduced from chondrite-normalized REE pattern of the rock samples observed in Japan (Akita-Yakeyama volcano) (Sanada et al., 2006), Italy (La fossa volcano) (Fulignati et al., 1999;Biddau et al., 2002), Mexico (El Chichón volcano) (Peiffer et al., 2011) and Iran (Airekan granite) (Esmaeili-Vardanjani et al., 2013) that chondrite-normalized REE patterns display gull-wing shapes (Fig. 9). The non-acid-sulfate geothermal systems with andesitic-dacitic host rocks such as Oregon geothermal field in USA (thermal springs from Cascade Range and southeast Oregon) (Wood and Shannon, 2003) also show the gull-wing chondrite-normalized REE patterns (Fig. 10). ...
... Gull-wing pattern is identified in acid-sulfate geothermal systems and alkaline and chloridedominated waters. Thus, it can be postulated that the host rock nature and water-rock interaction process play significant role in the formation of gull-wing shapes in different types of the geothermal field waters (Peiffer et al. (2011)) in El Chichon Volcano). ...
... Due to high distribution coefficient, Eu is preferentially enters in feldspar (especially plagioclase) rather than other mineral phases (Schnetzler and Philptts, 1970;Paster and Schauwecker, 1974). On the Fig. 9. Chondrite-normalized REE patterns of Taftan geothermal field andesitic-dacitic rocks (gray field) and felsic rocks from different areas of the world including Italy (Fulignati et al., 1999;Biddau et al., 2002), Japan (Sanada et al., 2006), Mexico (Peiffer et al., 2011) and Iran (Esmaeili-Vardanjani et al., 2013). Fig. 10. ...
Concentrations of rare earth elements (REEs) were determined in springs and andesitic–dacitic rocks of Taftan
geothermal field. Hydrochemical results of major ions indicate that thermal springs are Na-SO4-Cl and Ca-SO4-
Cl types. Concentrations of REEs are in ranges of 10−4 to 1.2 and 49 to ~62 times of chondrite for springwater
and rock samples, respectively. The thermal (STS and TTS) and the cold (APS) springswith lowpH values exhibit
a very high REE contents (0.64 to 3.15 mg/l). Saturation index indicates that Fe and Al phases can control
dissolved REE concentration in FTS and PF cold springs. The speciation of REE complexes indicates dominant
presence of LnSO4+ and free ion in the Taftan thermal springs. In APS cold spring with pH ~4, fluoride complexes are dominate over the free ion and sulfate species,while in PF and FTS cold springs with pH 6.4 and 7, respectively, carbonate complexes (LnCO3+) are predominant species. Chondrite-normalized pattern for the low-pH waters show very distinctive gull-wing patterns, characteristic feature of acid-sulfate geothermal systems, and are similar to those of the host rocks. Chemical characteristics of rare earth elements in spring and volcanic rock samples indicate that REEs are originated fromthe andesitic–dacitic host rocks.Whole-rock-normalized REE patterns
and petrographic evidences show that rare earth elements leached mainly from marginal alteration of minerals
andmatrix decomposition in volcanic rocks. In chondrite-normalized REE patterns, significant negative Eu anomaly in the cold springs compare to the thermal and acidic springs indicates that alteration of plagioclase is more intense in the later, corresponding to increasing in temperature and acidic state of reactant water.
... These authors pointed out that: (i) the concentration of REE in hydrothermal fluids is generally lower than in parental rocks, and (ii) the increase of REE concentrations is generally associated with a decrease in the pH of the fluids. The concentration of REE in geothermal fluids has been investigated in previous works (e.g., Yongliang and Yusheng, 1991;Wood and Shannon, 2003;Peiffer et al., 2011;Fowler and Zierenberg, 2015;Chudaev et al., 2017); whereas their mobility has been selectively studied in some theoretical and water-rock experiments (e.g., Migdisov and Williams-Jones, 2006;Migdisov et al., 2016;Woitischek et al., 2017;Rillard et al., 2019). The distribution and speciation of REE in acid-sulphate waters have been studied in water-rock interaction processes of geothermal systems (e.g., Lewis et al., 1998;Sanada et al., 2006;Wood, 2006;Shakeri et al., 2015). ...
... The distribution and speciation of REE in acid-sulphate waters have been studied in water-rock interaction processes of geothermal systems (e.g., Lewis et al., 1998;Sanada et al., 2006;Wood, 2006;Shakeri et al., 2015). The use of REE in geothermal systems of Mexico has been focused to the study of hydrothermal alteration in rocks (e.g., Torres-Alvarado et al., 2007;Pandarinath et al., 2008;Verma et al., 2018;Pandarinath et al., 2020;Sánchez-Córdova et al., 2020); whereas for fluids, a limited number of studies have been conducted in some hydrothermal volcanic centres of the South of Mexico (e.g., Taran et al., 2008;Peiffer et al., 2011). ...
A geochemical mapping of rare earth (REE) and other trace elements in water and rock samples of the hidden geothermal system of the Acoculco caldera was carried out. REE and other trace elements were measured at low concentrations in waters (ΣREE <50 μg/L) and rocks (ΣREE <773 μg/g), and used, for the first time, to understand the water-rock interaction processes of this geothermal system. A bimodal frequency distribution of pH was found among acidic waters (pH <3.5) that emerge from cold springs located inside the caldera, and slightly-acid to hot alkaline spring waters (pH 5 to 9.2) from outside the caldera. The geochemical modelling of REE showed that minerals containing Al³⁺, Fe, and F⁻ were the main phases that control their concentrations in acidic waters. Different degrees of REE complexation in waters located inside the Acoculco caldera (Alcaparrosa and Los Azufres) clearly showed new signatures of geothermal activity. LnSO4⁺ complexes and free ions of Ln³⁺ were identified as major species of the acidic waters of Alcaparrosa, whereas in less acidic waters of Los Azufres, LnF⁻ show an increase in their complexation percentages. The REE chondrite-normalized patterns observed in acid waters display a depletion from light-REE (LREE) to heavy-REE (HREE), and an inverse correlation between high REE concentrations and acid pH's. The REE concentration in felsic and intermediate rocks shows “gull-wing” chondrite-normalized patterns characterised by an enrichment of LREE, a negative anomaly of Eu, and depletion of HREE with a flat tendency. The present study of water-rock interaction contributed to the identification of new geochemical signatures of major and trace elements that provide new evidences of deep formation temperatures between 200 °C and 300 °C, becoming in an effective tool for finding out convincing anomalies in hidden geothermal systems.
... Gran parte de la investigación hidrológica en sistemas de montañas se ha centrado en la dinámica de nieve y glaciares, prestándose menos atención a los procesos de aguas subterráneas que alimentan a los manantiales responsables de mantener el flujo base (Viviroli et al., 2011). Sin embargo, los procesos de almacenamiento y liberación de aguas subterráneas pueden ser muy importantes en cuencas de montaña donde existen sistemas de rocas fracturadas o complejos sistemas volcánicos (Manga, 1996;Peiffer et al., 2011;Gmati, Tase, Tsujimura, & Tosaki, 2011;Andermann et al., 2012;Muñoz-Villers & McDonnell, 2012). ...
... El complejo volcánico Nevados de Chillán posee muchos manantiales fríos y termales distribuidos a lo largo de su perímetro (Naranjo et al., 2008), por lo que posible suponer que el material que forma la estructura volcánica permite la existencia de un acuífero que recibe recarga por infiltración de aguas lluvias y derretimiento de nieve, y que está en contacto con la cámara magmática del volcán, lo que calienta el agua, produciendo vapor que escapa por fallas geológicas, produciendo los manantiales de agua caliente y las fumarolas que existen alrededor del volcán. Esto es similar a los sistemas descritos por Gmati et al. (2011) y Peiffer et al. (2011, y se esquematiza en la figura 2a. ...
Water availability at Mediterranean climatic zones reaches critical levels during the dry season that is characterized by low rainfall, high water demand and that streamflow is mostly generated by snowmelt and groundwater liberation. This article presents the characterization of two groups of springs that produce most of streamflow at the upper part of the Diguillín River watershed, located at the Andean Mountains of the Region of the Biobío in Chile (36.9° S). A group is located at the headwaters of the river, in the Valle de Aguas Calientes and the second is located in a sector named Agua Bonita. For both groups of springs were characterized the hydrogeological systems that drain and the origin of water recharges, taking into account geological and geomorphological information, as well as hydrochemistry and water isotope data of water samples taken from river, springs and precipitation. The springs of the Valle de Aguas Calientes contribute with approximately 2.5 m³/s from an aquifer system located to the interior of the Volcano Chillan; the springs of Agua Bonita contribute approximately with 4.5 m³/s from a fractured rocks aquifer.
... The El Chichón fluids (Peiffer et al. 2011) show relatively flat to slightly depleted LREE patterns relative to local rocks (Fig. 8d), suggesting that near congruent dissolution of the rocks occurs. The REE patterns of the phenocrystic phases in the 1982 pumices of El Chichón are shown as well (Luhr et al. 1984) and all of these minerals are LREE enriched, with the magmatic anhydrite having the highest REE levels. ...
... Radiogenic isotope ratios in lake waters can be used to trace the sources of the fluids. Strontium isotope ratios were used in El Chichón lake to trace the incoming fluids and their origin (Peiffer et al. 2011). Stable lead isotope ratios in Copahue crater lake waters were identical to that of the rocks that make up the underlying volcano (Varekamp et al. 2006). ...
Volcanic lakes carry fluids that range from ultra acid, high TDS brines to largely meteoric fluids. Their water compositions are governed by volcanic fluid inputs, which range from almost raw, cooled volcanic gases (largely S-Cl-F-CO2 rich fluid) to more mature solutions that result from interaction of these acid fluids with volcanic rocks. Volcanic inputs can have reacted with mature protoliths (low degrees of neutralization) or with freshly intruded magma (high degrees of water rock interaction), the latter often resulting in the precipitation of secondary minerals such as alunite. The detailed chemical lake water composition is a reflection of mineral precipitation, fractionation of trace elements in the precipitated phases (such as the rare earThelements and metals in sulfides) and element vapor phase transport by the volcanic gases. Variations in lake composition result from a changing volcanic input composition or magnitude and thus are important in volcano monitoring. The lake water dynamics also impact the lake water composition over time, and variations in evaporation rate, meteoric water input and dramatic changes in input may cause changes in element concentrations and ratios related to non steady state effects. The recovery time to steady state differs strongly between open and closed lake systems. The stable isotope compositions of volcanic lake waters reflect W/R interaction (higher δ18O), degree of volcanic gas input (higher δ18O and δD), and evaporation at elevated temperatures (flat evaporation lines). Isotope ratios of other elements usually reflect the nature of the volcanic inputs or dissolved rock. Volcanic lakes can be charged with toxic elements that upon release may impact local ecosystems and agricultural land or drinking water downstream. Volcanic lakes charged with poorly soluble gases such as CO2 and methane may represent hazards of limnic eruptions. Failure of retaining walls or dams of acid lakes may cause acid floods with damage to land and livestock downstream.
... The REE abundances provide insight into water-rock interaction processes. The REE geochemistry in geothermal fluids is complex and depends on the pH, the stability of solid phases, the concentrations of anionic ligands complexing the REE and adsorption of mineral surfaces (Wood, 1990(Wood, , 2003Lewis et al., 1997, 1998, andreferences therein;Gammons et al., 2005;Bao et al., 2008;Peiffer et al., 2011). The concentration of total dissolved REE in near neutral pH waters and in seawater is low and their dissolved species are dominated by carbonate complexes (Byrne, 2002), whereas in acidic waters (pH b 3.6) carbonate and hydroxide can be considered negligible. ...
... occurs, suggesting additional processes that fractionate the REE. The strong positive Eu anomaly found in the water of Group 1a could be justified by the slow interaction of waters with Eu enriched plagioclase, as already recognized in other hydrothermal systems (Wood, 2003 and references therein;Varekamp et al., 2009;Peiffer et al., 2011). ...
The geochemical behaviour of Rare Earth Elements, Zr and Hf was investigated in the thermal
waters of Nevado del Ruiz volcano system. A wide range of pH, between 1.0 and 8.8, characterizes
these fluids. The acidic waters are sulphate dominated with different Cl/SO4 ratios. The important
role of the pH and the ionic complexes for the distribution of REE, Zr and Hf in the aqueous phase
was evidenced. The pH rules the precipitation of authigenic Fe and Al oxyhydroxides producing
changes in REE, Zr, Hf amounts and strong anomalies of Cerium. The precipitation of alunite and
jarosite removes LREE from the solution, changing the REE distribution in acidic waters.
Y-Ho and Zr-Hf (twin pairs) have different behaviour in strong acidic waters with respect to the
water with pH near-neutral. Yttrium and Ho behave as Zr and Hf in waters with pH near neutral-toneutral,
showing super-chondritic ratios. The twin pairs showed to be sensitive to the coprecipitation
and/or adsorption onto the surface of authigenic particulate (Fe-, Al-oxyhydroxides),
suggesting an enhanced scavenging of Ho and Hf with respect to Y and Zr, leading to
superchondritic values. In acidic waters, a different behaviour of twin pairs occurs with chondritic
Y/Ho ratios and sub-chondritic Zr/Hf ratios. For the first time, Zr and Hf were investigated in
natural acidic fluids to understand the behaviour of these elements in extreme acidic conditions and
different major anions chemistry. Zr/Hf molar ratio changes from 4.75 to 49.29 in water with
pH<3.6. In strong acidic waters the fractionation of Zr and Hf was recognised as function of major
anion contents (Cl and SO4), suggesting the formation of complexes leading to sub-chondritic Zr/Hf
molar ratios.
... The behavior of Sr in the Ushishir water is similar to its behavior in submarine vents and coastal Icelandic systems. A similar isotopic rock-water exchange is typical for Sr isotopes in hydrothermal environment (e.g., Peiffer et al., 2011;Peiffer et al., 2022, and references therein). Relative concentration of Ba in all thermal seawaters is low with exception of the Reykjanes well waters (Fig. 6b). ...
Ushishir volcano is located in the middle of the Kuril Arc. The Ushishir crater, a closed bay connected with the ocean by a narrow and shallow strait, is characterized by a strong hydrothermal activity. Boiling springs, hot pools, fumaroles and shallow submarine vents are manifestations of a magmatic-seawater hydrothermal system that discharges a boiling solution that is generally similar in chemical and isotopic composition to the seafloor hydrothermal fluids at different tectonic settings. The main features of the Ushishir fluids are: (1) water has close to zero δD and a large oxygen isotopic shift (6 to 9 ‰); (2) ³He/⁴He = 7.3Ra, very low CH4 and N2/Ar > 200; (3) high boron concentration (∼70 ppm); (4) a significant uptake of Ca and Sr from the host rock and Ca/Sr ratio higher than that for seawater with ⁸⁷Sr/⁸⁶Sr 0.7037–0.7039, a bit higher than that of the rock value (0.7031). The measured onshore discharge of boiling water is ∼5 kg/s; however, a large plume of the discolored seawater is released from the outer submarine slope of the volcano indicating a much higher total mass and heat output. We compare the seafloor hydrothermal fluids with boiling water of the coastal Ushishir springs and estimate the effective water/rock ratio using our data on oxygen and Sr isotopes and some trace elements. We also discuss the correctness of the application of solute and gas geothermometers for both seafloor and coastal seawater hydrothermal systems.
... 2. Обращает на себя внимание высокие содержания в источниках "Голубые озера" мышьяка (до 1.2 мг/л) и марганца (1.8 мг/л), концентрации других элементов значительно ниже. Таблица 2. Микроэлементный состав источников "Голубые озера" и "Двуглавый" (мкг/л) Редкие щелочи (Li, Rb, Cs), щелочноземельные элементы (Sr, Ba) и редкоземельные элементы (РЗЭ) служат индикаторами взаимодействия вода-порода [Peiffer et al., 2011]. Поведение редких щелочей (Li, Rb, Cs) и щелочноземельных элементов (Ca, Sr, Ba) в исследуемых источниках показано на рис. ...
