Joaquin Ruiz

• Doctor of Philosophy
• University of Arizona

The concentration of potentially toxic elements (PTE) and the isotope compositions (⁸⁷Sr/⁸⁶Sr, δ³⁴S, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios) were determined in spring water, sulfide minerals, and rocks samples to evaluate spring water used for human consumption in the historical mining region of Taxco de Alarcón, southern Mexico. The spri...

Concentrations of Hg, Sb and the related potentially toxic elements (RPTEs) As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn were determined in tailings from the Hg–Sb mining region of Huitzuco, Guerrero (southern Mexico) to evaluate their impact on urban soils and shallow groundwater. Tailings are entirely composed of fragments from the ore-hosting Mo...

The Archean-Paleoproterozoic Crixás greenstone belt is one of the most important components of the Crixás-Goiás Domain, the oldest crustal segment of the Central Brazil Goiás Massif. This gold-bearing greenstone comprises amphibolite facies ultramafic-mafic metavolcanic rocks overlaid by a low-grade metasedimentary succession associated with rocks...

The Xolapa Complex of southern Mexico preserves evidence of its connection with the Chortís Block of Central America. Orthogneisses yielded U-Pb protolith ages from 172 to 169 Ma and paramigmatites are dated at 217 Ma. El Salitre and the Amatlán granitoids show crystallization ages of 65 and 59–57 Ma, respectively. In central Xolapa, diatexites hav...

The eastern Pontide tectonic belt (EPTB) contains greater than 350 identified Kuroko type volcanogenic massive sulfide deposits/mineralization/occurrences (VMSD). The deposits are associated with Late Cretaceous felsic volcanics consisting mainly of dacitic and rhyolitic lavas and pyroclastics that outcrop within a narrow zone running parallel to t...

15 16 Recent analytical developments in the field of mass spectrometry have made possible accurate 17 measurements of "non-traditional" isotopic ratios of elements such as Fe, Cu, Ag, Sn, Sb and Hg. 18 The stable isotopes of these elements do not have any radioactive parents, but their ratios undergo 19 limited fractionation from various causes, mo...

The concentration of As, Pb, Cd, Zn, Fe, Mn, and Cu and the Sr and Pb isotopic compositions were determined in four species of the vascular epiphyte Tillandsia (T. caput medusae, T. ionantha, T. recurvata, and T. sp), to evaluate their capacity to biomonitor the air quality and the sources of lithogenic particles and toxic elements in a severely co...

Land-atmosphere interactions at different temporal and spatial scales are important for our understanding of the Earth system and its modeling. The Landscape Evolution Observatory (LEO) at Biosphere 2, managed by the University of Arizona, hosts three nearly identical artificial bare-soil hillslopes with dimensions of 11 × 30 m2 (1 m depth) in a co...

The present work contributes with new data to better understand the geology and spatial distribution of the alteration and mineralization events, as well as new U–Pb zircon ages, that allow elucidating the magmatic history of the La Caridad Vieja mineral deposit, which is part of the porphyry Cu–Mo system from La Caridad mine, northwest Mexico. Min...

Discharge of Acid Mine Drainage (AMD) produced within flooded mines is a major environmental issue in most polymetallic mining sites severely impacting nearby natural resources and producing a serious menace to the ecosystem and humans. The identification of both natural and anthropological factors influencing the bioavailability of toxic elements...

Mining is an important activity in Mexico; however, despite its economic benefits, it carries potential environmental risks, including mine spills. On August 6, 2014, ~ 40,000 cubic meters of copper sulfate acid solution was spilled from the Tinajas 1 dam of the Buenavista del Cobre mine in Cananea, Sonora, northwestern Mexico. The solution was dir...

Temporal trends in granitoid chemistry and thermometry constrain major global changes in magmatism, tectonism or crustal thickness in the continents. Our study relies on zircon geochronology and trace element geochemistry on four new detrital rocks (two modern sediments and two Archean metasedimentary rocks) and a global compilation of published si...

