Burkhard Schmidt

Burkhard Schmidt
University of Göttingen | GAUG · Department of Experimental and Applied Mineralogy

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Publications (93)
Article
Full-text available
Reaction rims contain a wealth of information that can be used to decipher the P-T-t-X history of metamorphic and metasomatic rocks. One of the most important parameters that controls reaction rim growth is the presence of volatiles, which can affect rim thicknesses, phase stabilities and the development of rim microstructures. In this study, react...
Article
A new method for measurements of high-CO2 concentrations in silicate glasses was established using micro–attenuated total reflectance (µ-ATR) Fourier transform infrared (FTIR) spectroscopy in the mid-IR (MIR) region. We studied two glass/melt compositions, namely leucitite and granite, to cover samples in which CO2 is dissolved as carbonate ions (C...
Article
Full-text available
Using the diffusion couple technique, diffusion of CO2 in a leucititic melt from the Colli Albani Volcanic District in Italy was investigated at temperatures between 1200 and 1350 ∘C in an internally heated pressure vessel at 300 MPa. To examine the effect of dissolved H2O in the melt, experiments were performed for a nominally dry melt (0.18 ± 0.0...
Article
Full-text available
Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the diffusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having different Li and B contents; thes...
Conference Paper
Full-text available
Carbonated hydroxy-apatite (CHAP) was experimentally synthesized in batch-type setups by mixing of calcium (Ca)-and phosphate-bearing aqueous solutions and the transformation of calcite powder in aqueous solution between 11°and 65°C (Gussone et al., 2020). Compositional changes of the experimental solution and solid phase products were followed by...
Article
Full-text available
Minerals for the dead: gypsum and hematite in pre-hispanic burials of southern Patagonia. The present work aims to analyze the mineralogy and geochemistry of the ochre associated with human remains of about 3800 years old, located in a cave of the Pali Aike volcanic field (Santa Cruz). Raman spectroscopy shows a clear presence of gypsum and hemat...
Article
Carbonated hydroxy-apatite (Ca10-b(NH4,K,Na)2b(PO4)6-y[(CO3)2x+(3/2)y(OH)2–2x]; CHAP) was synthesized in batch-type experiments by mixing of calcium (Ca)- and phosphate-bearing aqueous solutions and the transformation of calcite powder in aqueous solution between 11° and 65 °C. Compositional changes of the mother solution and solid phase products w...
Article
Full-text available
Diffusion chronometry on zoned crystals allows constraining duration of magmatic evolution and storage of crystals once temperatures are precisely known. However, non-isothermal diffusion is common in natural samples, and thus timescales may not be determined with confidence while assuming isothermal conditions. The "non-isothermal diffusion increm...
Article
Full-text available
Quartz is able to incorporate trace elements (e.g., H, Li, Al, B) depending on the formation conditions (P, T, and chemical system). Consequently, quartz can be used as a tracer for petrogenetic information of silicic plutonic bodies. In this experimental study, we provide the first data set on the OH defect incorporation in quartz from granites ov...
Article
Diffusion chronometry on zoned crystals allows constraining duration of magmatic evolution and storage of crystals once temperatures are precisely known. However, non-isothermal diffusion is common in natural samples and thus, time-scales may not be determined with confidence while assuming isothermal conditions. The “Non-isothermal Diffusion Incre...
Article
The present work aims at understanding the composition and source of the red rock art pigments used by hunter-gatherer groups during the late Holocene in southern Patagonia (southernmost South America), by combining micro X-ray fluorescence (μXRF) and Raman spectroscopy. In the first place, μXRF geochemical data do not reveal any significant compos...
Article
Full-text available
The solubility of CO2 and H2O in phonolitic and leucititic melts from Vesuvius and Colli Albani was investigated experimentally at 1250 °C and pressures between 50 and 300 MPa as a function of CO2–H2O fluid composition. Quenched glasses were analyzed for their volatile contents by thermogravimetry, carbon–sulfur analysis, and Fourier transform infr...