Получены новые данные о химическом составе (включая микроэлементы) и расходе ультракислых кипящих источников “Голубые озера”, разгружающихся на юго-западном склоне вулкана Баранского (о. Итуруп). Показано, что катионный состав соответствует растворению 1 г вмещающих пород в 1 л воды. На сновании выполненных гидрологических и гидрохимических измерений по руслам сновных водотоков, дренирующих сольфатарные поля и источники вулкана Баранского (руч. Кипящий и р. Серная), определен общий гидротермальный сток магматических летучих Сl и S (в виде SO4) и оценена химическая эрозия постройки вулкана. Общий измеренный гидротермальный вынос Cl и SO4 в Тихий океан достигает 14 т/сут и 41 т/сут соответственно. Смешанная химическая эрозия вулканических отложений бассейна р. Серная составляет около 150 т/км2/год. Вклад руч. Кипящий в вынос растворенных породообразующих компонентов превышает 30% от общего стока, осуществляемого р. Серная в Тихий океан.
... Породные и морские соотношения по (Войткевич и др., 1990). меняемый при построении подобных диаграмм для близнейтральных вод (Peiffer et al., 2011). Ввиду отсутствия опубликованных данных по микроэлементному составу неогеновых пород о. ...
Based on the results of expeditionary studies (July 2021), geochemical features of thermal waters (natural manifestations and borehole waters) discharging near or directly on the Sea of Okhotsk and Pacific coasts of the central part of Iturup Island were considered: Reidovskie, Lososevye, Cape Konakov, Goryachie Klyuchi, Dachnye, water-recreational complex «Vannochki». The springs (with the exception of Lososevye) belong to subneutral Cl(Cl-HCO3)-Na waters with salinity less than 10 g/l. The Lososevye springs are of the weakly acidic HCO3-SO4-Ca-Na type with salinity of 3 g/l. The spontaneous gas is dominated by CO2 (Dachnye and Vannochki), N2 (Reidovskie and Cape Konakov) and CH4 (Goryachie Klyuchi). Against the background of a general extremely low content of microelements, thermal waters are enriched with boron and lithium. The springs are characterized by small (0.1 l/s) to insignificant (0.02–0.05 l/s) flow rates, while wells drilled nearby uncover horizons of pressurized waters.
... Chondrite-normalized REEs pattern (Boynton, 1985) of the rock samples observed in WWGF shows gull-wing shapes in Fig. 4. Gull-wing pattern is identified not only in acid-sulfate geothermal systems but also in alkaline and chloride-dominated waters. It can be hypothesized that fluid interaction with the nature of reservoir rock play major role in the formation of gull-wing shapes to eliminate Oddo-Harkins effects (Peiffer et al., 2011). The most acidic hot spring WYG has similar pattern of the host rocks in the WWGF with high (LREE/HREE)HR fractionation except for the absence of its Eu anomaly. ...
... Since hyperacid volcanic fluids are more aggressive with respect to near-neutral and alkaline fluids during water-rock interaction, a higher amount of rock-derived elements, including Rare Earth Elements (lanthanides + yttrium; REE), is leached and mobilized (Michard, 1989;Lewis et al., 1997;Takano et al., 2004;Varekamp et al., 2009;van Hinsberg et al., 2010;Peiffer et al., 2011;Hikov, 2015;Inguaggiato et al., 2015;Varekamp, 2015;Inguaggiato et al., 2017;van Hinsberg et al., 2017;Woitischek et al., 2017;Inguaggiato et al., 2018;Inguaggiato et al., 2020a;Inguaggiato et al., 2020b). The geochemical and economic importance of REE prompted to study them in a wide variety of environments, among which the fluids associated with volcanic areas, and especially volcanic crater lakes (Kikawada et al., 2004;Takano et al., 2004;Varekamp, 2015;van Hinsberg et al., 2017;Inguaggiato et al., 2018;Inguaggiato et al., 2020a;Inguaggiato et al., 2020b;van Hinsberg et al., 2020). ...
Decades of geochemical monitoring at active crater lakes worldwide have confirmed that variations in major elements and physico-chemical parameters are useful to detect changes in volcanic activity. However, it is still arduous to identify precursors of single phreatic eruptions. During the unrest phase of 2009–2016, at least 679 phreatic eruptions occurred at the hyperacid and hypersaline crater lake Laguna Caliente of Poás volcano (Costa Rica). In this study, we investigate the temporal variations of Rare Earth Elements (REE) dissolved in Laguna Caliente in order to 1) scrutinize if they can be used as a new geochemical tool to monitor changes of phreatic activity at hyperacid crater lakes and 2) identify the geochemical processes responsible for the variations of REE concentrations in the lake. The total concentration of REE varies from 950 to 2,773 μg kg ⁻¹ . (La/Pr) N-local rock ratios range from 0.93 to 1.35, and Light REE over Heavy REE (LREE/HREE) N-local rock ratios vary from 0.71 to 0.95. These same parameters vary in relation to significant changes in phreatic activity; in particular, the (La/Pr) N-local rock ratio increases as phreatic activity increases, while that of (LREE/HREE) N-local rock decreases when phreatic activity increases. REE concentrations and their ratios were compared with the variations of major elements and physico-chemical parameters of the lake. Calcium versus (La/Pr) N-local rock and versus (LREE/HREE) N-local rock ratios show different trends compared to the other major elements (Na, K, Mg, Al, Fe, SO 4 , and Cl). Moreover, a higher loss of Ca (up to 2,835 ppm) in lake water was found with respect to the loss of Al, K, and Na. This loss of Ca is argued to be due to gypsum precipitation, a process corroborated by the mass balance calculation simulating the precipitation of gypsum and the contemporaneous removal of REE from the lake water. The observed relations between REE, changes in phreatic activity, and the parameters commonly used for the monitoring of hyperacid volcanic lakes encourage investigating more on the temporal and cause-effect relationship between REE dynamics and changes in phreatic activity at crater lake-bearing volcanoes.
... Table 2 and Fig. 4a and b), with relatively flat patterns between Gd and Lu. Because phosphate minerals are often enriched in MREEs, the small extent of such enrichment demonstrates that phases such as apatite or alunite are slight to moderate components of the chemical weathering fluxes of REE in this system, as already recognized in other hydrothermal systems (Liu et al., 2016;Peiffer et al., 2011;Varekamp et al., 2009;Wood and Shannon, 2003 and reference therein). [Eu/Eu*] ratios >1.0 reflect the reduced conditions of fluids (Eh = −480 to −462 mV) and/or the limited water interaction with plagioclase. ...
This study examines the water-rock-gas interaction of the Los Geysers geothermal system in the northern Trans-Mexican Volcanic Belt (TMVB). Physico-chemical parameters, δ¹³C of total dissolved inorganic carbon (TDIC), and Rare Earth Elements (REE) composition on 14 thermal water discharges are reported and discussed. Waters had temperatures ranging from 40 °C to 98 °C, pH from 7.4 to 9.2, and total dissolved solids from 598 mg L⁻¹ to 992 mg L⁻¹. Signals of thermophilic biota, mainly diatom frustules, were found in the suspended particulate matter of spring waters. The range of δ¹³CTDIC was between −7.55‰ and −4.13‰ (avg. −7.10‰). Although potentially affected by secondary processes, the dissolved C species of the studied waters likely have a predominant deep, mantle-related origin. The lanthanoids concentrations (∑REE) were variable over practically one order of magnitude, with average values between 1463 pmol L⁻¹ for Ce and 9.0 pmol L⁻¹ for Lu. Post-Archean Australian Shale (PAAS)-normalized patterns showed a slight enrichment in middle lanthanides, numerically expressed as [Sm/La]N and [Sm/Yb]N, ranging from 1.43 to 2.06 and 0.84 to 2.03, respectively. We propose that the overall signature of the REE is inherited during the regional migration of the liquid and from the primary aquifer. Moreover, PHREEQC computer code was run to calculate the dominant REE complexing ligands in the geothermal system at different temperatures. Our calculations indicate that F⁻ complexes dominate over CO3 species at outlet temperatures, but oxyhydroxide complexes (REE-O2H, REE-O2–, and REE-O⁺) act as sinks after leaching from the source rock. The ¹⁴³Nd/¹⁴⁴Nd ratio of one of the studied samples was measured (0.512320 ± 0.19; εNd = −6.20 ± 0.37, 2s.e.). The conceptual model in this paper highlights a mixing waters process between geothermal waters and cold shallow waters in the Queretaro Graben.
... Arsenic concentrations have been measured in a few water and gas samples from the currently most active volcanoes in Mexico (Colima and Popocatépetl), and from the crater lake of El Chichón, the volcano producing the most devastating eruption of the 20th century in Mexico. Arsenic contents (analyzed by ICP-MS and HGAAS) were reported in the springs near Popocatépetl (up to 0.05 mg/L) and El Chichón volcanoes (up to 0.244 mg/L), and in El Chichón crater lake water (up to 0.17 mg/L) Peiffer et al., 2011;Taran et al., 2008). The enrichment factor calculated for As in El Chichón lake water suggested a volatile input (Taran et al., 2008); however, since no strong enrichment was detected, Rouwet et al. (2009a) indicated the absence of a near-surface high temperature degassing magma batch. ...
Arsenic-rich geothermal fluids are hazardous materials of global impact, affecting different environments (groundwater, surface water, seawater, sediments, soils, atmosphere) and human and animal health. They can be released naturally or through human activities. For the first time, a systematic global assessment of geothermal arsenic (As) in fluids of the six principal types of geothermal reservoirs and their environmental impact (e.g. freshwater sources used for drinking and irrigation), distinguishing between different uses (if any), was performed based on research of the geochemical characteristics and geotectonic setting of the formation of natural geothermal reservoirs worldwide. This will assist to further improve the sustainability of geothermal energy use, which can be an excellent environmental friendly renewable energy resource for electric power production and direct heat use. Arsenic in geothermal fluids (up to several tens of mg/L) originates especially in deep seated (several kilometers) reservoirs. Proper management of geothermal fluids during exploration, exploitation, use and disposal of resulting waste products through sustainable As mitigation strategies are essential. However, more research about As speciation and volatile As is necessary to fulfil this aim. Therefore As (and its principal species) needs to be included as parameter for standard analysis and monitoring program in any project using geothermal fluids from exploration to management of resulting wastes as base to define appropriate mitigation actions.
... Similarly, the Sr isotopes are known to be a strong geochemical indicator for rock-water interaction. The differences in Sr isotopic ratios in aqueous systems may also provide information about the source and mixing (Négrel et al., 1988, Négrel et al. 1989Négrel and Roy, 1998;Pennisi et al., 2006;Peiffer et al., 2011). Boron isotopes are mobile during water-rock interaction and are derived from rock or atmospheric input (Barth, 1993). ...
In this study, multi-isotopic (O, H, C, S, Sr, B, Li) compositions were used to perform geochemical characterization, determine the source and reservoir rocks, and explain the water-rock interaction mechanisms for geothermal fluids in the low-enthalpy Havza (Samsun) geothermal field (HGF) in Turkey. The geothermal water of Na-HCO3 water type has a wellhead temperature of 53°C, pH of nearly 7.7 and an EC value of 1140 µS/cm. The geothermal springs of Ca-HCO3 water type have an EC value of nearly 667 µS/cm and a temperature of nearly 26°C. The reservoir temperatures of the HGF geothermal system were calculated as 60–90°C and 108–160°C by silica and SO4-H2O oxygen isotope geothermometers, respectively. Stable isotope compositions (δ²H and δ¹⁸O) show that the geothermal well water is mixed with deeply circulated waters fed from higher elevations (∼ 830–1260 m), while the geothermal spring water is mixed with shallow cold water. The positive δ¹³C value (+3.01‰) indicates that the dissolved inorganic carbon (DIC) in the geothermal well water has no contribution from the atmospheric CO2 but originates in the metamorphic CO2 and marine limestones. However, the DIC in the geothermal springs is derived from C3 plants and silicate weathering. The values of ³⁴SCDT show that the sulfate in the geothermal waters is due to the dissolution of sulfate minerals. The values of δ¹¹B (-1.12 to +9.37 ‰) in the geothermal well and spring waters reflect both leaching of surrounding rocks and mantle-derived B. The reservoir rock may be Late Cretaceous-Permian limestones and Jurassic sandstones considering ⁸⁷Sr/⁸⁶Sr ratios (0.707108–0.707688) and δ⁷Li values (-7.44 to +6.18 ‰), whereas it might be Jurassic sandstones based on δ¹¹B values. The strontium isotope composition of the geothermal spring water indicates the mixing of deep geothermal waters and cold groundwaters.
... The mixture of these aquifers in the crater lake provides an environment that is rich in fresh and old pyroclastic deposits, high content of magmatic anhydrite, in addition to the dissolution of volcanic rocks near the surface and in lake sediments. It is also known for low pH, as a result of the surface oxidation of H 2 S present in hydrothermal vapors (Peiffer et al., 2011), high metal content (Peña-Ocaña et al., 2020) and highly reducing conditions (Taran et al., 1998). ...
El Chichón volcano is one of the most active volcanoes in Mexico. Previous studies have described its poly-extreme conditions and its bacterial composition, although the functional features of the complete microbiome have not been characterized yet. By using metabarcoding analysis, metagenomics, metabolomics and enzymology techniques, the microbiome of the crater lake was characterized in this study. New information is provided on the taxonomic and functional diversity of the representative Archaea phyla, Crenarchaeota and Euryarchaeota, as well as those that are representative of Bacteria, Thermotogales and Aquificae. With culture of microbial consortia and with the genetic information collected from the natural environment sampling, metabolic interactions were identified between prokaryotes, which can withstand multiple extreme conditions. The existence of a close relationship between the biogeochemical cycles of carbon and sulfur in an active volcano has been proposed, while the relationship in the energy metabolism of thermoacidophilic bacteria and archaea in this multi-extreme environment was biochemically revealed for the first time. These findings contribute towards understanding microbial metabolism under extreme conditions, and provide potential knowledge pertaining to "microbial dark matter", which can be applied to biotechnological processes and evolutionary studies.
... No relation can be seen for Na vs Sr (Fig. 10d) or with Cl (Fig. 10e). Peiffer et al. (2011) identified that Ca/Sr tends to present values between 60 and 220 in thermal chloride waters with a neutral pH, values that also correspond to waters that come into contact with volcanic materials. Ca/Sr varies in the present study, with that for most of the samples ranging from 89 to 227 (Fig. 10f). ...
This study was aimed at investigating the hydrogeochemical and isotopic characteristics of low-temperature hydrothermal springs in six study sites located in the eastern portion of the Trans-Mexican Volcanic Belt, in order to evaluate the source of the thermal water, rock-water interactions, and reservoir temperature. In addi-tion, based on this, possible similarities and differences among these thermal springs were explored. Samples of thermal waters (12 samples) and non-thermal waters (6 samples) were collected during dry and rainy seasons. Stable isotopes (18O, 2H) as well as major, minor, and trace ions were analyzed for, and saturation indices and reservoir temperatures were estimated. Thermal water temperatures ranged from 33 to 55◦C and the pH was slightly acid (and slightly basic in only one case). The electrical conductivity ranged widely, from 0.2 to 27 mS/ cm, although most samples had >8 mS/cm. Using a Piper diagram, three hydrochemical facies were identified: Na-Cl, Na-Ca-SO4-HCO3, and Na-HCO3. The notable minor and trace elements and ions were B, Li, As, and F
... Chondrite-normalized REE patterns of selected samples ( Figure 6) display a gull-wing shapes [52] where water-rock interaction process plays a significant role in this shape-type formation [53]. The Eu negative anomaly (the gull body) and light (La/Sm) and heavy (Gd-Lu) "wings" suggest an association with acid-sulfate systems observed elsewhere (i.e., Taupo, Vulcano, etc.) [54,55]. ...