La cooperación internacional en el ámbito de la ciencia es una herramien- ta de innovación y desarrollo. El Consorcio Arizona-México para Ambien- tes Áridos (Cazmex) contribuye a la consolidación científica, tecnológica y educativa, mediante el apoyo de proyectos relacionados con el medio ambiente, cambio climático y desarrollo social sustentable e...

Copper mining in Tongling has occurred since the Bronze Age, and this area is known as one of the first historic places where copper has been, and is currently, extracted. Multiple studies have demonstrated, through concentrated work on soils and waters, the impact of mining in the area. Here we present copper isotope values of 13 ore samples, thre...

A redox reaction in which Sn 2+ oxidizes to Sn 4+ is thought to occur during the precipitation of cassiterite (SnO 2) and stannite (Cu 2 FeSnS 4) from high-temperature hydrothermal solutions. In four stanniferous regions with differing mineralization environments (South Dakota, U.S.A.; Cornwall, England; Erzgebirge, Germany/Czech Republic; Andean t...

Understanding the process interactions and feedbacks among water, porous geological media, microbes, and vascular plants is crucial for improving predictions of the response of Earth’s critical zone to future climatic conditions. However, the integrated coevolution of landscapes under change is notoriously difficult to investigate. Laboratory studi...

The environmental fate of lead derived from traffic paint has been poorly studied in developing countries, mainly in arid zones. For this purpose, a developing city located in the Sonoran desert (Hermosillo, Mexico), was chosen to conduct a study. In this paper the lead chromate (crocoite) sources in atmospheric dust were addressed using a combinat...

A redox reaction in which reduced Sn 2+ oxidizes to Sn 4+ is thought to occur during the precipitation of cassiterite (SnO2) and stannite (Cu2FeSnS4) from high-temperature hydrothermal solutions. In four stanniferous regions with differing mineralization environments (South Dakota, USA; Cornwall, England; Erzgebirge, Germany/Czech Republic; Andean...

Archaeologists have long suggested that prehispanic states in Mesoamerica acquired turquoise through long-distance exchange with groups living in what is now the American Southwest and adjacent parts of northern Mexico. To test this hypothesis, we use lead and strontium isotopic ratios to investigate the geologic provenance of 43 Mesoamerican turqu...

The Xolapa complex of southern Mexico is a crustal block, the age and nature of which are still unresolved. Its origin and tectonic evolution enclose critical clues about the geodynamic evolution of southern Mexico and the detachment and translation of the Chortis block of Central America and, hence, about the evolution of southern North America at...

Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m(3) of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6-5.1 mg C m(-2)...

The concentration and isotopic composition of lead in the blood of forty seven women of reproductive age (15–45 y) exposed to multiple sources in two rural communities of the mining region of Taxco, Guerrero in southern Mexico were determined in order to identify specific contributing sources and their apportionment and to trace probable ingestion...

The extent of weathering incongruency during soil formation from rock controls local carbon and nutrient cycling in ecosystems, as well as the evolution of hydrologic flow paths. Prior studies of basalt weathering, including those that have quantified the dynamics of well-mixed, bench-scale laboratory reactors or characterized the structure and int...

Multi-isotope (H, O, S, Sr, Pb) systems coupled with conventional (major and trace element) hydrogeochemical analysis were applied to determine the origin of water, to model water-rock-tailings interactions and for source apportionment of sulfur and associated toxic metals in the mining region of Taxco, Guerrero in southern Mexico. Oxygen and H iso...

The Cananea mining district constitutes the cluster of deposits that is richest in Cu in Mexico, which, together with the porphyry copper deposits from southern Arizona and western New Mexico, is part of one of the largest copper provinces on Earth. The main mineralized localities within the district are the Buenavista del Cobre, Mariquita, Milpill...

High-grade basement massifs exposed in the northern Andes and the buried basement of the adjacent Putumayo foreland basin contain a record of Amazonia's involvement in the supercontinent Rodinia. Metasedimentary granulites and orthogneisses, strongly deformed during at least one metamorphic episode dated at ca. 0.99 Ga, provide critical information...