Article
Clumped isotope data from carbonated apatite from in vivo and in vitro samples are presented to refine the relationship between mineral growth temperature and carbonate clumped isotopic composition (Δ 47 ). Δ 47 , δ ¹⁸ O and δ ¹³ C data were obtained from phosphoric acid digestion (T = 110 °C) of chemically untreated teeth from an African elephant,...
Conference Paper
Full-text available
Diffusion chronometry on zoned crystals allows constraining duration of magmatic evolution and storage of crystals once temperatures are precisely known. However, non-isothermal diffusion is the rule in natural samples and thus, timescales cannot be determined with confidence while assuming isothermal conditions. Therefore, we experimentally test t...
Article
Full-text available
Two sample preparation techniques (ultrafine powder pellet and flux‐free fusion glass) for LA‐ICP‐MS bulk analysis of granitoids were compared. Ultrafine powder particles produced by wet milling were characterised as d50: ~ 1.0 μm, d90: ~ 5.0 μm. Agate abrasion (balls and vial) during wet milling affects only SiO2 measurements and is negligible for...
Article
Full-text available
Background Meniscal calcification is considered to play a relevant role in the pathogenesis of osteoarthritis of the knee. Little is known about the biology of acetabular labral disease and its importance in hip pathology. Here, we analyze for the first time the calcification of the acetabular labrum of the hip (ALH) and its relation to hip cartila...
Conference Paper
Full-text available
Diffusion chronometry serves as an essential tool in constraining magmatic evolution and storage. Diffusion rates vary significantly for a small change in temperature. For crystals growing in natural conditions in a dynamically evolving magma reservoir, timescales of diffusion are difficult to precisely constrain using isothermal diffusion modellin...
Article
Lipid biomarkers are commonly used for tracking life through Earth’s history and are also gaining in importance in the search for extraterrestrial life. However, some lipids may also be formed in-situ via abiotic Fischer-Tropsch-type (FTT) reactions. These processes have been considered as a source of prebiotic organic matter. Here we report on a F...
Article
The field of noble gases chemistry has witnessed amazing advances in the last decade with over 100 compounds reported including Xe oxides and Xe–Fe alloys stable at the pressure-temperature conditions of planetary interiors. The chemistry of Xe with planetary materials is nonetheless still mostly ignored, while Xe isotopes are used to trace a varie...
Article
Full-text available
The estimation of the peak metamorphic temperature by Raman spectroscopy of carbonaceous material (RSCM) is influenced by several bias sources grouped in measuring conditions, spectral processing and sample heterogeneity. The measuring conditions (selected excitation wavelength) and the operator bias during spectral processing have a pronounced imp...
Article
Full-text available
The volatile content in magmas is fundamental for the triggering and style of volcanic eruptions. Carbon dioxide, the second most abundant volatile component in magmas after H2O, is the first to reach saturation upon ascent and depressurization. We investigate experimentally CO2-bubble nucleation in trachybasalt and trachyte melts at high temperatu...
Article
Lacustrine sediments of impact craters form valuable climate archives, although chemical evolution and changes in the catchment area potentially superimpose, distort, or obliterate primary climate signals. The 15 Ma Nördlinger Ries in southern Germany, one of the most intensively studied terrestrial impact structures, harbors a well-preserved but c...
Article
We report the first experimental study on CO2 bubble nucleation and growth in silicate magmas in response to pressure release. The starting materials were nominally anhydrous trachyte and trachybasalt glasses that were CO2 saturated at 1200°C and 300 MPa for at least 48h under oxidizing conditions. These starting glasses were doped with diverse cry...
Conference Paper
Full-text available
This study focused on the role of CO 2 on the dynamics of magma ascent by the determination of its homogeneous and heterogeneous bubble nucleation in K-rich silicate melts. The starting materials were nominally anhydrous trachyte and trachybasalt glasses that were CO 2 saturated at 1200°C and 300 MPa for at least 48h under oxidizing conditions. The...