Acid-sulfate alteration is comprised by clays, sulfate, sinter, and native sulphur minerals crystallized as neoformation products from the dissolution of primary minerals during water–rock interaction. Smectite, kaolinite, halloysite-7 Å, and opal-A occur in assemblages with alunite. Smectite represents a mechanical mixture between two (propylitic and acid-sulfate) alteration types. High amounts of high-field strength elements (HFSE) and rare earth elements (REE) were measured in acid-sulfate rocks. The Nb vs. Ta and Zr vs. Hf show a positive trend and widely scattered relationships, suggesting a large fractionation during acid-sulfate alteration. Higher ΣREE amounts (up to 934.5 ppm) were found in clay-sulfate assemblages and lower ΣREE amounts in sinter (opal-A ± sulfate, 169.05 ppm) than fresh rocks (up to 751.2 ppm). The acid-sulfate rocks reveal a distinctive gull-wing chondrite-normalized pattern with a negative Eu anomaly and light- and heavy-REE “wings” similar to the gull-wing pattern of fresh rocks. The Eu/Eu* shows a large fractionation of acid sulfate rocks from 0.16 to 0.78 with respect to fresh trachyte products (0.10–0.38). The variation of (La/Sm)N and (La/Yb)N ratios show a large fractionation of light-REE and heavy-REE. The Y vs. Dy and Y vs. Ho show a very good positive correlation coefficient and a large Y fractionation in acid-sulfate rocks with respect to fresh trachyte rocks.
... and for the Agua Salada springs on El Chichon volcano (δ 34 S-SO 4 = +5.3‰, Peiffer et al., 2011). These data are shown in Table 1. ...
This paper deals mainly with acidic sulphate-chloride (ASC) waters that are discharged at volcanic edifices, generally, not associated with crater lakes. Geographically, the largest number of such manifestations were found on Japanese and Kuril Islands. These waters form by: (1) condensation of magmatic vapor under shallow conditions and/or (2) dissolution of magmatic gases in underground waters; (3) near-surface mixing of steam-heated sulphate waters with sodium-chloride waters of deeper formation; (4) interaction of sodium chloride waters with the rocks undergone by argillic and advanced-argillic alteration, including hydrolysis of elemental sulfur; (5) a combination of several of the listed processes. Criteria to assess the nature of such waters using their chemical and isotopic composition are based on the relative abundances of major species and trends in isotopic compositions generally controlling by mixing of magmatic-host rock-meteoric endmembers. An overview of available data on temporal chemical variations of such waters shows that usually volcanic activity is marked by an increase in the SO4/Cl ratio during or after the eruptive event. The response on the volcanic activity depends on hydrogeological conditions that control the appearance of the ASC springs.
... El complejo volcánico Nevados de Chillán posee muchas vertientes frías y termales distribuidas a lo largo de su perímetro, por lo que es plausible suponer que, desde el punto de vista de los recursos hídricos, el complejo se comporta en la forma de un sistema acuífero similar a los descritos por Gmati et al. (2011) y Peiffer et al. (2011. Es decir, correspondería a un acuífero superficial que recibe recarga por infiltración de aguas lluvias y derretimiento de nieve, que, a su vez, recarga a un acuífero más profundo que está en contacto con la cámara magmática del volcán, lo que calienta el agua produciendo vapor que escapa por fallas geológicas, produciendo las vertientes de agua caliente y las fumarolas (figura 8). ...
... El complejo volcánico Nevados de Chillán posee muchas vertientes frías y termales distribuidas a lo largo de su perímetro, por lo que es plausible suponer que, desde el punto de vista de los recursos hídricos, el complejo se comporta en la forma de un sistema acuífero similar a los descritos por Gmati et al. (2011) y Peiffer et al. (2011. Es decir, correspondería a un acuífero superficial que recibe recarga por infiltración de aguas lluvias y derretimiento de nieve, que, a su vez, recarga a un acuífero más profundo que está en contacto con la cámara magmática del volcán, lo que calienta el agua produciendo vapor que escapa por fallas geológicas, produciendo las vertientes de agua caliente y las fumarolas (figura 8). ...
... Por lo general, los sistemas fracturados están influenciados por procesos volcánicos que son más complejos, debido a la heterogeneidad geológica del acuífero de roca fracturada. Algunas áreas montañosas están altamente influenciadas por procesos volcánicos; por ejemplo, la cuenca alta del río Diguillín en Chile (Dixon et al., 1999;Naranjo, Gilbert, & Sparks, 2008) o el área influenciada por el volcán El Chichón en México (Peiffer et al., 2011), entre otros. Los depósitos volcánicos están compuestos por formaciones fracturadas y permeables que favorecen las interacciones entre aguas superficiales y subterráneas (Arumí, Rivera, Muñoz, & Billib, 2012). ...
En la zona centro-sur de Chile, el río Renegado, durante la época de
estiaje presenta un comportamiento irregular, con tramos secos y de
alto caudal, intercalados a lo largo del río al mismo tiempo. Este estudio tiene por objetivo identificar interacciones entre aguas superficiales y subterráneas que permitan explicar dicho comportamiento. Mediante una campaña de medición de caudal a lo largo del río, un análisis de las condiciones geológicas de la cuenca y el uso de un modelo numérico de flujo de agua subterránea se describen y representan las interacciones entre el nivel freático y el río. Como resultado, se identifica que la combinación particular de topografía y geología dada por la naturaleza volcánica de la cuenca lleva al río a ganar y perder aguas superficiales a lo largo de éste. Se recomienda analizar la interacción de agua superficial y subterránea para abordar estudios de diseño hidrológico y la gestión del agua en sistemas volcánicos con características similares.
... The elevation difference between the two flanks, which is about 1000 m, causes the thermal fluid flow to divert towards the Mexican flank, so leading to the discharge of predominantly meteoric water infiltrating at shallow depth towards the Guatemalan flank. This mass flow behaviour has already been observed by Peiffer et al. (2011) for El Chichón volcano and by Byrdina et al. (2013) at Ticsani and Ubinas volcanoes. ...
Mexico is the world's sixth-largest geothermal energy producer. To pursue its transition to renewable energy, other potential geothermal areas are under exploration. The Tacaná hydrothermal system is one of them. In this work, we developed a preliminary 2D numerical mass and heat flow model of the natural state of the Tacaná volcano in order to gain insight into fluid and rock properties at depth. A comprehensive set of simulations was performed involving various rock permeabilities, geometries, and upper and basal boundary conditions until the simulated data matched the measured data, including spring and fumarole temperatures at the surface and thermal spring discharge. Simulation results show that the temperature structure and the phase distribution at depth are partly controlled by the permeability distribution inside the volcano together with a low topography-driven downflow and the absence of elevated fluid pressures at shallow levels. The low topography-driven recharge may be related to a low-permeability layer, whereas low fluid pressures most probably related to a relatively deep water table. The deep thermal fluid source must be connected to the San Antonio fumarolic field by a high-permeability conduit to enhance the fluid upflow and the development of a boiling zone in the uppermost part of the cone. Furthermore, our results suggest that the (almost) total absence of hydrothermal manifestation in the NE part (Guatemala) of the volcano is controlled by the tilting of the basement rocks. Our model will be used as initial conditions for the modelling of several geothermal exploitation scenarios in future work.
... Table 3. A number of academics have tried to apply these elements concentration for investigating origin and formation condition of natural cold and thermal waters (e.g., Goguel, 1983;Giggenbach, 1991;Arsanova, 1974;Peiffer et al., 2011). The main problem is a large variability in concentrations of these elements in any type of host rocks which is difficult to interpret. ...
Thermal springs of the Bazman geothermal field, 27 km south of the Holocene Bazman volcano caldera in Makran continental margin, SE Iran, were studied for the first time. New data on major components, selected trace elements (Li, Rb, Cs, Ba, Sr, Fe, Al), water isotopic composition (H, O and S), chemical and isotopic (δ¹³C of CO2 and CH4, ³He/⁴He and ⁴⁰Ar/³⁶Ar) composition of dissolved and bubbling gases from the hottest vents are presented. Four groups of springs with temperature range of 27–44 °C discharge Na-Cl waters with total dissolved solids (TDS) of ∼800 to ∼7000 mg/L from different aquifers composed of diverse type of rocks including granites and limestone. Only the hottest and most saline springs of the Bazman field with low bicarbonate are close to equilibrium with surrounding rocks whereas the others discharge immature waters. Geothermometry based on SiO2 concentrations, Na-K and Na-K-Ca-Mg systems shows low equilibrium temperatures of up to 130 °C, consist with the temperatures estimated by alumino-silicate minerals saturation indices. The water isotopic composition (δ¹⁸O and δD) indicates meteoric origin with a small oxygen isotopic shift measured in the saline waters. The δ³⁴S values of SO4 indicate influence of gypsum and anhydrite dissolution from the host rock. Dissolved and free gases are N2-rich (>95 vol.%) with a high He content (0.5 vol.%). A biogenic origin may be suggested for CH4 and CO2 based on their carbon isotopic characteristics (−62‰ and −13‰ vs. V-PDB, respectively). The R/Ra value of 0.5 indicates a contribution of about 6 % of He from the mantle. It is suggested that the Bazman thermal waters are heated at considerable depth (4−5 km) in a deep fault system most probably by the regional heat flow according to the local geothermal gradient.
... Strontium isotopes are powerful geochemical tracers and have in- creasingly been applied to a broad range of hydrologic systems for constraining water sources and water mixing processes (e.g. Åberg, 1995;Capo et al., 1998;Semhi et al., 2000;Frost et al., 2002;Frost and Toner, 2004;Négrel and Pauwels, 2004;Négrel et al., 2007;Brenot et al., 2008;Tichomirowa et al., 2010;Peiffer et al., 2011;Zieliński et al., 2016) and/or assessing water-rock interactions, flow paths and weathering rates (e.g. Palmer and Edmond, 1992;Bullen et al., 1996;McNutt, 2000;Shand et al., 2009;Bataille and Bowen, 2012;Brennan et al., 2014). ...
This study presents major and trace element data and ⁸⁷Sr/⁸⁶Sr ratios for surface waters from a small watershed draining the Aljustrel sulphide mining area (South Portugal). The watershed is located in a geologically complex area comprising two main compartments: the northern compartment is dominated by Cenozoic formations and does not bear any mining activity, whilst the southern compartment is underlain by rocks from both the Cenozoic sedimentary cover and the mineralized sequences of the Variscan Paleozoic basement of the South Portuguese Zone. Based on the available geochemical and isotopic data, the analysed water samples can be roughly divided into five main groups: (a) group 1 corresponds to AMD-contaminated water drainages from the southern part of the catchment, showing pH < 4.0, high dissolved sulphate and heavy metal/metalloid contents and ⁸⁷Sr/⁸⁶Sr ratios ranging from 0.7101 to 0.7126; (b) group 2 is represented by unpolluted stream waters from the northern compartment, having pH > 8, marked depletions in SO4 and heavy metals and displaying Sr isotopic compositions similar to rainwater (⁸⁷Sr/⁸⁶Sr = 0.7097–0.7098); (c) group 3 includes mixed-type stream waters with pH and elemental/isotopic signatures intermediate between those of groups 1 and 2; (d) group 4 comprises the samples collected at two lime-treated water dams from the mining area, that are clearly distinguished from the impacted waters of group 1 by their elevated Ca, Mg and Sr concentrations and low ⁸⁷Sr/⁸⁶Sr ratios (⁸⁷Sr/⁸⁶Sr = 0.7085–0.7091); (e) group 5 includes clean waters from two dams located upstream of the ore processing site, which are dominantly supplied by direct precipitation and surface runoff and have pH > 6, very low SO4 and metal concentrations and ⁸⁷Sr/⁸⁶Sr ratios varying between 0.7094 and 0.7108. Variations in the ⁸⁷Sr/⁸⁶Sr ratios and Sr concentrations of the analysed waters are attributed to mixing of two main end-members: atmospheric meteoric waters (local rainfall/runoff) with low Sr contents and ⁸⁷Sr/⁸⁶Sr ratios ≈ 0.7095 and more radiogenic waters derived from the Aljustrel mining area. The highly radiogenic signatures of the southern tributaries appear to have been controlled by weathering of plagioclase from the acid volcanic rocks of the Paleozoic basement, enhanced by mining activities (pyrite oxidation), although released strontium from gangue carbonates could have locally contributed to the fluctuations of Sr contents and ⁸⁷Sr/⁸⁶Sr ratios observed in some of these water samples. By contrast, the low ⁸⁷Sr/⁸⁶Sr ratios and relatively high Sr (Cl and Na) concentrations shown by the surface waters draining the northern compartment suggest that these tributaries correspond to meteoric waters that have gained Cl, Na and Sr through wash-out of Cenozoic deposits containing finely disseminated halite layers. Finally, the decrease in the ⁸⁷Sr/⁸⁶Sr ratios and elevation of Sr contents observed in the samples from the lime-treated water dams support the involvement of an anthropogenic source of Sr with ⁸⁷Sr/⁸⁶Sr ratios lower than that of rainfall.
... A similar distribution is also characteristic for the thermal waters that are discharged beyond the boundaries of the Nizhne Koshelev field. The positive Eu anomaly possibly results from the presence in the aquifer rocks of mineral phases that are rich in this element, as well as possibly pro viding evidence of a more highly reducing environment at the source of these waters (Wood, 2003;Peiffer et al., 2011). ...
... Strontium isotopes are widely applied to study waterrock interactions processes because their signature in groundwater reflects the 87 Sr/ 86 Sr of minerals interested by aquifer rock leaching. There has been extensive use of the 87 Sr/ 86 Sr in various aspects as for studying the flow path of waters as well as mixing phenomena between waters having distinct 87 Sr/ 86 Sr (Dotsika et al. 2010;Peiffer et al. 2011). Groundwater acquires dissolved Sr: (1) in its recharge area, through infiltration and percolation processes; (2) along its flow path, through dissolution or ion exchange with minerals. ...
Discharge areas of carbonate fractured and karstified aquifers are a sensitive system of great interest, where frequently groundwater resources are tapped for drinking water supply. In geological settings affected by recent and/or active tectonics, mixing between fresh water coming from recharge areas and groundwater from deeper circuits, influenced by raising fluids, influences hydrogeochemistry. Surveys on major ions, trace elements and stable isotopes have been performed in the San Vittorino Plain (Central Italy), where the major source of drinking water for Rome is located (Peschiera Springs, mean discharge 18 m3 s−1, half of them tapped). Results of 21 springs revealed different contribution from recharge areas and deep flow paths, by increasing salinity and ion content, with particular references to Ca2+, HCO3− and SO42−. Three main groups, respectively, related to fresh waters from recharge areas, groundwater from deep contribution and a mixing group between them, have been identified. Water stable isotopes allow to identify the common origin from rainfall and a very steady contribution with seasons and year, due to the huge extent of recharge area (>1000 km2). Saturation Indexes gave insight on the contribution of deep fluids, mainly CO2 and H2S, which turned groundwater to undersaturated conditions, facilitating rock dissolution. By PHREEQC software, the mixing between two considered end-members has been simulated, evaluating about 25% of deep contribution in the basal springs of San Vittorino Plain. Chemistry of Peschiera spring reveals a very limited percentage of deep flow paths (10%), which can lead to slight hydrochemistry changes even in possible drought conditions, when discharge can decrease until 15 m3 s−1.
... Similarly the isotopic composition of strontium ( 87 Sr/ 86 Sr) provides information on flow paths and mixing of waters because the strontium isotopes directly reflect the various source rocks (e.g. Boschetti et al., 2005;Dotsika et al., 2010;Lee et al., 2011;Negrel et al., 1999;Peiffer et al., 2011;Pennisi et al., 2006). Boron stable isotope studies are applied in geothermal exploration, because boron is highly incompatible during water-rock interaction and incorporation of boron into secondary minerals fractionates its isotopes (e.g. ...
... Схожее распределение харак терно и для термальных вод, разгружающихся за пределами Нижнекошелевского поля. Положи тельная Eu аномалия в воде является, возможно, следствием присутствия в водовмещающих породах минеральных фаз, обогащенных данным элемен том, а также может свидетельствовать, о более вос становительной обстановке формирования этих вод [Wood, 2003;Peiffer et al., 2011]. ...
... рис. 4а), а самые низкие -для нейтральных, низко минерализованных термаль ных вод, разгружающихся ниже Нижнекошелев [Wood, 2003;Peiffer et al., 2011]. Изотопный состав стронция ( 87 Sr/ 86 Sr). ...