The archaeological record shows that turquoise was widely mined and highly valued by pre-Hispanic societies in the southwestern United States, and it has long been assumed that much of the turquoise noted in ancient Mesoamerica was traded from this region. However, little is understood about the acquisition and exchange of turquoise by Native Ameri...

Zinc (Zn) is essential for development, growth, and reproduction. The Mexican government subsidizes micronutrient-fortified milk for risk groups, with positive effect on the targeted groups’ plasma Zn level, inferring a good absorption is achieved although it has not being measured. The aim of this study was to determine the impact of micronutrient...

Copper isotope signatures in waters emanating from mineralized watersheds provide evidence for the source aqueous copper in solution. Low-temperature aqueous oxidation of Cu sulfide minerals produces significant copper isotopic fractionation between solutions and residues. Abiotic experimental data of fractionation (defined as Δliquid-solid ‰= δ65C...

Lead isotopic ratios of cassiterite, the dominant ore of tin, evolve after crystallization through decay of uranium (U) and thorium (Th) to lead (Pb), due to the relatively elevated U/Pb ratios of this mineral. We show that the Pb isotopic ratios of smelted tin at Rooiberg, South Africa, form an isochron with a model age that matches the known geol...

U–Pb geochronology of baddeleyite (ZrO2) is an increasingly used tool in the Earth and planetary sciences for determining the crystallization and emplacement ages of mafic igneous rocks. Additionally, baddeleyite has a strong affinity for hafnium and preferentially excludes the REE's, making it an important repository of Hf isotopic compositions, w...

New U-Pb detrital zircon data of metasedimentary rocks of the Aguapeí Group, SW Amazonian Craton, are presented in this work. Three samples were analyzed by ICPMS laser ablation in order to estimate the age of the source areas of the sediments and the maximum depositional age of the basin. The samples show an Archean age of 2515 Ma not yet reported...

Re-Os analyses of pyrite from the Pueblo Viejo high-sulfidation epithermal deposit (both Monte Negro and Moore ore zones) yield an isochron age of 111.9 ± 3.7 Ma and initial 187Os/188Os ratio of 0.22 ± 0.18 (mean square of weighted deviates = 84, n = 21). Isochrons grouped by pyrite setting (layered versus vein) or locations yield ages within uncer...

Manganese oxide mineralization on the eastern coast of Baja California Sur is intimately related to the Neogene tectonic evolution of the Gulf of California. Manganese is closely associated with the Cu-Co-Zn mineralization of the Boleo district and nearby deposits of Santa Rosalía region and Concepción peninsula. Trace element and rare earth elemen...

Manganese oxide mineralization on the eastern coast of Baja California Sur is intimately related to the Neogene tectonic evolution of the Gulf of California. Manganese is closely associated with the Cu-Co-Zn mineralization of the Boleo district and nearby deposits of Santa Rosalía region and Concepción peninsula. Trace element and rare earth elemen...

Introduction Sampling and Analysis Results and Discussion Conclusions

Paleozoic sedimentary sequences of northern South America have the potential of being important oil- and gas-producing horizons, and are recently becoming the focus of active resource exploration by the energy industry. However, given the prolific character of the Meso- Cenozoic plays in the region, the Paleozoic systems have commonly been overlook...

The U–Pb (LA-MC-ICPMS) geochronology of Xolapa metasedimentary rocks from Tierra Colorada, Guerrero to Puerto Ángel, Oaxaca in southern Mexico reveals that their protoliths accumulated in two distinctive cycles of sedimentation, one of Early Jurassic age and another of Late Cretaceous age. These ages are younger than thought and demonstrate that Xo...

This study analyzes Re and Os contents of Au rich sulfides from the Carbon Leader (Tau Lekoa and Mponeng), the VCR (Mponeng and Tau Lekoa), and the Black Reef (Modder East), as well as native Au in the Carbon Leader, to further investigate the detrital (placer), modified detrital (placer), and hydrothermal models for the source of Au in mines from...