Article
Transitional melts, intermediate in composition between silicate and carbonate melts, form by low degree partial melting of mantle peridotite and might be the most abundant type of melt in the asthenosphere. Their role in the transport of volatile elements and in metasomatic processes at the planetary scale might be significant yet they have remain...
Conference Paper
Full-text available
Various types of hydrous silicate minerals are commonly found in the earth's crust and mantle, which may contain important information on fluid transport in subduction zones and metamorphic processes. Hydrous silicate minerals and glasses were analysed by laser ablation ICPMS to assess their potential as geochemical tracers and to study the potenti...
Article
Viscosity experiments were conducted to investigate the effect of Li2O on the viscosity of pegmatite forming melts and the possible difference to K2O. The individual effects of Li2O and K2O on melt viscosity were investigated by adding the same molar proportion of both components to a starting composition representing natural pegmatite forming melt...
Article
Palaeoproterozoic grano-dioritic rocks of the island of Äspö exhibit several mineralized fracture generations mainly filled by quartz, calcite, fluorite and/or epidote. Manganese-rich calcite fractures of probably Palaeozoic age are related to younger, possibly Pleistocene/Holocene cracks formed during the last ice age and successive crustal uplift...
Article
Incorporation mechanisms of Cl in peralkaline and peraluminous Na2O-CaO-Al2O3-SiO2 glasses as a model system for phonolitic melts were investigated using 35Cl, 23Na, 27Al, and 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The size and large distribution of electric field gradients for 35Cl causes loss of signal in t...
Article
The incorporation mechanisms of fluorine (F) into peralkaline and peraluminous Na2O–CaO aluminosilicate glasses with ∼65 mol% SiO2 (model system for phonolites) were investigated by magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. In 19F MAS NMR spectra of the fluorine-bearing peralkaline glasses at least five F sites could...
Article
Raman spectroscopy of carbonaceous material (RSCM) is frequently used to determine metamorphic peak temperatures from the structural order of carbonaceous material enclosed in metasediments. This method provides a quick, robust and relatively cheap geothermometer. However, the comparability of the RSCM parameter is low as there are at least three m...
Article
Raman spectroscopy of carbonaceous material (RSCM) is frequently used to determine metamorphic peak temperatures from the structural order of carbonaceous material enclosed in metasediments. This method provides a quick, robust and relatively cheap geothermometer. However, the comparability of the RSCM parameter is low as there are at least three m...
Article
The influence of 1.6 to 14.5 mol% water, 1.1 to 18.3 mol% fluorine (F) and 0.5 to 1.4 mol% chlorine (Cl) on the viscosity of peralkaline and peraluminous Na2O-CaO-Al2O3-SiO2 melts as a model system for phonolites was studied with the micropenetration method within the range of 10(9) to 10(13) Pa s. Water and F alone and combined decrease viscosity...
Article
Resistance to plastic deformation on surfaces of excavated glass fragments of late Byzantinic provenance and from early modern manufacturing was studied using Vickers indentation. Each glass surface consisted of a silica-rich alteration layer of consecutive multiple bands, as a result of a dissolution–reprecipitation mechanism of corrosion under lo...
Article
The structural variation of monoclinic C2/m alkali feldspars has been analysed, based on 50 previously-determined structures and 10 new structure refinements including three determinations of the structure of an Or90 orthoclase at temperatures of 600 K, 900 K and 1075 K. The influence of temperature, composition and state of Al, Si order on the ove...
Article
The rheology of three melt compositions containing different amounts of fluorine (F) and chlorine (Cl) or both was investigated with micropenetration and parallel-plate techniques. The heat capacity and configurational entropy of the melts were also determined. The observed viscosity range is between 105.5 and 1013 Pa s. The melts were produced in...