New data are presented on the geochemistry of thermal waters in the Koshelev volcanic massif in southern Kamchatka. We discuss the conditions for the generation of thermal waters, possible variants of thermal and deep-seated material supply for the Koshelev hydrothermal system, and propose a conceptual model for the system.
... More than 40 trace elements and a full set of REE were analyzed in waters of the Yurievskie springs and pools from fumarolic fields of Ebeko (Table 4). Enrichment factor of element i, F i , were obtained by normalizing the concentration of element, E i , to Mg, F i = (E i /Mg) w / (E i /Mg) r , where subscripts w and r correspond to water and rock, respectively, the ultra-acidic waters of Yurievskie springs show a pattern similar to other volcano-hydrothermal systems and crater lakes, such as Keli Mutu and Kawa Ijen crater lakes in Indonesia (Pasternack and Varekamp, 1994;Delmelle et al., 2000), El Chichon acid springs in Mexico (Taran et al., 2008;Peiffer et al., 2011) and Shiashkotan volcanic field, Russia (Kalacheva et al., 2015). The composition of rocks is a mean value of andesitic rocks of Paramushir Island (Avdeiko et al, 1992;Martynov et al., 2010). ...
El Chichón is the northernmost and youngest volcano of the modern Chiapanecan volcanic arc and is responsible for the deadliest volcanic disaster in Mexico's modern history. Forty years after the eruption, there are still uncertainties in the subsurface architecture of the volcano and its basement. Based on this, we performed aeromagnetic data analyses using reduction–transformation techniques, spectral analysis, and forward modeling to delineate the magnetic rock–strata and to image the boundaries of the magmatic reservoir or regions of molten rock. Results show that the magnetic alignments identified correlate well with the local geological features. Our preferred interpretation of the estimated Curie point depth is as a region of mush composed of crystals and molten rock below the volcano (4.77 km), depicting the transitional sector to a deeper magma reservoir. We compute values of 101.57 °C km⁻¹ and 253 mW⋅m⁻² for the geothermal gradient and conductive heat flux, respectively. In addition, we identify two complementary aquifer formations representing the shallow−local and deeper−regional aquifer units using geomorphology, topographic, and stratigraphic characteristics. The magnetic anomalies analyzed and the identification of aquifer units in this study provide new detailed information about the geological, geophysical, and hydrogeological conceptual models of the El Chichón geothermal system.
We have obtained new data on the chemical composition (including trace elements) and discharge of the Golubye Ozera ultra acid boiling springs which emit water on the southwestern slope of Baransky Volcano, Iturup Island. It is shown that the cation composition corresponds to solution of 1 g host rock and 1 L water. We carried out hydrologic and hydrochemical measurements to find the total hydrothermal release of magmatic volatiles Сl and S (in the form SO4) along the beds of the main streams that drain the solfataric fields and springs of Baransky Volcano (Kipyashchy Creek and Sernaya River) and estimated the chemical erosion affecting the volcanic edifice. The total measured hydrothermal discharge of Cl and SO4 into the Pacific Ocean reaches 14 t/d and 41 t/d, respectively. The mixed chemical erosion affecting the volcanic deposits in the Sernaya R. basin is about 150 t/km²/yr. The contribution of Kipyashchy Creek into the discharge of dissolved rock-forming components is above 30% of total discharge into the Pacific Ocean on the part of the Sernaya River.
Wells up to 3000 m deep at the foot of the active volcanoes Koryaksky and Avachinsky within the Avachinsky Depression revealed a basin of saline waters (up to 22 g/l), methane-rich gas (CH4 up to 75 vol% in dry gas) with a temperature up to about 70 °C in the western part of the explored area (Ketkino Field) and colder ones - to the east, closer to the Pacific coast. This article presents data on the chemical composition including trace elements, and isotopic compositions of these waters that include δD and δ¹⁸O of waters, ⁸⁷Sr/⁸⁶Sr of the dissolved Sr, ³He/⁴He, δ¹³C of CH4 and CO2 in gases, and δ³⁴S of the dissolved H2S and SO4. The composition of the waters is sodium chloride, with very low contents of sulfate and magnesium in waters of the western section of the basin, high calcium (up to 960 ppm), and unusually high concentrations of strontium (up to 54 ppm). The N2/Ar ratio is generally 2–3 times higher than in the air, i.e. non-atmospheric nitrogen is present. A distinctive geochemical feature of the basin is the significant difference between δ¹³C–CH4 and ⁸⁷Sr/⁸⁶Sr in the thermal Ketkino fluids comparing to colder fluids of other parts of the basin, despite the practically identical composition of waters and gases. Possible scenarios of water-rock interaction responsible for the chemical composition of waters are discussed.
Saline waters (up to 22 g/l) were tapped by deep (to 3000 m) wells at the foot of active volcanoes Avachinsky and Koryaksky, within Avachinsky depression. Temperature of waters was ~ 60°C in the western part and cold in the eastern part, closer to the Pacific coast. In this paper we present the literature and our own data on chemical and isotopic composition of these waters. The waters are of the Na-Cl type with extremely low abundances of sulfate and magnesium, high concentration of calcium and surprisingly high concentration of strontium. The waters contain about 50 ml/l of gas where methane and nitrogen are main components (~ 70 vol% and 30 vol%, respectively) and also presents H2S (~ 30 ml/l) and very low concentrations of CO2 (< 0.5 vol%). The N2/Ar ratio, as a rule, is higher than the air ratio, i.e., the non-atmospheric nitrogen presents. We discuss the possible options of the water-rock interaction, responsible for the chemical composition of waters, and offer a conceptual model of the proposed basin of mineral waters that includes the distribution of deep temperatures, the location of the possible sources of heat mineralized solutions.
Geothermal fields distributed in the southern Tibet Plateau rifts such as Yangbajing - Dangxiong basin, and the Yaluzangbu suture are characterized by intensive hydrothermal activity and high enrichment of trace elements (e.g., Li, Rb, Cs, B and Br) in geothermal springs. However, the origin of these elements and their enrichment mechanisms in those geothermal waters remain unclear. This study presents data for the enriched elements, incompatible elements, and B and Sr isotopes, in the geothermal water in the Tibetan Plateau and compares them with some typical geothermal fields worldwide, in an attempt to provide new insights into the origin and mechanism of the enrichment of these trace elements. The results indicate that all geothermal water samples from the Tibetan Plateau show more negative δ¹¹B values than those from local precipitation and rivers. Considering the wide existence of a high-conductivity zone in the middle or even upper-crust interpreted to correspond to re-melt magmatic fluids in the Tibet, the main sources of the typical chemical composition of geothermal waters in the Tibetan Plateau can be classified into two main types: residual magmatic fluids derived from crustal partial remelting and deep circulated groundwater modified by water–rock interactions. In particular, the possible source of magmatic fluids may play a more significant role for special geochemical compositions of geothermal water in the Tibet. Such resources are beneficial for the development and utilization of the geothermal water itself and also serve as a stable source for feeding the salt lake resources.
B-Sr isotopes and selected trace elements were used to assess the multiphase fluid flow path in the Changbaishan volcanic two-phase geothermal system (Jilin, Northeast China). The Ca/Sr ratio can distinguish volcanic and sedimentary rock reservoirs, while clastic and carbonate rocks need to be combined with the Sr/Na ratio. The lithology of the reservoir can be further ensured through contrastive water and rock 87Sr/86Sr ratios. Additionally, with caution in determining chemical composition of different endmembers, the B-Sr isotope model is useful in tracing the steam-heated/condensate water (group 1, which can be further divided into Group 1–1 and Group 1–2, according to the reservoir lithology), karst water (group 2) and residual water (group 3) flow paths. From the geochemistry and isotopes in the Changbaishan geothermal system, we infer that (1) basalt, clastic and carbonate rocks are the three main reservoirs and (2) the geochemical character of thermal waters is the result of four fluid-participating endmembers: surface water (TC), near-surface water (EM-2), residual sea water (EM-4) and vapor separated from deep sea water (EM-5). In addition, based on the B-Sr isotope model, we also established a simple conceptual model: group 1–1 represents mixing between EM-5 and TC after fluid-basalt interaction; group 1–2 indicates mixing EM-2 with EM-5 and experienced a Mesozoic granite leaching process; and group 3 is the result of EM-2 mixing with EM-4 after interaction with carbonates. The formation of Group 2 is mainly related to karst water, which is directly affected by hot magmatic volatile inputs.
The chemical and D, O, S, and Sr isotopic composition of 26 thermal waters (>25 °C) and 25 cold waters from springs and wells in Okayama Prefecture were investigated to examine the geochemical characteristics of the geothermal resources in a non-volcanic region. No clear geochemical difference was noted between the thermal and cold waters. Some of these waters were formed by mixing of fossil seawater and meteoric water; however, most with low salt concentrations are of meteoric origin and are presumed to have flowed out with a residence time of several months. The waters studied were classified as Ca²⁺−HCO3⁻ and Na⁺−HCO3⁻ types, with ⁸⁷Sr/⁸⁶Sr values close to those of the granite base. These thermal and cold waters were formed by an infiltration of meteoric water into the granite layer that subsequently reacted with carbonate and clay minerals. Considering the main chemical components of the waters, the estimated maximum underground temperature was approximately 100 °C. Therefore, the utilization of these geothermal resources for geothermal heat pumps was judged to be effective even though calcium carbonate scale could precipitate in the heat exchanger.
Geothermal waters from a 1,100-m-deep geothermal well (No. 7) in the vicinity of Yakedake volcano in Gifu Prefecture, central Japan, were monitored for 1 year for chemical and isotope (D, O, and Sr) composition to examine their source. Drill cuttings from the well and surrounding hot spring waters were also analyzed for ⁸⁷Sr/⁸⁶Sr ratios and chemical composition. Combining the calculated reservoir temperatures for geothermal waters from well No. 7 and the ⁸⁷Sr/⁸⁶Sr ratios obtained, we suggest a shallow source for the geothermal waters, such as the Cretaceous to Paleogene Kasagatake Rhyolites, and propose downward-flowing meteoric waters as dominant at depth where the geothermal waters are enriched in Ca²⁺, K⁺, and Sr²⁺ by the interaction with reservoir rock. The ⁸⁷Sr/⁸⁶Sr ratios of hot spring waters in the Shinhirayu area, west of well No.7, are lower than those in three adjacent areas (Nakao, Gamada, and Hirayu), reflecting differences between the geologic formations comprising the reservoir rocks. The geothermal water from well No. 7 and hot spring waters in the study area are not in chemical equilibrium with the reservoir rocks because the reservoirs are young and not strongly altered.
Rare Earth Elements (REE; lanthanides and yttrium) are elements with high economic interest because they are critical elements for modern technologies. This study mainly focuses on the geochemical behavior of REE in hyperacid sulphate brines in volcanic-hydrothermal systems, where the precipitation of sulphate minerals occurs. Kawah Ijen lake, a hyperacid brine hosted in the Ijen caldera (Indonesia), was used as natural laboratory. ∑REE concentration in the lake water is high, ranging from 5.86 to 6.52 mg kg⁻¹. The REE pattern of lake waters normalized to the average local volcanic rock is flat, suggesting isochemical dissolution. Minerals spontaneously precipitated in laboratory at 25 °C from water samples of Kawah Ijen were identified by XRD as gypsum. Microprobe analyses and the chemical composition of major constituents allow to identify possible other minerals precipitated: jarosite, Al-sulphate and Sr, Ba-sulphate. ∑REE concentration in minerals precipitated (mainly gypsum) range from 59.53 to 78.64 mg kg⁻¹. The REE patterns of minerals precipitated normalized to the average local magmatic rock show enrichment in LREE. The REE distribution coefficient (KD), obtained from a ratio of its concentration in the minerals precipitated (mainly gypsum) and the lake water, shows higher values for LREE than HREE. KD-LREE/KD-HREE increases in the studied samples when the concentrations of BaO, MgO, Fe2O3, Al2O3, Na2O and the sum of total oxides (except SO3 and CaO) decrease in the solid phase. The presence of secondary minerals different than gypsum can be the cause of the distribution coefficient variations.
High concentrations of REE in Kawah Ijen volcanic lake have to enhance the interest on these environments as possible REE reservoir, stimulating future investigations. The comparison of the KD calculated for REE after mineral precipitation (mainly gypsum) from Kawah Ijen and Poás hyperacid volcanic lakes allow to generalize that the gypsum precipitation removes the LREE from water.
Geothermal fluids and volcanic emissions are important sources of arsenic (As), resulting in elevated concentrations of As in ground-, surface-water and soil, which may adversely affect the environment. Arsenic originating from geothermal features and volcanic activities is common in Latin America forming a serious threat to the livelihoods of millions of people. This review attempts to provide a critical overview of the geochemistry of As originating from these sources in Latin America to understand what information exists about and what future research needs to be undertaken. This study evaluated 15 countries in Latin America. In total, 423 sites were characterized with As originating from geothermal sources, mostly related to present volcanic activity (0.001 < As<73 mg/L, mean: 36.5 mg/L) and the transboundary Guarani Aquifer System (0.001 < As<0.114 mg/L, mean: 0.06 mg/L). Many of the geothermal systems and volcanoes discussed in this study are close to densely populated cities, including Bogota, Managua, San José, Guatemala City and Mexico City, where total As concentrations in natural ground- and surface- water exceed the safe drinking water guideline of 0.01 mg/L, recommended by the World Health Organization (WHO). However, the wide geographical occurrence of As in geothermal fluids and volcanic emissions of this region is by far not fully understood, so that development of geographical maps based on geographic information system (GIS) is an urgent necessity to understand the real nature of the problem. The assessment of environmental risks and the potential impacts on human health both inadequate and scarce and hence, these gaps need to be addressed by future research. The present holistic assessment of As originating from geothermal features and volcanic emissions would be a driving force to formulate a plan for establishing a sustainable As mitigation in vulnerable areas of Latin America in the near future. An assessment of the geochemistry, mobility and distribution of As would augment the effectiveness of the plan.
El Chichón crater lake is characterized by important variations in volume (40,000 m³ to 230,000 m³) and in chemical composition alternating between acid-sulfate and acid-chloride-sulfate composition (Cl-/SO4(2-) = 0-79 molar ratio). These variations in volume can occur very fast within less than a few weeks, and are not always directly correlated with the precipitation rate; the seepage rate of lake water is also an important parameter to consider in the lake mass balance. In this study, we present for the first time continuous physical data (temperature, depth, precipitation, wind velocity, solar radiation) of the crater lake registered by a meteorological station and two dataloggers. A heat and mass balance approach is proposed to estimate the heat and mass fluxes injected into the lake by the sublacustrine fumaroles and springs. Tracing the evolution of such fluxes can be helpful to understand this highly dynamic lake and offers an efficient way of monitoring the volcanic activity. During the observation period, the hydrothermal heat flux was estimated to be 17-22 MW, and the mass flux 10-12 kg/s (error on both values of ± 15%). These fluxes are mainly counterbalanced by the loss of heat and mass by evaporation, respectively of 20-24 MW and 8-10 kg/s. Furthermore, the seepage rate of the lake waters was estimated and shown to be a highly variable parameter (12-42 kg/s), depending on the lake surface. This new data set constitutes a baseline to monitor the future activity of El Chichón volcano. In case of volcanic activity renewal, one of the first precursor signals would probably be the full evaporation of the lake.