The Mariquita porphyry Cu and Lucy Cu–Mo deposits are located in the western section of the Cananea porphyry copper district in northwestern Mexico. Four hydrothermal stages are found in Mariquita: stage I is composed of quartz–pyrite–biotite–magnetite; stage II corresponds to orthoclase–quartz; stage III consists of unidirectional veinlets of quar...

Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechani...

A significant proportion of the copper in the Cañariaco Norte porphyry copper deposit in northern Peru occurs in chalcocite and covellite-rich veins and disseminations that exist from the surface to depths greater than 1 km. The overall range of Cu isotopic ratios of 42 mineral separates from Cañariaco varies from −8.42 to 0.61 ‰, with near-surface...

[1] Apatite is a common U-bearing accessory mineral with a U-Pb closure temperature of ∼500°C, making U-Pb dating of apatite a potentially valuable thermochronometer. However, its low U concentration and tendency to incorporate common lead has limited widespread application to destructive isotope dilution methods. We overcome previous limitations b...

Archaeological evidence has become an increasingly important component of efforts to identify the route of the Francisco Vázquez de Coronado expedition through northern Mexico and the southwestern United States (1540–1542). Here, we report the first high-precision lead isotopic measurements of artifacts from two archaeological sites with strong mat...

Outcrops of late Meso- to early Neoproterozoic crust in northwestern South America are restricted to isolated exposures of basement inliers within the northern Andes of Colombia, Peru and Venezuela. However, evidence for the existence of an autochthonous Stenian–Tonian belt in northern Amazonia that is undisturbed by Andean orogenesis has not been...

New major- and trace-element and radiogenic Sr and Nd data from granitic rocks help to characterize the geochemical composition of the Coastal Sonora batholith, which represents the westernmost portion of the Laramide Magmatic arc (~80–40 Ma) in Mexico. Compared with more inland-located regions of the arc in central and eastern Sonora (Inner Granit...

Terra Nova, 23, 26–34, 2011 The timing of orogeny in the northern Andes and the mechanism driving it are still debated. We have studied the age, composition and provenance of granitoids and sandstones of the Santa Marta Massif and Rancheria Basin, northern Colombia, to relate deep-seated and surface tectonic processes attending the Late Cretaceous–...

Molybdenum is an economically important subproduct of North Chilean porphyry-type deposits, and thus spatial and temporal distribution of molybdenite as the primary Mo-bearing mineral in the Escondida and Escondida Norte deposits were characterized using several mineralogical and chemical techniques and the Re-Os dating method. Molybdenum is distri...

The Late Paleozoic to Triassic tectonics of northwestern South America have major implications for the understanding of Laurentia–Gondwana interactions that formed Pangea, and the origin of several tectonostratigraphic terranes dispersed by the break-up of this supercontinent during the formation of the Caribbean. Two mylonitic and orthogneissic gr...

Metamorphosed volcano-sedimentary rocks accreted to the northern South American continental margin are major vestiges of the Caribbean oceanic plate evolution and its interactions with the continent. Selected whole rock geochemistry, Nd–Sr isotopes and detrital zircon geochronology were obtained in metabasic and metasedimentary rocks from the Santa...

La Sierra Madre del Sur, un arco magmático del Mesozoico–Cenozoico localizado en el sur de México, fue estudiado usando geocronología de U–Pb en circones. Plutones no deformados a ligeramente deformados de dos transectos localizados en el límite entre los terrenos Guerrero y Xolapa fueron muestreados, buscando precisar la historia magmática, natura...

Chile is a major world producer of copper, most of which occurs in base-metal porphyry and in manto deposits. A fundamental difference between these two types of deposits is the relative importance of intrusions spatially associated with the mineralization. The porphyry deposits are set within Mesozoic to Tertiary intrusive complexes. The manto-typ...

Apatite is a common U-bearing accessory mineral in magmatic, sedimentary, and metamorphic rocks, with a U-Pb closure temperature of 450-550°C, making U-Pb dating of apatite a potentially valuable thermochronometer. However, the low U concentration in apatite and its tendency to incorporate high amounts of common lead has previously limited the accu...