Article
The chemical diffusion of fluorine and chlorine in a Na-rich phonolitic melt of Montaña Blanca, Tenerife, was investigated experimentally at 1 kbar in the temperature range of 800 to 1200 °C, for anhydrous conditions and water contents of 2.1 to 2.4 wt.%. Diffusion couple experiments were performed in rapid quench cold-seal pressure vessels and in...
Article
We report an experimental study of total water diffusion (irrespective of water speciation) in two different phonolite melts, which are representative of Montaña Blanca, Tenerife, Spain (MBP) and Laacher See, East Eifel, Germany (LSP-II). Both phonolites have Na-rich compositions, but differ in their alumina saturation index, with MBP being peralka...
Article
Raman and mid-infrared (MIR) spectra have been measured on BaMn(CO3)(2), an ordered double carbonate, synthesised at low and at high pressures and temperatures (1 atm, 21 degrees C and 15 kbar, 510 +/- 10 degrees C, respectively). The results show no significant influence of synthesis conditions on the vibrational spectra of the double carbonate wi...
Article
Full-text available
The hydrothermal transformation of single aragonite crystals into polycrystalline calcite has been studied under hydrothermal conditions. The transformation involves a fluid-mediated replacement reaction, associated with fracturing of the initial aragonite crystal and growth of calcite throughout various parts of the reacted aragonite. The observed...
Article
The individual influences of F, B and P on viscosity of hydrous pegmatite forming melts have been determined experimentally. A starting glass composition (68.01 wt.% SiO2, 20.14 wt.% Al2O3, 7.73 wt.% Na2O and 4.26 wt.% K2O, Al/(Na+K)=1.16) was doped with different amounts of F (up to 4.81 wt.%), B2O3 (0.93 wt.%) and P2O5 (up to 2.98 wt.%). The visc...
Article
Raman spectroscopy of carbonaceous material (RSCM) is frequently used for geothermometric purposes. The Raman spectrum indicates the increase in structural order of the carbonaceous material by thermal overprint. The spectrum is usually processed by curve-fitting which gives peak-parameter ratios that express metamorphic temperature. The comparabil...
Article
An experimental study was performed to evaluate the effect of heat-up to various low temperatures on vitrinite reflectance (VR) at 2 kbar employing the same previously used heat-up procedures, starting material and apparatus. Heat-up is the isobaric experimental procedure consisting of the increase in temperature of the laboratory vitrinite maturat...
Article
Following a tentative evidence for the occurrence of low-temperature barium manganese(II) carbonates in brackish sediments of the Baltic Sea, a stoichiometric double carbonate, BaMn[CO3]2, was synthesized from aqueous solutions at ambient temperature for the first time. Here we report the results of a multi-method approach, including scanning elect...
Article
During the Miocene, the Brenner Normal Fault displaced the Austroalpine Steinach Nappe together with its underlying, tectonically thinned Austroalpine units from the tectonically underlying Penninic basement. The thermal effects of the displacement on the hanging wall were studied by geothermometry using Raman spectroscopy of carbonaceous material,...
Conference Paper
Kinetic processes during magma ascent may have a strong influence on the eruption style. In water bearing dacitic magmas decompression induced exsolution of water and accompanying crystallisation of plagioclase are the main processes which drive the system towards a new equilibrium state. We present new data on the evolution of residual glass compo...
Article
Xenon in the atmospheres of the Earth and Mars is characterized by a low abundance compared to other noble gases and by a depletion in light isotopes. By means of combined chemical analysis, in situ x-ray diffraction and Raman spectroscopy, we propose that Xe reacts with olivine at the high pressures and temperatures found in the upper mantle and i...
Article
Full-text available
Xenon in the atmospheres of the Earth and Mars is characterized by a low abundance compared to other noble gases and by a depletion in light isotopes. By means of combined chemical analysis, in situ X-ray diffraction and Raman spectroscopy, we propose that Xe reacts with olivine at the high pressures and temperatures found in the upper mantle and i...