This study focuses on the characterisation and origin of hydrothermal waters discharging from three main active volcanoes (Furnas, Fogo and Sete Cidades) at São Miguel, where 33 water with temperatures ranging between 13 and 97 °C, and 5 precipitate samples were collected. The developed conceptual model for this active hydrothermal system reveals that all waters can be classified by Na-HCO3, Na-Cl and Na-SO4 types and are of meteoric origin. This is confirmed by the stable hydrogen and oxygen isotope data that are positioned close to the local meteoric water line (− 4.1‰ ≤ δ¹⁸OH2O ≤ 5.2‰; − 17.6‰ ≤ δDH2O ≤ 20.4‰), except for the Na-Cl type water at Ferraria (Sete Cidades area), which is characterized by admixing of seawater. The stable isotope composition of São Miguel hydrothermal solutions (δ³⁴SSO4 range from 21.3 to − 3.7; δ¹⁸OSO4 range between 0.5 and 10.5‰; δ¹³CTDIC = − 4.5 ± 3.2‰) indicate that waters are individually evolved by several processes: evaporation, uptake of volcanogenic sulphur and carbon dioxide, leaching of local volcanic rocks (driven by high CO2 contents and/or elevated temperature), and biological activity. Latter hydrochemical superimposition is displayed by stromatolitic structures in the precipitates at the given site. Dissolved REE data show similar pattern as local volcanic rocks. In particular the distinct Eu anomaly hints to preferential leaching of locally occurring trachyte. The strongly acidic Na-SO4 waters sampled in boiling pools at Fogo and Furnas Lake indicate high leaching levels and LREE depletion versus HREE compared with the volcanic local rock compositions. Depletion in LREE is most likely caused by its preferential removal compared to HREE by the co-precipitation with alunite.
Late Quaternary volcanism in central Mexico is related to the subduction of young ocean lithosphere at the Middle America Trench. Along-arc variations in seismicity, volcano structure, and composition of volcanic products bear a remarkable correlation with the age and structural framework of the downgoing slab. Morphological and petrographic characteristics of major volcanoes within the Trans-Mexican Volcanic Belt (TMVB) serve to distinguish two calc-alkaline subprovinces: 1) A W arc, averaging 60km in width, associated with aseismic subduction of the Rivera plate. The main cones of this region are dominated by two-pryoxene andesites, comprise volumes = or <70km3, and stand <3000m above sea level. 2) A broad central and E arc related to subduction of the gently inclined segment of the Cocos plate bounded by the Rivera transform and the Tehuantepec Ridge. Major volcanic edifices possess summit elevations in the range 4000-6000m, have appropriately larger volumes (typically >200km3) and are constructed with a high proportion of amphibole-bearing lavas. A third segment of ocean floor is presently interacting with continental lithosphere S of the Gulf of Tehuantepec, where Quaternary volcanism is weakly developed within a tectonically complex region that marks the diffuse Cocos-NOAM-Caribbean triple junction. A tectonic reconstruction based on the evolution of oceanic crust reveals that the distribution of intermediate-depth earthquakes along the arc is directly dependent upon the age of the subducted slab. Ocean lithosphere younger than approximately 20Ma. is subducted aseismically at convergence rates approaching 9 cm/yr. The length of the inclined seismic zone indicates that the time constant for thermal relaxation in the slab is approximately 4Ma. The TMVB overlies the aseismic extension of ths young ocean lithosphere.-Author
Chemical and strontium isotopic analyses have been performed on 10 geothermal waters from the Valles caldera/Jemez Mountain region, as well as 10 rock samples collected in the VC-1 scientific core hole. The 87Sr/86Sr values of other rocks sampled in the Jemez Mountains have also been used in this study to understand relations between the fluids and rocks of the volcanically driven geothermal system and the lateral outflow plume, discharging down the Jemez fault zone. The strontium content of ground-water is linked to the host rock composition, the aquifer temperature, and therefore the solubility of Sr-containing minerals. Low Sr concentrations in the fluid are found with a high temperature and/or volcanic host rocks, whereas high Sr concentrations are characteristic of a low temperature and/or a Paloezoic sedimentary aquifer. Important variations of the 87Sr/86Sr value in hydrothermal waters (0.70842-0.72193) are related to chemical composition, Sr content, and host rocks. For VC-1 core samples, the Sr isotopic ratios are also markedly variable (0.70459-0.75686), low for the Quaternary volcanics and high for the Paleozoic sedimentary rocks. The same observation is made for other Jemez Mountains rocks (0.70465-0.8163) with, in addition, high 87Sr/86Sr values for Precambrian crystalline rocks. A good correspondence is generally found between the waters and the reservoir rocks studied here, which indicates that isotopic equilibrium is rapidly attained. The following suite of hydraulically related fluids displays a progressive enrichment in radiogenic strontium: Baca wells (87Sr-86Sr=0.7084-0.7094), VC-1 core hole at 483 m (0.7152-0.7154), Main Jemez Spring (0.7217), and Soda Dam (0.7219). This trend is associated with flow through Paleozoic rocks and with the length of the flow path from the center of Valles caldera (primary geothermal fluids) toward San Deigo Canyon, along the Jemez fault zone (derivative waters).
The origin and evolution of formation water from Upper Jurassic to Upper Cretaceous mudstone–packstone–dolomite host rocks at the Jujo–Tecominoacán oil reservoir, located onshore in SE-Mexico at a depth from 5200 to 6200 m.b.s.l., have been investigated, using detailed water geochemistry from 12 producer wells and six closed wells, and related host rock mineralogy. Saline waters of Cl–Na type with total dissolved solids from 10 to 23 g/L are chemically distinct from hypersaline Cl–Ca–Na and Cl–Na–Ca type waters with TDS between 181 and 385 g/L. Bromine/Cl and Br/Na ratios suggest the subaerial evaporation of seawater beyond halite precipitation to explain the extreme hypersaline components, while less saline samples were formed by mixing of high salinity end members with surface-derived, low salinity water components. The dissolution of evaporites from adjacent salt domes has little impact on present formation water composition. Geochemical simulations with Harvie-Mφller-Weare and PHRQPITZ thermodynamic data sets suggest secondary fluid enrichment in Ca, HCO3 and Sr by water–rock interaction. The volumetric mass balance between Ca enrichment and Mg depletion confirms dolomitization as the major alteration process. Potassium/Cl ratios below evaporation trajectory are attributed to minor precipitation of K feldspar and illitization without evidence for albitization at the Jujo–Tecominoacán reservoir. The abundance of secondary dolomite, illite and pyrite in drilling cores from reservoir host rock reconfirms the observed water–rock exchange processes. Sulfate concentrations are controlled by anhydrite solubility as indicated by positive SI-values, although anhydrite deposition is limited throughout the lithological reservoir column. The chemical variety of produced water at the Jujo–Tecominoacán oil field is related to a sequence of primary and secondary processes, including infiltration of evaporated seawater and original meteoric fluids, the subsequent mixing of different water types and the formation of secondary minerals by water–rock interaction. A best fit between measured and calculated reservoir temperatures was obtained with the Mg–Li geothermometer for high salinity formation water (TDS > 180 g/L), whereas Na–K, Na–Ka–Ca and quartz geothermometers are partially applicable for less salinite water (TDS < 23 g/L).
The 1982 eruption of El Chichón volcano ejected more than 1 km3 of anhydrite-bearing trachyandesite pyroclastic material to form a new 1-km-wide and 300-m-deep crater and uncovered the
upper 500 m of an active volcano-hydrothermal system. Instead of the weak boiling-point temperature fumaroles of the former
lava dome, a vigorously boiling crater spring now discharges / 20 kg/s of Cl-rich (∼15 000 mg/kg) and sulphur-poor ( / 200 mg/kg
of SO4), almost neutral (pH up to 6.7) water with an isotopic composition close to that of subduction-type magmatic water (δD=–15‰,
δ18O=+6.5‰). This spring, as well as numerous Cl-free boiling springs discharging a mixture of meteoric water with fumarolic
condensates, feed the crater lake, which, compared with values in 1983, is now much more diluted (∼3000 mg/kg of Cl vs 24 030 mg/kg),
less acidic (pH=2.6 vs 0.56) and contains much lower amounts of S ( / 200 mg/kg of SO4, vs 3550 mg/kg) with δ34S=0.5–4.2‰ (+17‰ in 1983). Agua Caliente thermal waters, on the southeast slope of the volcano, have an outflow rate of approximately
100 kg/s of 71 °C Na–Ca–Cl water and are five times more concentrated than before the eruption (B. R. Molina, unpublished
data). Relative N2, Ar and He gas concentrations suggest extensional tectonics for the El Chichón volcanic centre. The 3He/4He and 4He/20Ne ratios in gases from the crater fumaroles (7.3Ra, 2560) and Agua Caliente hot springs (5.3Ra, 44) indicate a strong magmatic contribution. However, relative concentrations of reactive species are typical of equilibrium
in a two-phase boiling aquifer. Sulphur and C isotopic data indicate highly reducing conditions within the system, probably
associated with the presence of buried vegetation resulting from the 1982 eruption. All Cl-rich waters at El Chichón have
a common source. This water has the appearence of a "partially matured" magmatic fluid: condensed magmatic vapour neutralized
by interaction with fresh volcaniclastic deposits and depleted in S due to anhydrite precipitation. Shallow ground waters
emerging around the volcano from the thick cover of fresh pumice deposits (Red waters) are Ca–SO4–rich and have a negative oxygen isotopic shift, probably due to ongoing formation of clay at low temperatures.
Fluid and heat discharge rates of thermal springs of El Chichón volcano were measured using the chloride inventory method. Four of the five known groups of hot springs discharge near-neutral Na–Ca–Cl–SO4 waters with a similar composition (Cl ∼ 1500–2000 mg kg−1 and Cl/SO4 ∼ 3) and temperatures in the 50–74 °C range. The other group discharges acidic (pH 2.2–2.7) Na–Cl water of high salinity (>15 g/L). All five groups are located on the volcano slopes, 2–3 km in a straight line from the bottom of the volcano crater. They are in the upper parts of canyons where thermal waters mix with surface meteoric waters and form thermal streams. All these streams flow into the Río Magdalena, which is the only drainage of all thermal waters coming from the volcano. The total Cl and SO4 discharges measured in the Río Magdalena downstream from its junction with all the thermal streams are very close to the sum of the transported Cl and SO4 by each of these streams, indicating that the infiltration through the river bed is low. The net discharge rate of hydrothermal Cl measured for all thermal springs is about 468 g s−1, which corresponds to 234 kg s−1 of hot water with Cl = 2000 mg kg−1. Together with earlier calculations of the hydrothermal steam output from the volcano crater, the total natural heat output from El Chichón is estimated to be about 160 MWt. Such a high and concentrated discharge of thermal waters from a hydrothermal system is not common and may indicate the high geothermal potential of the system. For the deep water temperatures in the 200–250 °C range (based on geothermometry), and a mass flow rate of 234 kg s−1, the total heat being discharged by the upflowing hot waters may be 175–210 MWt.
Combined B, O, H, and Sr isotopic studies of groundwaters from Mt. Etna provide new constraints on their origin and the consequences of fluid-rock interaction within this hydrologic system. Variations in δ18O (−9.7 to −7.2‰) and δD (−62 to −23‰) mainly lie along the regional meteoric water line and suggest that most waters originated as local precipitation. However, small shifts in δ18O, and variable 87Sr/86Sr (0.70355 to 0.70879) and δ11B (−5.2 to +25.8‰) indicate that subsequent interactions occurred between the fluids and local rocks. High B/Cl ratios in all samples seemingly preclude direct involvement of seawater in the hydrologic system despite the proximity to the coast and, in some samples, elevated 87Sr/86Sr and δ11B. Two general ‘end-member’ water types are recognized on the basis of their chemistry. These apparently are produced by interactions of local meteoric waters with the dominant reservoir rocks—either basaltic lavas of Etna or the underlying sediments, respectively; high δ11B in the sediment-hosted end-member points to a significant marine carbonate contribution. Subsequent mixing between these or similar end-members produced a range of intermediate composition groundwaters. Certain anomalous water compositions require the presence locally of a distinct component with high B and moderate δ11B (ca. +10‰) but relatively low 87Sr/86Sr; an anthropogenic source for this component is plausible. One unusual sample has B and Sr isotopic compositions similar to the other volcanic rock-hosted waters, but anomalously high Cl content that likely reflects local magmatic outgassing near this sampling locality. In general, this study indicates that groundwater B and Sr isotopic compositions are rock-dominated; these data provide useful constraints on the origin and evolution of groundwaters.
Thirty-five ground-water samples have been collected from wells, springs and drainage galleries on Mt Etna volcano for the determination of major, minor and trace elements in solution. Attention has been focused in particular on dissolved minor and trace elements, for most of which no data were available in the studied area. In general, dissolution of solids into Etna's ground waters follows from strong interaction between water of meteoric origin, CO2 gas of magmatic origin and the volcanic rocks of the aquifers. However, the R-mode analysis allowed to distinguish several sources of solutes: Al, Co, Ni, Fe, Si, As would derive mainly from alteration of the volcanic rocks of Etna; SO4=, K, Na, V, Sr, Mo, Cr and calculated p(CO2) would instead indicate a major contribution of volcanic gases (mostly CO2 and SO2); and TDS, HCO3=, Li Mg, B and Cl− would indicate a derivation from both these sources. Se, Hg, Cu and Mn would derive from hydrothermal fluids, and Ca would derive both from this latter contribution and from rock alteration. The comparison between trace elements abundance in Etna's ground waters and that in the ground waters of other areas of Italy showed that, in general, Etna's waters, like other volcanic ground waters, are enriched in Li, Mn, Si, V, As and Mo. Furthermore, in the areas of Mt Etna where the contribution of volcanic gas to the aquifers is greatest, ground waters are also enriched in B, Se, Co, Hg, Al, Fe and Ni. The obtained results show clearly that, in active volcanic areas, many dissolved elements can attain levels that can be appreciably different from those indicated by WHO for drinking water. Therefore, the local geological factors which can influence the geochemical behavior of these elements in solution should be taken into account when establishing national standards for drinking-water quality. In consideration of the local natural background values, concentrations of dissolved elements that differ from the guideline values should be accepted in areas with peculiar geological characteristics, provided that the elements under consideration do not have a direct influence on health. © 1998 Elsevier Science Ltd. All rights reserved
El Chichon volcano is located in the northern part of the State of Chiapas in southeastern Mexico. The volcano is situated within the Transcurrent Fault Province characterized by a series of rising and sinking blocks bounded by sinistral strike-slip faults. The basement around El Chichon is a sequence of Jurassic evaporates, Cretaceous limestones, and Tertiary terrigenous rocks folded into open and an echelon structures. The main structures in the area are the La Union and Caimba anticlines, and the Buena Vista syncline. The region is cross-cut by two conjugate fault systems: a dextral strike-slip N-S-trending set, and a sinistral strike-slip E-W set. The most significant fault of the latter system is the San Juan Fault, which controlled the emplacement of a basaltic dike near the village of Chapultenargo some 1.1 Ma ago and the activity of El Chichon during the last 0.2 Ma. Additionally, a series of N45degreesE-trending faults (Chapultengo Fault System) have produced a half-graben geometry of blocks, on top of which El Chichon has been emplaced. Microstructures such as slickensides, tension fractures, layer-parallel slip, stylolites, and macro- and meso-folds of the sedimentary rocks, indicate that, during the late Miocene the El Chichon area was affected by a maximum principal stress (sigma(1)) oriented N70degreesE, a minimum principal stress (sigma(3)) oriented N20degreesW, and a vertical intermediate principal stress. This stress pattern indicates that the area underwent a strike-slip motion that produced widespread deformation. The occurrence of crustal earthquakes (<40 km) in the region with sinistral strike-slip focal mechanisms oriented along the major faults suggests that the same tectonic regime has been occurring in southern Mexico from the late Miocene to the Recent, controlling the emplacement and activity of El Chichon since its beginning during the Pliocene to Recent. This tectonic setting has produced K-alkaline trachyandesites (55-59% wt. SiO(2)) and K-rich trachybasalts (46 -49% wt. SiO(2)) in the area represented by the 1.1 Ma fissural Chapultenango basalt, and by mafic enclaves. Despite this alkaline nature, El Chichon magmas display enrichments in K(2)O, Rb, and Sr typical of continental arc magmatism.