Accurate orogenic models are nedded to reconstruct complex tectonic histories of long lived convergent margins. Integrated zircon U-Pb geochronology on igneous, sedimentary and metasedimentry rocks within single crustal domains is a powerful tool, as it can be used to trace the timing of rock forming events, magmatic style and episodity, and identi...

U/Pb LA‐MC‐ICP‐MS zircon ages and whole‐rock geochemistry from a biotite granitoid, recovered at ∼2.1 km depth from the Ranchería‐2 well in the Baja Guajira basin, southern Caribbean region, reveal the existence of a ca. 70 Ma silicic plutonic event. This granitoid intrudes ca. 76–80 Ma intraoceanic arc fragments and continental margin sediments th...

Correlation of deformational phases and thermal events in the Acatlán Complex permits definition of nine major tectonic events. Seven events are related to the evolution of the Iapetus and Rheic oceans. By the Early Ordovician, the Xayacatlán suite of Laurentian affinity was metamorphosed to eclogite facies and exhumed before colliding with the El...

New thermobarometric and U/Pb and 40Ar/39Ar geochronologic data coupled with ages obtained from the Acatlán Complex, the basement of the Mixteco terrane of southern Mexico, reveal the existence of three distinctive high-pressure metamorphic events of early to middle Paleozoic age, each recorded in a separate lithologicai suite. Xayacatlán suite ecl...

This study integrates U‐Pb zircon geochronology (from LAM‐ICP‐MS, SHRIMP, and TIMS) with Nd isotopic data from orthogneisses and metasedimentary rocks of the pre‐Mesozoic basement of the eastern Peruvian Andes to provide new information on the tectonic evolution and Neoproterozoic‐Paleozoic paleogeography of this segment of the proto‐Andean margin....

The Sierra Madre del Sur, a Mesozoic–Cenozoic magmatic arc in southern Mexico, was studied using U–Pb zircon geochronology. Undeformed to slightly deformed plutons from two transects were sampled at the limit between the Guerrero and Xolapa terranes, in order to constrain the magmatic history, nature of the basement and terrane boundaries. Four sam...

The Sierra Madre del Sur, a Mesozoic-Cenozoic magmatic arc in southern Mexico, was studied using U-Pb zircon geochronology. Undeformed to slightly deformed plutons from two transects were sampled at the limit between the Guerrero and Xolapa terranes, in order to constrain the magmatic history, nature of the basement and terrane boundaries. Four sam...

U–Pb zircon geochronology is hampered by problems acquiring meaningful geologic ages on zoned grains that retain isotope signatures from multiple growth or thermal events. We present a new method using laser ablation-multicollector-inductively coupled plasma-mass spectrometry to overcome complications associated with intricately zoned zircon crysta...

U–Pb detrital zircon studies in the Rio Fuerte Group, NW Mexico, establish its depositional tectonic setting and its exotic nature in relation to the North American craton. Two metasedimentary samples of the Rio Fuerte Formation yield major age clusters at 453–508Ma, 547–579Ma, 726–606Ma, and sparse quantities of older zircons. The cumulative age p...

Medium-to high-grade metasedimentary rocks are exposed as isolated domains in mostly metaigneous crystalline rocks of the Chiapas Massif Complex (CMC), which forms the basement of the southern Maya Block, southeastern Mexico. Laser ablation multicollector inductively coupled plasma mass spectrometry U-Pb isotope analyses on inherited detrital zirco...

The La Voluntad porphyry Cu–Mo deposit in Neuquén, Argentina, is one of several poorly known porphyry-type deposits of Paleozoic to Early Jurassic age in the central and southern Andes. Mineralization at La Voluntad is related to a tonalite porphyry from the Chachil Plutonic Complex that intruded metasedimentary units of the Piedra Santa Complex. F...

Hypotheses concerning processes and timing of hydrothermal sulfide mineralization in the central Pennsylvanian Appalachians utilize Mississippi Valley-type (MVT) models with Paleozoic ages. To examine this model, we studied sulfide-bearing veins in the Skytop sulfide occurrence that contain pyrite Pyrite occurs in two separate structural domains as...