Article
The experimental replacement of aragonite by calcite was studied under hydrothermal conditions at temperatures between 160 and 200 °C using single inorganic aragonite crystals as a starting material. The initial saturation state and the total [Ca²⁺]:[CO3²⁻] ratio of the experimental solutions was found to have a determining effect on the amount and...
Article
We report on temperature dependent crystal structures of sodium gallosilicate nitrite sodalite Na8[GaSiO4]6(NO2)2 between 293 and 973K. The crystal structures were refined from X-ray powder data Rietveld refinements in the space group P4¯3n. The gallium and silicon atoms on the tetrahedral framework positions are totally ordered. The nitrite anion...
Article
Full-text available
Oligoclase and labradorite crystals have been experimentally replaced by albite in an aqueous sodium silicate solution at 600°C and 2kbars. The replacement is pseudomorphic and is characterised by a sharp chemical interface which progresses through the feldspar while preserving the crystallographic orientation. Reaction rims of albite, up to 50μm t...
Article
The kinetics of CH(4)-C(2)H(6) replacement in gas hydrates has been studied by in situ neutron diffraction and Raman spectroscopy. Deuterated ethane structure type I (C(2)H(6) sI) hydrates were transformed in a closed volume into methane-ethane mixed structure type II (CH(4)-C(2)H(6) sII) hydrates at 5 MPa and various temperatures in the vicinity o...
Article
Regional scale albitisation of feldspars due to metasomatism is a relatively common phenomenon in the Earth's upper crust. The spatial relationship between large albitite bodies and ore mineral accumulations, which has often been recognized in nature, suggests that albitising fluids are conducive to remobilising elements and are capable of transpor...
Article
Single crystals of synthetic orthopyroxene were analyzed by Raman spectroscopy and electron microprobe in order to calibrate the effect of chemical composition on the position of Raman bands. For the Raman peak close to 670 cm(-1) we obtain the correlations between Raman shift (RS) and chemical composition FeO(wt%) = - 1.998 . RS(cm (1)) + 1373.2 a...
Article
The water solubility in various phonolite melts was determined experimentally at pressures between 50 and 395 MPa and at temperatures between 850 and 1200 °C. The aim of this study was to elucidate to which extent chemical and physical parameters such as relative amounts of alkali and alkaline earth elements or temperature affect the water solubili...
Article
Water speciation in hydrated Na2O·2SiO2 (NS2), Na2O·4SiO2 (NS4), and Na2O·6SiO2 (NS6) glasses was analyzed by near-infrared (NIR) spectroscopy and low temperature static 1H nuclear magnetic resonance (NMR) spectroscopy. For each composition 6–9 glasses containing between 0.5 and 7.0 wt.% total water (measured by Karl–Fischer titration) were used to...
Article
This study reports a calibration of Raman band positions for the determination of the Na/K ratio in disordered alkali feldspars. Crystals along the join sanidine–analbite were synthesised in steps of 10 mol% by ion exchange from a natural sanidine from Volkesfeld and were analysed by electron microprobe. Calibrations were made for the positions of...
Article
Equilibrium and disequilibrium degassing of a volatile phase from a magma of K-phonolitic composition was investigated to assess its behavior upon ascent. Decompression experiments were conducted in Ar-pressurized externally heated pressure vessels at superliquidus temperature (1050 °C), in the pressure range 10–200 MPa using pure water as fluid ph...
Article
Incorporation mechanisms of H_2 in silica glass were studied with Raman and infrared (IR) microspectroscopy. Hydrogenated samples were prepared at temperatures between 800 deg C and 955 deg C at 2 kbar total pressure. Hydrogen fugacities (f_{H_2}) were controlled using the double capsule technique with the iron-w\"ustite (IW) buffer assemblage gene...
Article
The speciation of H2O in float glass (FG) and soda lime silica glass (SLS) was investigated using IR and NMR spectroscopy. Molar absorption coefficients for the near-infrared (NIR) combination bands at 4500 and 5200 cm− 1, assigned to OH groups and H2O molecules, respectively, were determined using hydrated glasses containing 0.5–7.4 wt.% of dissol...