The Mammoth Corridor in and adjacent to Yellowstone National Park encompasses a N-S alignment of geothermal features that extends from the Norris Geyser Basin adjacent to the Yellowstone caldera through Mammoth Hot Springs to the Corwin Springs Known Geothermal Resources Area (KGRA). Thermal springs in this region discharge water that ranges from Na-K-Cl, silica-depositing type to Ca-Na-HCO3-SO4, travertine-depositing type. Although only a few relatively shallow wells have been drilled in the corridor, the region is of special interest because of the environmental issues associated with potential geothermal development adjacent to Yellowstone National Park. The U.S. Geological Survey conducted an intensive hydrogeologic study of this region during 1988-1990 and continued to collect hydrologic and geophysical data until 1994. The results of these investigations document the rates of discharge of thermal water and heat within the corridor, evidence for a magmatic heat source beneath the Mammoth Hot Springs area, and evidence for separate geothermal systems associated with Mammoth Hot Springs and with thermal waters discharging in the KGRA in the vicinity of La Duke Hot Springs. These investigations also indicate that limited development of the 70°C geothermal resource in the La Duke area would not affect thermal springs in Yellowstone National Park. © 1997 CNR. Published by Elsevier Science Ltd. All rights reserved.
Speciation and mineral saturation modeling, bulk sediment analyses, and micro-probe sediment analyses indicate that the lakes are reducing at depth, and all three lakes are close to saturation with gypsum/anhydrite. One lake is also saturated with Fe-oxides, while the other two are thought to be saturated with a suite of Cu and As minerals. The most acid lake is also saturated with native sulfur and possibly pyrite. Mass balance estimates based on fresh volcanic rocks and ashes, the dissolved element load and the lake sediment chemistry strongly suggest that the lakes are partly fed by underlying geothermal circulation systems. The lakes are thus not closed reaction vessels with dissolution of local rock debris by fluids acidified by volcanic gases, but they draw a rock-derived element flux from deeper levels. Mass transfer is large in these dynamic systems, including the transport of tonnes of ore metals over a period of centuries. -from Authors
Four groups of thermal springs with temperatures from 50 to 80 °C are located on the S–SW–W slopes of El Chichón volcano, a composite dome-tephra edifice, which exploded in 1982 with a 1 km wide, 160 m deep crater left. Very dynamic thermal activity inside the crater (variations in chemistry and migration of pools and fumaroles, drastic changes in the crater lake volume and chemistry) contrasts with the stable behavior of the flank hot springs during the time of observations (1974–2005). All known groups of hot springs are located on the contact of the basement and volcanic edifice, and only on the W–SW–S slopes of the volcano at almost same elevations 600–650 m asl and less than 3 km of direct distance from the crater. Three groups of near-neutral (pH ≈ 6) springs at SW–S slopes have the total thermal water outflow rate higher than 300 l/s and are similar in composition. The fourth and farthest group on the western slope discharges acidic (pH ≈ 2) saline (10 g/kg of Cl) water with a much lower outflow rate (< 10 l/s).
This paper reports that strontium isotope compositions of Rotorua geothermal waters, taken in conjunction with chemical and stable isotope data, are broadly consistent with existing hydrogeologic models, and provide new insights into complex water-rock interactions and fluid-fluid mixing processes. Primary alkali chloride water upwelling in the eastern part of the field have â¸â·Sr/â¸â¶Sr ratios higher than their presumed aquifer wall rocks, implying a component of more radiogenic strontium from metasedimentary basement. Secondary waters, in contrast, have relatively low â¸â·Sr/â¸â¶Sr ratios consistent with interaction of primary fluids (variably diluted by deep groundwaters) with rhyolite country rock, followed by shallow dilution by young groundwater. Although complicated by the non-conservative behavior of strontium, the strontium isotope data require significant water-rock interaction in the central and western parts of the Rotorua geothermal field, a feature not made obvious by other chemical or isotope studies.
Relative Na, K, Mg, and Ca contents of thermal waters in full equilibrium with a thermodynamically stable mineral system derived through isochemical recrystallization of an average crustal rock are, at a given temperature and salinity, uniquely fixed. Together with the compositions of waters resulting from isochemical rock dissolution, they provide valuable references for the assessment of the degree of attainment of fluid-rock equilibrium. The subsystems are combined to obtain graphical techniques for the evaluation of deep temperatures and COâ-partial pressures by use of Na, K, Mg and Ca contents of geothermal water discharges.
Well BrO-29 at the Broadlands-Ohaaki geothermal system, New Zealand, penetrates a mixed volcanic/sedimentary rock sequence whose 87Sr/86Sr ratios display linear distributions when plotted against 1/Sr values. These linear distributions do not indicate binary mixing between unaltered lithological units and a single fluid endmember. The linear distribution in the volcanic/pyroclastic sequences is related to the permeability of the host rocks, the degree of leaching of 86Sr rich primary plagioclase laths, and secondary crystallisation of the groundmass by a recharge fluid represented by modified Taupo rainwater. The greywacke/argillite basement from the same well displays a separate linear isotopic trend when their 87Sr/86Sr ratios are plotted against 1/Sr values, in addition to yielding a Sr/ Sr vs. Rb/Sr errorchron with an age of 88± 6 Ma BP (MSWD = 9.48). Based upon supporting petrographic observations, the two isotopic trends in the greywacke/argillite basement are believed to be an inherited metamorphic feature, from the Rangitata Orogeny (141±3 Ma), which has been modified by geothermal fluids preferentially leaching 87Sr and 87Rb from primary micas.
Aquifer fluid compositions and aqueous species distribution have been calculated for 22 samples collected from producing wells in the Krafla and Námafjall geothermal areas, Iceland. Overall mineral–solution equilibrium is rather closely approached in the aquifer beyond the depressurization zone around wells for all major components entering hydrothermal minerals. The minerals involved are in alphabetical order: albite, calcite, chlorite, epidote, K-feldspar (adularia), prehnite, pyrite, pyrrhotite, quartz and wairakite. Calculated saturation indices for OH-bearing Al–silicates show more scatter than for minerals of simpler composition. A large scatter is also observed for pyrite and pyrrhotite. The main uncertainty involved in calculating mineral saturation indices, particularly in the case of “excess” enthalpy well discharges, lies in the model adopted to calculate the aquifer water composition and its aqueous species distribution and not in the quality of the thermodynamic data on the aqueous species and the minerals with the possible exception of epidote and Fe2+.
Compositional and isotopic zoning patterns in plagioclase and amphibole phenocrysts from El Chichón record multiple cycles of country rock assimilation, magma injection, hybridization, and mixing. Laser ablation ICP-MS and electron microprobe analyses of plagioclase crystals from 7 eruptions spanning 3100 years reveal four types of zoning. These compositional and isotopic zones are often associated with textural changes observed in the crystals in thin section (e.g. sieved or patchy regions). Amphiboles are frequently zoned in Al and Si, and, in two magmas, may have clinopyroxene rims. Interestingly, most plagioclase show multiple and repeated zoning patterns. Moreover, all magmas contain all zoning patterns and textures, and crystals with substantially different sequences of zones occur within mm of one another. The most reasonable explanation for the origin of these textures is a frequently recharged chamber. Plagioclase zones with increasing anorthite contents (An) and decreasing 87Sr/86Sr ratios record injection by a hotter, possibly wetter, and more primitive magma (lower 87Sr/86Sr ratio). Zones with decreasing An and increasing 87Sr/86Sr ratios record assimilation of country rock and/or hybridization of the host and injected magmas; injection of hot magma may provide the heat for country rock assimilation. Changes in An without corresponding changes in 87Sr/86Sr ratio likely record slight variations in pressure or temperature during crystallization, or the far-field thermal effects of magma injection. Variations in 87Sr/86Sr ratio unaccompanied by Anzoning record assimilation of country rock. Amphibole zoning patterns also record periodic heating events; amphibole with clinopyroxene rims record episodes where the magma was heated beyond the amphibole stability field. Bulk compositional homogeneity and the juxtaposition of many crystals with disparate zoning patterns in single pumice require the magmatic system to be well mixed. Strontium diffusion rates indicate that the plagioclase zoning patterns cannot have persisted at magmatic pressures and temperatures for more than ~500 years, thus cycles of injection and assimilation occur on timescales equal to or shorter than the eruption recurrence interval. Long-term compositional and isotopic homogeneity indicate that there is a balance between recharge, assimilation, and crystallization.
Meteoric waters from cold springs and streams outside of the 1912 eruptive deposits filling the Valley of Ten Thousand Smokes (VTTS) and in the upper parts of the two major rivers draining the 1912 deposits have similar chemical trends. Thermal springs issue in the mid-valley area along a 300-m lateral section of ash-flow tuff, and range in temperature from 21 to 29.8°C in early summer and from 15 to 17°C in mid-summer. Concentrations of major and minor chemical constituents in the thermal waters are nearly identical regardless of temperature. Waters in the downvalley parts of the rivers draining the 1912 deposits are mainly mixtures of cold meteoric waters and thermal waters of which the mid-valley thermal spring waters are representative. The weathering reactions of cold waters with the 1912 deposits appear to have stabilized and add only subordinate amounts of chemical constituents to the rivers relative to those contributed by the thermal waters. Isotopic data indicate that the mid-valley thermal spring waters are meteoric, but data is inconclusive regarding the heat source. The thermal waters could be either from a shallow part of a hydrothermal system beneath the 1912 vent region or from an incompletely cooled, welded tuff lens deep in the 1912 ash-flow sheet of the upper River Lethe area.Bicarbonate-sulfate waters resulting from interaction of near-surface waters and the cooling 1953–1968 southwest Trident plug issue from thermal springs south of Katmai Pass and near Mageik Creek, although the Mageik Creek spring waters are from a well-established, more deeply circulating hydrothermal system. Katmai caldera lake waters are a result of acid gases from vigorous drowned fumaroles dissolving in lake waters composed of snowmelt and precipitation.
The volcanic Ascension Island is located about 100 km west of the median valley of the Mid-Atlantic Ridge. A 3126 m-deep well was drilled on the island to investigate the geothermal system associated with the recent volcanism. Two types of fluid were encountered in the well, both derived from seawater. The first fluid, found at 2500 m depth, was a recent mixture of a gaseous phase rich in volcanic CO2 and a geothermal fluid. Flow from this entry was so rich in gas that a CO2H2O froth was formed in the wellbore. The second fluid was water produced by a gas lift from near the bottom of the well at 2957 m. The water appeared to have normal gas concentrations. The geothermometer temperatures of water from the shallow and deep fluid entries were 200 and 245°C, respectively. The geothermometer and the measured temperatures were in close agreement, suggesting low permeability in the geothermal system.
El Chichón volcano has produced at least 11 eruptive events in the past 8000 years, all of which display a relatively constant trachyandesitic composition. The constancy of the eruptive products attests to the tapping of a long-lived magma chamber and suggests a system held in steady state between the influx of basaltic magma and differentiation of resident magma. We have sampled eruptive products from eight of these events, subjecting their dominant phenocryst phases (plagioclase and hornblende) to argon isotopic analysis in order to investigate the dynamics of a steady state magmatic system. Plagioclase from the older eruptions, 1500 yr BP, 1600 yr BP, 2000 yr BP and 3100 yr BP, display variable enrichment of 40Ar (excess argon), whereas hornblende from the same eruptions shows little or no enrichment. In contrast, both plagioclase and hornblende phenocrysts from the younger eruptions in 1982, 550 yr BP, 900 yr BP and 1250 yr BP have argon isotopic ratios near-atmospheric values. Isochron analysis of these mineral phases rules out xenocrystic contamination as the source of excess argon, while mafic enclaves and isotopic and compositional zoning evidence frequent recharge events, suggesting the source of this argon is most likely the same as the source of this basaltic magma; correlation with Cl points to melt/vapor inclusions as the primary host for Ar within the phenocrysts. Argon isotopic variations point to a disturbance of the system between 1500 yr BP and 1250 yr BP, while compositional evidence for a major mafic input is present in the 900 yr BP eruption, indicating a complex relationship between recharge and isotopic signature of eruptive products. The amount of excess argon within a plagioclase phenocryst are a function of variations in melt and vapor inclusion abundance, time elapsed between melt/vapor inclusion entrapment and eruption, variations in Ar abundance in melt (itself a function of vapor exsolution timing) and time variations in Ar isotopic composition of the melt; subdued behavior of hornblende is due to slower diffusion and minimal inclusions.
The 87Sr/86Sr values of thermal waters and hydrothermal calcites of the Long Valley caldera geothermal system are more radiogenic than those of young intracaldera volcanic rocks. Five thermal waters display 87Sr/86Sr of 0.7081-0.7078 but show systematically lighter values from west to east in the direction of lateral flow. We believe the decrease in ratio from west to east signifies increased interaction of deeply circulating thermal water with relatively fresh volcanic rocks filling the caldera depression. All types of pre-, syn-, and post-caldera volcanic rocks in the west and central caldera have (87Sr/86Sr)m between about 0.7060 and 0.7072 and values for Sierra Nevada granodiorites adjacent to the caldera are similar. Sierran pre-intrusive metavolcanic and metasedimentary rocks can have considerably higher Sr-isotope ratios (0.7061-0.7246 and 0.7090-0.7250, respectively). Hydrothermally altered volcanic rocks inside the caldera have (87Sr/86Sr)m slightly heavier than their fresh volcanic equivalents and hydrothermal calcites (0.7068–0.7105) occupy a midrange of values between the volcanic/plutonic rocks and the Sierran metamorphic rocks. These data indicate that the Long Valley geothermal reservoir is first equilibrated in a basement complex that contains at least some metasedimentary rocks. Reequilibration of Sr-isotope ratios to lower values occurs in thermal waters as convecting geothermal fluids flow through the isotopically lighter volcanic rocks of the caldera fill.
Adsorption is the predominate mechanism controlling transport of arsenic in many ground water systems. Hydrous oxides of iron,
aluminum, and manganese, and clay minerals are commonly associated with aquifer solids and have been shown to be significant
adsorbents of arsenic. The extent of arsenic adsorption is influenced by the chemistry of the aqueous phase including pH,
arsenic speciation, and the presence and concentration of competing ions. Under moderately reducing conditions, trivalent
arsenite is stable and adsorption increases with increasing pH. In an oxidizing environment, arsenate is stable and adsorption
decreases with increasing pH. The presence of phosphate, sulfate, carbonate, silica, and other anions have been shown to decrease
adsorption of arsenic to varying degrees. The effects of complex aqueous and solid phase chemistry on arsenic adsorption are
best simulated using surface complexation models. Coupling of such models with hydrologic solute transport codes provide a
powerful method for predicting the spatial and temporal distribution of arsenic in ground water.
The June 1991 eruption of Mount Pinatubo, Philippines breached a significant, pre-eruptive magmatic-hydrothermal system consisting of a hot (>300C) core at two-phase conditions and surrounding, cooler (<260C) liquid outflows to the N and S. The eruption created a large, closed crater that accumulated hydrothermal upwellings, near-surface aquifer and meteoric inflows. A shallow lake formed by early September 1991, and showed a long-term increase in level of ~1m/month until an artificial drainage was created in September 2001. Comparison of the temporal trends in lake chemistry to pre- and post-eruptive springs distinguishes processes important in lake evolution. The lake was initially near-neutral pH and dominated by meteoric influx and Cl–SO4 and Cl–HCO3 hydrothermal waters, with peaks in SO4 and Ca concentrations resulting from leaching of anhydrite and aerosol-laden tephra. Magmatic discharge, acidity (pH~2) and rock dissolution peaked in late 1992, during and immediately after eruption of a lava dome on the crater floor. Since cessation of dome growth, trends in lake pH (increase from 3 to 5.5), temperature (decline from 40 to 26C), and chemical and isotopic composition indicate that magmatic degassing and rock dissolution have declined significantly relative to the input of meteoric water and immature hydrothermal brine. Higher concentrations of Cl, Na, K, Li and B, and lower concentrations of Mg, Ca, Fe, SO4 and F up to 1999 highlight the importance of a dilute hydrothermal contribution, as do stable-isotope and tritium compositions of the various fluids. However, samples taken since that time indicate further dilution and steeper trends of increasing pH and declining temperature. Present gas and brine compositions from crater fumaroles and hot springs indicate boiling of an immature Cl–SO4 geothermal fluid of near-neutral pH at approximately 200C, rather than direct discharge from magma. It appears that remnants of the pre-eruptive hydrothermal system invaded the magma conduit shortly after the end of dome emplacement, blocking the direct degassing path. This, along with the large catchment area (~5km2) and the high precipitation rate of the area, led to a rapid transition from a small and hot acid lake to a large lake with near-ambient temperature and pH. This behavior contrasts with that of peak-activity lakes that have more sustained volcanic gas influx (e.g., KawahIjen, Indonesia; Poas and Rincn de la Vieja, Costa Rica).