The manganese ores in the Santa Rosalía region, western Mexico, are mainly stratiform horizons or mantos, constrained to the initial stages of sedimentary cycles of the Miocene Boléo Formation. The manganese mineralization is generally restricted to isolated paleo-basins and related to NW–SE faults formed during the early stages of the opening of t...

Four main stages of alteration and mineralization are present at La Caridad, Sonora, Mexico. in stage 1, quartz veins are associated with orthoclase-anhydrite-biotite hydrothermal alteration within the La Caridad intrusive complex and with pervasive biotitization in andesites and diorites. A zone of propylitic alteration surrounds this biotitic zon...

U-Th-Pb geochronology by laser ablation-multicollector-inductively coupled plasma-mass spectrometry initiated during the mid to late 1990s as a reconnaissance tool, capable of generating ages of only moderate precision from relatively large volumes of zircon. New developments in instrumentation and experimental methodology, as described herein and...

Available from the Minor Planet Center.

Olivine and spinel compositions, major elements (including ferric and ferrous iron), S, Re and Os contents have been measured for a suite of primitive (most >6 wt% MgO) basalts from the Trans Mexican Volcanic Belt (TMVB), including the western Mexican volcanic belt, the Michoacan-Guanajuato Volcanic Field, Sierra Chichinautzin, Pico de Orizaba regi...

Semi-arid and and rivers typically exhibit increasing salinity levels downstream, a trend often attributed to irrigated agriculture, primarily due to evapotranspiration. In contrast, the results of our investigations in one salinized river suggest that geological sources of salt added by groundwater discharge are more important than agricultural ef...

The life cycle of an intra-oceanic terranemincludes different phases and styles of magmatic growth, accretion with other terranes and translation before reaching a continental margin. In order to unveil the nature of these phases in crystalline rocks from northern Colombia, U/Pb LA-MC-ICP-MS detrital geochronology and whole rock geochemical data we...

Late Jurassic-Cretaceous arc-related volcaniclastic rocks from the southern Guerrero and western Mixteca terranes of Mexico were analyzed by U-Pb detrital zircon geochronology (laser ablation-multicollector-inductively coupled plasma-mass spectroscopy) to place constraints on the depositional history and provenance of the rocks. Pre-Middle Jurassic...

We report on the major and trace element composition and homogeneity of NIST (National Institute of Standards and Technology) glass standard reference materials 611, 612, 614, and 1834 for use as microanalytical trace element standards in laser ablation-inductively coupled plasma-mass spectrometry. The four analyzed NIST glasses were not designed a...

Single fluid inclusions in quartz from a Pb-Zn-Ag carbonate replacement deposit were selected for trace element determination by laser ablation ICP-MS. Spikes in element intensities were noted between first breached fluids versus subsequent analyses, suggesting that accurate element concentrations may not be determined in smaller fluid inclusions w...

For the trace element analysis of gold by laser ablation ICP-MS, external calibration samples of differing matrix composition have been used in previous studies. Data presented here suggest that even for calibration samples and unknowns with closely-matched matrices, discrepancies arise due to variations in the coupling behaviour of the laser with...

The Jalisco Block is a fault-bounded crustal fragment, located along the western edge of the Trans-Mexican Volcanic Belt of west-central Mexico, and it forms part of the Triassic-Jurassic Guerrero terrane. Because of its extensive Miocene-Quaternary volcanic cover and Early Cretaceous-Tertiary intrusions, little is known about its Pre-Tertiary hist...

We measured iron isotopic composition of surface (10–20 cm) and subsurface (50–70 cm) basaltic soil horizons from the Island of Maui along a climate gradient (MCG) ranging from 2.2 to 4.2 m mean annual precipitation (MAP). All soil forming factors except climate were conserved. The MCG has a documented decrease in Fe with increasing rainfall that i...

La Isabela, the first European town in the New World, was established in 1494 by the second expedition of Christopher Columbus but was abandoned by 1498. The main motive for settlement was to find and exploit deposits of precious metals. Archaeological evidence of silver extraction at La Isabela seemed to indicate that the expedition had located an...