Chapter
This chapter reviews recent work on the determination of the structure of high pressure aluminosilicate glasses and presents new 17O and 27Al magic-angle spinning (MAS) and 17O triple-quantum (3Q) MAS NMR spectra that investigate the structure of K3AlSi3O9 (KAS) and Ca3Al2Si6018 (CAS) glasses quenched at 5 GPa. Comparison of the 27Al MAS spectra fo...
Article
The testing of rare gases to determine if they can be bound structurally in Earth materials is important given that they are widely used as chemically inert tracers for constraining the formation and evolution of the Earth. In the case of xenon, the search for a hidden reservoir in the Earth has been a long standing issue since it was noticed that...
Article
The reactivity of xenon with terrestrial oxides was investigated by in situ synchrotron x-ray diffraction. At high temperature (T > 500 kelvin), some silicon was reduced, and the pressure stability of quartz was expanded, attesting to the substitution of some xenon for silicon. When the quartz was quenched, xenon diffused out and only a few weight...
Article
To better understand the relationship between atomic-scale structures and densities of aluminosilicate glasses and liquids, we used Al-27 MAS NMR to determine the speciation of aluminum ions in K3AlSi3O9, Na3AlSi3O9, and Ca3Al2Si6O18 glasses quenched from melts at 3 to 10 GPa. These data are a first approximation of high-pressure melt structure and...
Article
This study uses Raman, 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) and 17O triple quantum (3Q) MAS NMR spectroscopies on K2Si4O9 glasses quenched from high pressure melts (5.7 and 8 GPa) and on high-pressure crystalline phases of K2Si4O9-wadeite and CaSi2O5 to investigate the structural mechanisms that create high coordinated sil...
Article
The investigation of hydrous boro(alumino)silicate melts and glasses with near infrared (NIR) spectroscopy revealed an important effect of boron on the water speciation. In the NIR spectra of B-bearing glasses new hydroxyl-related bands develop at the high frequency side of the 4500 cm-1 peak. In NaAlSi3O8 + B2O3 glasses this new peak is present as...
Article
Densities of aluminosilicate melts are strongly pressure-dependent, owing in part to atomic-scale structural changes. Glasses are commonly used as a first approximation for melts because the structure of a glass is that of the liquid at the glass transition temperature. This study used 27Al MAS NMR to determine the speciation of aluminum ions in gl...
Article
A novel method for the hydrothermal synthesis of (17)O-enriched alpha-Al(2)O(3) is presented. Its advantage compared to commonly used methods is that Al(2)O(3) is directly produced from metallic Al and (17)O-enriched H(2)O without formation of intermediate Al-hydroxide phases that require subsequent dehydration. This is a much more efficient use of...
Article
A combined nuclear magnetic resonance, infrared and Raman spectroscopic study on the effect of water dissolution on the structure of B-bearing aluminosilicate glasses is presented. The base composition was albite (NaAlSi3O8) to which different amounts of B2O3 (4.8, 9.1, 16.7 wt%) were added. Hydrous glasses containing 4.4 ± 0.1 wt% water were synth...
Article
Two of the most important structural controls on the properties of borosilicate glasses and glass melts are the variation between three- and four-coordination of network-forming boron cations, and the extent of mixing of Si and B. The effects of composition on these key parameters are relatively well studied. However, proposed mechanisms could be b...
Article
A kinetic model for the rate of iron–hydrogen redox exchange in silicate glasses and melts has been derived from time-series experiments performed on natural rhyolitic obsidians. Cylinders of the starting glasses were exposed to reducing mixtures composed of H2-Ar-CO2-CO in 1-atm furnaces and H2-Ar in a cold seal pressure vessel. Overall, runs cove...
Article
New 27Al NMR data are presented in order to clarify the discrepancies in the interpretation of the previous 27Al Magic Angle Spinning (MAS) spectra from hydrous aluminosilicate glasses. The 27Al MAS data have been collected at much higher magnetic field (14.1 and 17.6 T) than hitherto, and in addition, multiple quantum (MQ) MAS NMR data are present...