During 2007–2008, three CO2 flux surveys were performed on El Chichón volcanic lake, Chiapas, Mexico, with an additional survey in April 2008 covering
the entire crater floor (including the lake). The mean CO2 flux calculated by sequential Gaussian simulation from the lake was 1,190 (March 2007), 730 (December 2007) and 1,134gm−2day−1 (April 2008) with total emission rates of 164 ± 9.5 (March 2007), 59 ± 2.5 (December 2007) and 109 ± 6.6tday−1 (April 2008). The mean CO2 flux estimated from the entire crater floor area was 1,102gm−2day−1 for April 2008 with a total emission rate of 144 ± 5.9tday−1. Significant change in CO2 flux was not detected during the period of survey, and the mapping of the CO2 flux highlighted lineaments reflecting the main local and regional tectonic patterns. The 3He/4He ratio (as high as 8.1 R
A) for gases in the El Chichón crater is generally higher than those observed at the neighbouring Transmexican Volcanic Belt
and the Central American Volcanic Arc. The CO2/3He ratios for the high 3He/4He gases tend to have the MORB-like values (1.41 × 109), and the CO2/3He ratios for the lower 3He/4He gases fall within the range for the arc-type gases. The high 3He/4He ratios, the MORB-like CO2/3He ratios for the high 3He/4He gases and high proportion of MORB-CO2 (M = 25 ±15%) at El Chichón indicate a greater depth for the generation of magma when compared to typical arc volcanoes.
KeywordsEl Chichón–CO2 flux–Crater lake–Gas geochemistry–He–C isotopes–Fumarolic and bubbling gases–Tectonics
The Mammoth Corridor in and adjacent to Yellowstone National Park encompasses a N-S alignment of geothermal features that extends from the Norris Geyser Basin adjacent to the Yellowstone caldera through Mammoth Hot Springs to the Corwin Springs Known Geothermal Resources Area (KGRA). Thermal springs in this region discharge water that ranges from NaKCl, silica-depositing type to CaNaHC03SO4, travertine-depositing type. Although only a few relatively shallow wells have been drilled in the corridor, the region is of special interest because of the environmental issues associated with potential geothermal development adjacent to Yellowstone National Park. The U.S. Geological Survey conducted an intensive hydrogeologic study of this region during 1988–1990 and continued to collect hydrologic and geophysical data until 1994. The results of these investigations document the rates of discharge of thermal water and heat within the corridor, evidence for a magmatic heat source beneath the Mammoth Hot Springs area, and evidence for separate geothermal systems associated with Mammoth Hot Springs and with thermal waters discharging in the KGRA in the vicinity of La Duke Hot Springs. These investigations also indicate that limited development of the 70°C geothermal resource in the La Duke area would not affect thermal springs in Yellowstone National Park.
The 1982 eruptions of El Chichón Volcano produced three major pumice- and ash-fall layers. Fresh pumices from the three layers are indistinguishable porphyritic trachyandesites with 55.9 wt. % SiO2, 2.2% MgO, 2.8% K2O, 0.4% P2O5, and over 1.2% SO3. The pumices contain 58 wt. % crystals dominated by plagioclase (mode An43) and hornblende, with lesser amounts of augite, titanomagnetite, anhydrite, apatite, sphene, pyrrhotite, and biotite enclosed in a vesiculated matrix glass with 68 wt. % SiO2. Anhydrite forms subhedral to euhedral microphenocrysts without reaction coronas, as well as inclusions within the outer zones of major phenocrystic minerals. Inclusions of apatite and glass occur within anhydrite microphenocrysts. Anhydrite was crystallizing from the melt prior to eruption. Pumices resampled some ten months after the eruptions contain only 0.2 wt. % SO3, and have only scattered remnants of anhydrite and traces of gypsum lining vesicles. A single rainy season in Chiapas (>4 m yr⁻¹ rainfall) was sufficient to remove most primary anhydrite, which may be a relatively common igneous mineral, although rarely preserved in the geologic record.
Chemical and isotope compositions of fluid samples, collected between 1974 and 1986 from 52 springs or shallow boreholes located in the Mont-Dore region (Massif Central, France), were examined. Some springs and wells were sampled several times during this period. The fluids emerge from Quaternary volcanic rocks or Paleozoic granite at temperatures between 4 and 62°C, and the origin of the H2O is meteoric. The waters can be classified into three groups: bicarbonate fluids, mixed bicarbonate-chloride fluids (with a mineralization up to 8 g/l), and acid-sulfate fluids. Only two fluids contain sufficient Cl⁻ to be considered as ‘mature’ waters. Previous work has demonstrated that they all contain partly mantle-derived CO2 gas, and that the CO2-rich gas phase and bicarbonate-chloride waters are separated at substantial depth.
Na-Ca-Cl groundwaters with salinities of 1 to 30% discharge from natural springs and artesian wells in Mississippian carbonates and Ordovician sandstones and carbonates in central Missouri. Carbonate saturation and quartz supersaturation are maintained throughout the salinity range. Major and trace element and isotopic variations in the waters are used to place constraints on models for rock-water interaction and regional hydrology.
The groundwaters have δD values that range from −108 to −45‰ and δ^(18)O values that range from −14.7 to −6.5‰ (SMOW). These data lie approximately along the meteoric water line, ranging from values similar to local recharge in Missouri, to significantly lower values that are similar to δ^(18)O and δD for meteoric recharge in high altitude and high latitude regions of North America. The more saline samples have the lowest ^(18)O and D contents, a trend that is opposite to that observed in most other studies of saline waters. The H-O isotopic correlation and the range in salinity and several major and trace element concentrations in central Missouri groundwaters are readily explained by a saline-dilute water mixing model. 87Sr/86Sr ratios for the groundwaters range from 0.7155 to 0.7161. These values are significantly higher than previously published values for: 1) estimates of ^(87)Sr/^(86)Sr in Phanerozoic seawater (0.7068–0.7092); and 2) carbonates of the Mississippian Burlington-Keokuk Fm. (0.7075–0.7105), through which some of the waters migrate as they pass to the surface. ϵNd(0) values in the groundwaters range from −10.9 to −8.1, and ^(147)Sm/^(144)Nd ratios range from 0.108 to 0.128. These values are similar to or lower than previously published analyses of carbonates and other authigenic phases from the Burlington-Keokuk Fm. (mean ϵNd(0) = −7.8 ± 0.8 (1σ); mean ^(147)Sm/^(144)Nd = 0.141).
The H, O, Sr and Nd isotopic data and the results of model calculations preclude: 1) models involving the modification of ancient seawater for the origin of the saline waters, and 2) extensive interaction between the groundwaters and their host carbonates. The waters apparently acquired their δ^(18)O and δD values as meteoric recharge and their 87Sr/86Sr and rare earth element signatures from extraformational crustal sources (high ^(87)Sr/^(86)Sr; low ϵNd(0); low 147Sm/144Nd) and largely preserved these isotopic signatures during subsequent migration through the carbonates. Chemical exchange via rock-water interaction is required for isotopic exchange to occur. Therefore, the present state of chemical equilibrium between the groundwaters and carbonate aquifer minerals may serve to limit rock-water interaction, and hence preserve the extraformational isotopic signatures in the waters.
The integration of geochemical, isotopic and hydrologic data on a local and regional scale suggests a history for the central Missouri groundwaters involving: 1) meteoric recharge in the Front Range of Colorado; 2) dissolution of Permian halite in the subsurface of Kansas; 3) interaction with predominantly silicate mineral assemblages in Paleozoic strata (and possibly Precambrian basement), with aquisition of crustal Sr and REE signatures; 4) dilution and migration to shallow aquifer levels in central Missouri; and 5) mixing with local meteoric recharge through Mississippian carbonates with no significant change of the isotopic signatures acquired in stage (3).
Oil-field waters produced from Mississippian carbonate reservoir rocks in Bindley field, Kansas had an average salinity of about 42.8 mg/l. They were enriched in Ca, Sr, Na, K, Rb, and Li and depleted in Mg relative to sea water at the same level of either Cl or Br concentration. The average abundances of different elements are as follows: Na—13,460 mg/l, K—325 mg/1, Rb—0.9 mg/l, Li—12 mg/l, Ca—1,515 mg/l, Sr—42 mg/l, Mg—430 mg/l, Cl—23,000 mg/l, SO4—2,630 mg/l, Br—32 mg/l. The values of the waters ranged between 0.7221 and 0.7230, whereas the values of the host carbonate rocks were between 0.7090 and 0.7093. The very high values of the waters probably occurred as a result of their reaction with alkali feldspar minerals in buried Precambrian crystalline rocks to the east of the Bindley field. The study demonstrates that despite their residence in carbonate reservoir rocks oil-field waters can retain sufficiently distinct isotopic memory that may provide important dues about mineral-water interactions in the chemical evolutionary history of the waters. The study further indicates that very late diagenetic reactions in many carbonate rocks are of minor extent. Difference in the Sr isotopic data among the oil-field waters suggests that the Sr isotopic data can be used as a reliable guide in recognising existence of separate pools in an oil field.
Rare earth element (REE) concentrations have been determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in acid-sulphate and acid-sulphate-chloride waters and the associated sinters and volcanic rocks from the Yellowstone National Park (YNP), Wyoming, USA, geothermal system. REE concentrations in the volcanic rocks range from 222 to 347 ppm; their chondite-normalised REE patterns are typical of upper continental crust, with LREE > HREE and negative Eu anomalies. Total REE concentrations in the fluids range from 3 to 1133 nmol kg−1 (≥ 162 ppm), and ΣREE concentrations in sinter are ≥ 181 ppm.
El Chichón volcano is located in the northern part of the State of Chiapas in southeastern Mexico. The volcano is situated within the Transcurrent Fault Province characterized by a series of rising and sinking blocks bounded by sinistral strike-slip faults. The basement around El Chichón is a sequence of Jurassic evaporates, Cretaceous limestones, and Tertiary terrigenous rocks folded into open and an echelon structures. The main structures in the area are the La Union and Caimba anticlines, and the Buena Vista syncline. The region is cross-cut by two conjugate fault systems: a dextral strike-slip N–S–trending set, and a sinistral strike-slip E–W set. The most significant fault of the latter system is the San Juan Fault, which controlled the emplacement of a basaltic dike near the village of Chapultenango some 1.1 Ma ago and the activity of El Chichón during the last 0.2 Ma. Additionally, a series of N45°E–trending faults (Chapultengo Fault System) have produced a half-graben geometry of blocks, on top of which El Chichón has been emplaced. Microstructures such as slickensides, tension fractures, layer-parallel slip, stylolites, and macro- and meso-folds of the sedimentary rocks, indicate that, during the late Miocene the El Chichón area was affected by a maximum principal stress (σ1) oriented N70°E, a minimum principal stress (σ3) oriented N20°W, and a vertical intermediate principal stress. This stress pattern indicates that the area underwent a strike-slip motion that produced widespread deformation. The occurrence of crustal earthquakes (<40 km) in the region with sinistral strike-slip focal mechanisms oriented along the major faults suggests that the same tectonic regime has been occurring in southern Mexico from the late Miocene to the Recent, controlling the emplacement and activity of El Chichón since its beginning during the Pliocene to Recent. This tectonic setting has produced K-alkaline trachyandesites (55–59% wt. SiO2), and K-rich trachybasalts (46–49% wt. SiO2) in the area represented by the 1.1 Ma fissural Chapultenango basalt, and by mafic enclaves. Despite this alkaline nature, El Chichón magmas display enrichments in K2O, Rb, and Sr typical of continental arc magmatism.
The (pre-1982) 850-m-high andesitic stratovolcano El Chichón, active during Pleistocene and Holocene time, is located in rugged, densely forested terrain in northcentral Chiapas, México. The nearest neighboring Holocene volcanoes are 275 km and 200 km to the southeast and northwest, respectively. El Chichón is built on Tertiary siltstone and sandstone, underlain by Cretaceous dolomitic limestone; a 4-km-deep bore hole near the east base of the volcano penetrated this limestone and continued 770 m into a sequence of Jurassic or Cretaceous evaporitic anhydrite and halite. The basement rocks are folded into generally northwest-trending anticlines and synclines. El Chichón is built over a small dome-like structure superposed on a syncline, and this structure may reflect cumulative deformation related to growth of a crustal magma reservoir beneath the volcano.
Kawah Putih is a summit crater of Patuha volcano, West Java, Indonesia, which contains a shallow, ∼300 m-wide lake with strongly mineralized acid–sulfate–chloride water. The lake water has a temperature of 26–34°C, pH=<0.5–1.3, and and floating sulfur globules with sulfide inclusions are common. Sulfur oxyanion concentrations are unusually high, with Subaerial fumaroles (<93°C) on the lake shore have low molar SO2/H2S ratios (<2), which is a favorable condition to produce the observed distribution of sulfur oxyanion species. Sulfur isotope data of dissolved sulfate and native sulfur show a significant 34S fractionation (ΔSO4–Se of ⩾20‰), probably the result of SO2 disproportionation in or below the lake. The lake waters show strong enrichments in 18O and D relative to local meteoric waters, a result of the combined effects of mixing between isotopically heavy fluids of deep origin and meteoric water, and evaporation-induced fractionation at the lake surface. The stable-isotope systematics combined with energy-balance considerations support very rapid fluid cycling through the lake system. Lake levels and element concentrations show strong seasonal fluctuations, indicative of a short water residence time in the lake as well.
Strontium isotopes (87Sr/86Sr) are routinely measured in hydrochemical studies to determine sources and mixing relationships. They have proved particularly useful in determining weathering processes and quantifying end-member mixing processes. A number of routine case studies are presented which highlight that Sr isotopes represent a powerful tool in the geochemists toolbox helping to constrain weathering reactions, weathering rates, flow pathways and mixing scenarios. Differences in methodologies for determining the weathering component in natural environments, inherent differences in weathering rates of different minerals, and mineral heterogeneity often cause difficulties in defining the weathering component of different catchments or aquifer systems. Nevertheless, Sr isotopes are useful when combined with other hydrochemical data, to constrain models of water–rock interaction and mixing as well as geochemical processes such as ion-exchange. This paper presents a summary of recent work by the authors in constraining the sources of waters and weathering processes in surface catchments and aquifers, and indicates cases where Sr isotopes alone are insufficient to solve hydrological problems.
Volcanic acid sulfate–chloride brines form through absorption of volcanic vapors in shallow reservoirs of meteoric water. Reaction with surrounding volcanic rocks leads to partial neutralization of the fluids and precipitation of secondary minerals. Chemical data of such acid waters from Copahue volcano, Argentina, covering 8 years of observations, show evidence for changes in composition related to water rock interaction at depth prior to emergence of the fluids at the surface. The chemical composition changed dramatically during the 2000 eruption of Copahue, with enhanced concentrations and fluxes of Mg, Na, Fe and Al, followed in 2001 by rapidly declining concentrations and element fluxes. The subsequent 5 years saw more variable element ratios and strong depletions in K and Al. Most incompatible elements are released from the rock matrix stochiometrically, whereas some elements are enriched through vapor input from the magma (As, Pb, Zn). Most fluids have LREE enrichments relative to the rock matrix, but during periods of new magma intrusion the LREE enrichment decreases as does the magnitude of the negative Eu anomaly in the fluids. These observations are interpreted assuming early dissolution of plagioclase, olivine and volcanic glass that occurs during intrusion of new magma into the hydrothermal system. The high field strength elements are virtually immobile even in these hot acid fluids, with Nb and Ta more so than Hf and Zr. The mobility of U and Th in these fluids is comparable, at variance with Th behavior in neutral fluids. The local rivers and lakes of Copahue are fertilized by volcanic dissolved P, and most surface waters with pH < 3 have high levels of As. The acid fluids from Copahue may be surficial analogs for deep subduction fluids that evolve below zones of arc magma generation as well as for early Mars environments that are thought to have had large acid lakes.