Article
An experimental study of H2O exsolution, bubble growth and microlite crystallisation during ascent (decompression) of silicic magmas in the volcanic conduit is presented. Isobaric and decompression experiments were performed on a rhyolitic melt at 860 C, NNO+1, H2O saturation, and pressures between 15 and 170 MPa. Two sets of decompression experime...
Article
Glass is commonly used as a structural analog for geologic melts because the structure of glass is that of the liquid at the fictive temperature (T_f). Typical fictive temperatures, however, can be > 1000^oC lower than the liquidus for high pressure systems. In this study, we used solid-state NMR (14.1T) to investigate the temperature dependence of...
Article
The solubilities of Ar and Xe in Fe-free synthetic haplogranitic and tholeiitic melts were experimentally determined in the pressure range of 1–11 GPa and at temperatures between 1500 and 2000°C. Experiments were performed in a piston cylinder apparatus (1–3 GPa) and in a multi-anvil apparatus (2–11 GPa). The noble gas concentrations in the quenche...
Article
To study the effects of total water content and alkali substitution on the structure of aluminosilicate glasses, two series of glasses belonging to the ternary system Quartz (Qz)-Albite (Ab)-Orthoclase (Or) were synthesized and investigated with nuclear magnetic resonance (NMR) spectroscopy. Series I consisted of seven glasses with normative compos...
Article
Water speciation in hydrous aluminosilicate glasses (with NaAlSi3O8, KAlSi3O8, LiAlSi3O8 and LiAlSi4O10 compositions) was studied with infrared (IR) and static ¹H nuclear magnetic resonance (NMR) spectroscopy. Using IR spectroscopy, the water speciation was determined from the peak intensities (linear absorbance as well as integrated intensity) of...
Article
Static 1H NMR spectra of hydrous NaAlSi3O8 glasses have been acquired at low temperature (140 K) in order to quantitatively determine OH and H2O concentrations. Since both components overlap in the spectra, an unambiguous determination of the line shapes is required. The structurally bonded hydroxyl groups are well described by a Gaussian line and...
Article
The compositional dependence of water incorporation mechanisms in melts and glasses belonging to the quartz (Qz)-albite (Ab) join was studied with nuclear magnetic resonance (NMR) spectroscopy. Dry and hydrous glasses (containing 3.8 +/- 0.1 wt% water) ranging in composition from Qz(90)Ab(10) to Qz(28)Ab(72) (in wt%) were synthesised and studied wi...
Article
The water solubility in haplogranitic melts (normative composition Ab39Or32Qz29) coexisting with H2O-H2 fluids at 800 and 950 °C and 1, 2 and 3 kbar vapour pressure has been determined using IR spectroscopy. The experiments were performed in internally heated pressure vessels and the hydrogen fugacity (f H2) was controlled using the double capsule...
Article
Solidus temperatures of quartz–alkali feldspar assemblages in the haplogranite system (Qz-Ab-Or) and subsystems in the presence of H2O-H2 fluids have been determined at 1, 2, 5 and 8 kbar vapour pressure to constrain the effects of redox conditions on phase relations in quartzofeldspathic assemblages. The hydrogen fugacity (f H2) in the fluid phase...
Article
An experimental setup is described to use the Shaw membrane technique in cold-seal pressure vessels (CSPV), allowing constant partial pressures of hydrogen (PH2) and hence hydrogen and oxygen fugacities (fH2, fO2) to be maintained in experimental charges for long durations (up to several weeks). The experimental setup permits the accurate determina...
Article
In the present study we combined complementary spectroscopic techniques such as NMR, Raman and infrared spectroscopy to investigate structural variations associated with B/Al substitution in a series of glasses along the join reedmergnerite-albite (NaBSi3O8- NaAlSi3O8. Since natural B-rich melts are commonly associated with hydrous granitic magmas...