The crater lake water from Maly Semiachik volcano in Kamchatka was used for the international analytical laboratory comparison of major and minor elements, and hydrogen, sulfur, and oxygen isotope data. Eight institutions participated in this program, giving analytical results of 9 major and 20 minor elements mainly by using ICP-AES for cations and IC for anions. Among the major elements, Na, Mg and Si showed coefficients of variation (CV) of 10% or more, whereas B, Al, Fe, Mn had coefficients less than 7%. The CV% of the minor elements Co, Cu, P, Cr, Pb was much greater (>30%) while the V analyses agreed well (<10%). Ti, Sr, Zn, and F were intermediate (between 10 and 20 CV%). The errors observed for these constituents are inherent to the methods applied: large dilutions and spectrometric interferences. Even the major anions such as Cl (>2000 ppm) and SO4 (>5000 ppm) gave considerable ranges (5.1 and 8.8 CV%, respectively) as did the obtained pH values (22 CV%). The measured δ18O of the water samples and δ34S of sulfate are in excellent agreement but the δD values had CV% of 8. Technical recommendations are presented to improve the analytical results for these elements with significant deviations from the mean values.
Data from 71 geothermal production intervals in 48 wells from the Salton Sea Geothermal System (SSGS) indicate that fluids in that system cluster into two distinct populations in terms of their salinity and their stable isotopic compositions. The distinctive, hot, hypersaline brine (typically >20 wt% total dissolved solids) for which the SSGS is known is overlain by a cooler (<260°C) fluid with distinctly lower salinity (typically <10 wt% total dissolved solids). Hypersaline brines have high and rather consistent 18O shifts produced by water-rock interaction and have a very narrow range in δD values. Low TDS fluids, on the other hand, show a wide range in both δD and δ18O. Production of both types of fluid from closely spaced geothermal wells in many regions of the SSGS indicates that a relatively sharp salinity interface exists over much of the field. The fluid interface typically cross-cuts sedimentary bedding but is consistently found where reservoir temperatures are approximately 260°C. At these temperatures, hypersaline brines have densities of approximately 1.0 gm/cm3, while the low TDS fluids have densities as low as 0.85 gm/cm3. This stable, density-stratified interface acts as a barrier to convective heat and mass transfer in the SSGS, isolating the hypersaline reservoir from overlying dilute fluids. A lithologic “cap” implied by previous SSGS models is unnecessary in such a stratified system since heat and mass transfer across the interface must occur by slow conductive, diffusional and interface mixing processes regardless of local permeability.
The origin of El Chichón volcano is poorly understood, and we attempt in this study to demonstrate that the Tehuantepec Ridge (TR), a major tectonic discontinuity on the Cocos plate, plays a key role in determining the location of the volcano by enhancing the slab dehydration budget beneath it. Using marine magnetic anomalies we show that the upper mantle beneath TR undergoes strong serpentinization, carrying significant amounts of water into subduction. Another key aspect of the magnetic anomaly over southern Mexico is a long-wavelength (~150 km) high amplitude (~500 nT) magnetic anomaly located between the trench and the coast. Using a 2D joint magnetic-gravity forward model, constrained by the subduction P–T structure, slab geometry and seismicity, we find a highly magnetic and low-density source located at 40–80 km depth that we interpret as a partially serpentinized mantle wedge formed by fluids expelled from the subducting Cocos plate. Using phase diagrams for sediments, basalt and peridotite, and the thermal structure of the subduction zone beneath El Chichón we find that ~40% of sediments and basalt dehydrate at depths corresponding with the location of the serpentinized mantle wedge, whereas the serpentinized root beneath TR strongly dehydrates (~90%) at depths of 180-200 km comparable with the slab depths beneath El Chichón (200-
220 km). We conclude that this strong deserpentinization pulse of mantle lithosphere beneath TR at great depths is responsible for the unusual location, singularity and, probably, the geochemically distinct signature (adakitic-like) of El Chichón volcano.
A bathymetric survey of Kawah Ijen crater lake was conducted by acoustic sounding in 1996 to compare the lake morphology with those measured in 1922, 1925 and 1938, and to calculate the present lake volume. Even though the lake experienced several hydrothermal eruptions, the maximum depth became shallower (182 m) than before (200 m), resulting in a reduced lake volume (3.0×107 m3).Fifty-two major and minor constituents including rare earth elements and polythionates (PT) of the lake waters at various depths were determined by ICP-AES, ICP-MS and HPLC, respectively. These ions except for several volatile elements are taken up by lake fringe through congruent dissolution of pyroclastics of Kawah Ijen volcano. Most ions are homogeneously distributed throughout the lake, although PT showed a considerable vertical variation. Rare earth elements (REE) in the Kawah Ijen water as well as those from other hyper-acidic crater lakes show distribution patterns likely due to the three rock dissolution (preferential, congruent and residual) types, and their logarithmic concentrations linearly depend upon the pH values of the lake waters.Using the PT degradation kinetics data, production rates of PT, injection rates of SO2 and H2S into the lake were estimated to be 114, 86 and 30 tons/day, respectively. Also travel time of the spring water at the Banyupahit Riverhead from Kawah Ijen was estimated to be 600–1000 days through the consideration of decreasing rates of PT. Molten sulfur stocks containing Sn, Cu, Bi sulfides and Pb-barite exposed on the inner crater slope were presumed to be extinct molten sulfur pools at the former lake bottom. This was strongly supported by the barite precipitation temperature estimated through the consideration of the temperature dependence of Pb-chlorocomplex formation.
The compositional characteristics of many geochemical systems which involve the interaction of natural aqueous solutions with minerals and gases are conveniently described using the following thermodynamic components: Cl−, SO4=, HS−, CO3=, H+, Na+, K+, Ca++, Mg++, Fe++, Zn++, Cu+, Al+++, SiO2 and H2O. A set of mass balance and mass action equations equal in number to the number of components plus the number of saturated minerals (and gases) is defined for a specified temperature, pressure and bulk composition. The mass balance equations include terms for minerals, gases and the molalities of aqueous complexes and dissociated species. This set of non-linear equations can be solved with the aid of a computer using'a Newton-Raphson technique. The calculation takes account of aqueous ion complexing, oxidation-reduction equilibria, activity coefficients, non-unit water activity and solid solutions. The use of H+, SO4=, HS− and H2O as components allows straightforward treatment of processes involving oxidation-reduction, evaporation, boiling and changes of total aqueous H+ due to hydrolysis, mineral reaction or temperature change. One product of this approach is a technique for calculating pH at high temperature from measurement of pH at room temperature.By linking a series of discrete overall heterogeneous equilibrium calculations in which incremental changes of bulk composition, temperature or pressure are made, dynamic geochemical processes can be modeled. Example calculations for two such processes are given. These are the heating of seawater from 25° to 300°C and the isothermal irreversible reaction of rhyolite with an aqueous solution at 250°C.
Chemical and Sr isotopic analyses have been made of waters from 16 geothermal sites in Iceland with particular reference to the systems at Reykjanes and Svartsengi for which compositions of geothermal sea water and fresh and hydrothermally-altered rocks have been compared. The alkalies display mixing relationships indicating a hydrothermal input of Rb and K to local meteoric and sea waters as do results for Sr and Ca involving high-temperature fluids. ratios of the geothermal waters of meteoric origin parallel those of associated rocks but are higher. Ratios for geothermal sea waters are 0.7042 (Reykjanes) and 0.7040 (Svartsengi), lower than for normal sea water (0.7092) because of leaching of Sr from rocks followed by partial removal into alteration minerals, of which epidote and chlorite may be most important. Consequently, associated hydrothermally-altered rocks have been subject to significant Sr isotopic contamination by sea water Sr raising ratios from 0.7032 for fresh rock to 0.7038–0.7042 (Reykjanes) and to 0.7039–0.7041 (Svartsengi). Altered basalt is only ~50% equilibrated isotopically with geothermal sea water, at a water/rock ratio of ~2, but is internally equilibrated whereas palagonitized rocks (water/rock ratio of 3 to 4) are close to Sr isotopic equilibrium with associated sea water but show significant internal Sr disequilibrium. Hydrothermal input is unlikely to be important in the oceanic mass balance of Sr but is likely to be highly significant in controlling the strontium isotopic composition of sea water.
The siliceous sinter deposits of El Tatio geothermal field in northern Chile have been examined petrographically and mineralogically. These sinters consist of amorphous silica (opal-A) deposited around hot springs and geysers from nearly neutral, silica-saturated, sodium chloride waters. Water cooling and evaporation to dryness are the main processes that control the opal-A deposition in both subaqueous and subaerial settings, in close spatial relation to microbial communities. All fingerprints of organisms observed in the studied sinter samples represent microbes and suggest that the microbial community is moderately diverse (cyanobacteria, green bacteria, and diatoms). The most important ecological parameter is the temperature gradient, which is closely related to the observed depositional settings: 1) Geyser setting: water temperature = 70–86 °C (boiling point at El Tatio: 4200 m a.s.l.); coarse laminated sinter macrostructure with rapid local variations; biota comprises non-photosynthetic hyperthermophilic bacteria. 2) Splash areas around geysers: water temperature = 60–75 °C; laminated spicule and column macrostructure, locally forming cupolas (< 30 cm); predominant Synechococcus-like cyanobacteria. 3) Hot spring setting: water temperature = 40–60 °C; laminated spicules and columns and subspherical oncoids characterize the sinter macrostructure; filamentous cyanobacteria Phormidium and diatoms (e.g., Synedra sp.) are the most characteristic microbes. 4) Discharge environments: water temperature = 20–40 °C; sinter composed of laminated spicules and oncoids of varied shape; cyanobacterial mats of Phormidium and Calothrix and diatoms (e.g., Synedra sp.) are abundant. El Tatio is a natural laboratory of great interest because the sedimentary macrostructures and microtextures reflect the geological and biological processes involved in the primary deposition and early diagenesis of siliceous sinters.
The ratio of 87Sr/86Sr was measured from different water samples of thermal/mineral (hot spring as well as crater lake) and meteoric origins, in order to specify the location and to verify the detailed model of a volcano-hydrothermal system beneath Zao volcano. The ratio showed a trimodal distribution for the case of thermal/mineral water: 0.7052–0.7053 (Type A, Zao hot spring), 0.7039–0.7043 (Type B, Okama crater lake and Shin-funkiko hot spring), and 0.7070–0.7073 (Type C, Gaga, Aone, and Togatta hot springs), respectively. However, in comparison, the ratio was found to be higher for meteoric waters (0.7077–0.7079). The water from the central volcanic edifice (Type B) was found to be similar to that of nearby volcanic rocks in their Sr isotopic ratio. This indicates that the Sr in water was derived from shallow volcanic rocks. The 87Sr/86Sr ratio for water from the Zao hot spring (Type A) was intermediate between those of the pre-Tertiary granitic and the Quaternary volcanic rocks, thus suggesting that the water had reacted with both volcanic and granitic rocks. The location of the vapor–liquid separation was determined as the boundary of the pre-Tertiary granitic and the Quaternary volcanic rocks by comparing the results of this strontium isotopic study with those of Kiyosu and Kurahashi [Kiyosu, Y., Kurahashi, M., 1984. Isotopic geochemistry of acid thermal waters and volcanic gases from Zao volcano in Japan. J. Volcanol. Geotherm. Res. 21, 313–331.].
Meaningful applications of water geothermometry to thermal springs in and around Lassen Volcanic National Park (LVNP) are limited to Growler Hot Spring and Morgan Hot Springs. Most hot springs located within LVNP are low-chloride, acid-sulfate waters associated with nearby steam vents. This type of hot-spring activity is characteristically found above vapor-dominated hydrothermal systems. These acid-sulfate waters are not generally useful for liquid chemical geothermometry, however, because their chemical compositions result from water-rock interaction at relatively shallow depths. Thermal waters at Drakesbad and in Little Hot Springs Valley have neutral-pH, low-Cl concentrations and have estimated Na-K-Ca and Na-Li geothermometer temperatures close to measured spring temperatures of 65 to 95°C. Hot-spring waters located south of LVNP at Growler Hot Spring, Morgan Hot Springs, and in the south-central part of LVNP in the Walker “O” No. 1 well at Terminal Geyser are rich in chloride and yield calculated geothermometer temperatures between 220 and 230°C. These thermal waters probably originate within a zone of upflow of high-enthalpy fluid inside LVNP and cool conductively during lateral flow to the south and southeast.
El Chichón crater lake appeared immediately after the 1982 catastrophic eruption in a newly formed, 1-km wide, explosive crater. During the first 2 years after the eruption the lake transformed from hot and ultra-acidic caused by dissolution of magmatic gases, to a warm and less acidic lake due to a rapid “magmatic-to-hydrothermal transition” — input of hydrothermal fluids and oxidation of H2S to sulfate. Chemical composition of the lake water and other thermal fluids discharging in the crater, stable isotope composition (δD and δ18O) of lake water, gas condensates and thermal waters collected in 1995–2006 were used for the mass-balance calculations (Cl, SO4 and isotopic composition) of the thermal flux from the crater floor. The calculated fluxes of thermal fluid by different mass-balance approaches become of the same order of magnitude as those derived from the energy-budget model if values of 1.9 and 2 mmol/mol are taken for the catchment coefficient and the average H2S concentration in the hydrothermal vapors, respectively. The total heat power from the crater is estimated to be between 35 and 60 MW and the CO2 flux is not higher than 150 t/day or ~ 200 gm− 2 day− 1.
Rare earth element concentrations have been measured in hydrothermal solutions from geothermal fields in Italy, Dominica, Valles Caldera, Salton Sea and the Mid-Atlantic Ridge. The measured abundances show that hydrothermal activity is not expected to affect the REE balance of either continental or oceanic rocks. The REE enrichment of the solutions increases when the pH decreases. High-temperature solutions (>230°C) percolating through different rock types may show similar REE patterns.
Lake Caviahue (northern Patagonia, Argentina) is a large glacial lake acidified by volcanic fluids from Copahue volcano. The lake and the feeding rivers were sampled annually from 1997 till early 2006, including the eruptive period of 2000. Lake Caviahue waters evolved over time, with the most concentrated waters in 2000 during the eruptive period, followed by gradual dilution that was interrupted by renewed acidification in 2003–2004. Inversion of the lake water data and application of a dynamic non-steady state model for the lake provides our best quantitative estimates for the variation in element fluxes over the 9-year period. The model flux results agree well with most of the measured fluxes. The Copahue hydrothermal system had gently declining element fluxes between 1997 and mid-1999, although the lake was still becoming more concentrated. About 2–3 months before the 2000 eruption, element fluxes increased strongly, but the hydrothermal fluxes almost shutoff directly after the main eruptive events. The fluxes of several elements recovered post-2001, with an increase in element fluxes in 2003–2004; the lake became more dilute between 2004 and 2006. The intrusion of new magma into the hydrothermal system just prior to the 2000 eruption led to enhanced water rock interaction, with higher concentrations of the rock forming elements in the fluids, and the hot spring flow rate increased as a result of the higher pressure in the reservoir. The fluids became saturated in alunite and jarosite, and they were already saturated with anhydrite. Precipitation of these minerals possibly led to a decreased permeability of the hydrothermal reservoir, leading to the strongly reduced element fluxes just after the eruption. In addition, K, Al and S were retained in the newly precipitated minerals as well, further diminishing their export. The acidification in 2003–2004 may have resulted from a new small intrusion of magma or resulted from seismic activity that created new permeability and fresh rock surfaces for water rock interaction. The volcano is a significant source of toxic trace elements such as F, As, B and Li as well as a nutrient (P) for the local watershed. Monitoring of the hydrothermal fluids in the river that drains Copahue, especially the S/Cl, Mg/Cl and Mg/K values as well as the magnitude of the element fluxes would provide the best information for eruption forecasting for this volcano.
Isotopic measurements (Sr, O, D) on formation waters from the Alberta Basin have been made, covering a stratigraphic range from Devonian to Upper Cretaceous. These measurements, combined with chemical compositional trends, give evidence for two distinct water regimes. One hydrological regime is composed of waters hosted in Devonian-Lower Cretaceous reservoirs, the other waters from Upper Cretaceous and younger sedimentary rocks. The two regimes are separated by a regional transgressive shale in the Colorado Group, the Second White Speckled Shale Formation.