TY - JOUR A1 - Leschik, M. A1 - Heide, G. A1 - Frischat, G.H. A1 - Behrens, H. A1 - Wiedenbeck, M. A1 - Wagner, N. A1 - Heide, K. A1 - Geißler, Heinz A1 - Reinholz, Uwe T1 - Determination of H2O and D2O contents in rhyolitic glasses N2 - Five distinct analytical techniques were compared for the quantification of the H2O (0·1-7·4 wt%) and D2O (up to 5·5 wt% D2O) contents in rhyolitic glasses. The hydrogen concentration in obsidians was measured using nuclear reaction analysis (NRA) and converted into H2O concentration. The bulk water content (H2O+D2O) of synthesised glasses was determined using thermal extraction in conjunction with Karl–Fischer titration (KFT). Unextracted H2O was measured by infrared (IR) spectroscopy after remelting the KFT products at high pressure. These well characterised glasses were subsequently used to calibrate secondary ion mass spectrometry (SIMS), infrared and evolved gas analysis (EGA). The calibrations of SIMS for H2O and D2O show a significant matrix effect at H2O and D2O concentrations larger than ~3 mol/l with the relative sensitivity factor (RSF) decreasing with bulk water content. Molar absorption coefficients for the OH stretching vibration band at 3570 cm-1 and the OD stretching vibration band at 2650 cm-1 in the infrared absorption spectra were reinvestigated. In the range 0·1-6 wt% the H2O content of glasses could be reproduced within analytical error using a constant linear molar absorption coefficient. However, it appears that the absorption coefficients for the 3570 cm-1 band as well as for the 2650 cm-1 band both decrease systematically with concentration of dissolved H2O and D2O (epsi3570=80 (±1) - 1·36(±0·23)CH2Ot and epsi2650=61·2(±1) - 2·52(± 0·30)CD2Ot). EGA allows quantification of the H2O content as well as the study of dehydration kinetics. It is shown that H2O is released under vacuum already at room temperature from glasses containing >7 wt% H2O. PY - 2004 UR - http://www.ingentaconnect.com/content/sgt/pcg/2004/00000045/00000004/art00003 SN - 0031-9090 VL - 45 IS - 4 SP - 238 EP - 251 PB - Thornton CY - Sheffield AN - OPUS4-6279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yang, Q.-C. A1 - Jochum, K.P. A1 - Stoll, B. A1 - Weis, U. A1 - Kuzmin, D. A1 - Wiedenbeck, M. A1 - Traub, Heike A1 - Andreae, M. O. T1 - BAM-S005 type A and B: new silicate reference glasses for microanalysis N2 - To test whether the silicate reference glasses BAM-S005-A and BAM-S005-B from BAM (The Federal Institute for Materials Research and Testing, Germany) are suitable materials for microanalysis, we investigated the homogeneity of these reference glasses using the microanalytical techniques EPMA, LA-ICP-MS and SIMS. Our study indicated that all major and most trace elements are homogeneously distributed at micrometre sampling scale in both types of glass. However, some trace elements (e.g., Cs, Cl, Cr, Mo and Ni) seem to be inhomogeneously distributed. We also determined the composition of BAM-S005-A and BAM-S005-B. The EPMA data of major elements confirmed the information values specified by the certificate. With the exception of Sr, Ba, Ce and Pb, our trace element data by LA-ICP-MS were also in agreement with the certified values within the stated uncertainty limits. The reasons for the discrepancy in these four elements are still unclear. In addition, we report new data for twenty-two further trace elements, for which the concentrations were not certified. Based on our investigation, we suggest that both of these materials are suitable for many microanalytical applications. KW - BAM-S005 KW - Microanalysis KW - Reference glasses KW - Homogeneity KW - Characterisation KW - Laser ablation ICP-MS KW - EPMA KW - SIMS KW - Glass KW - Reference material PY - 2012 DO - https://doi.org/10.1111/j.1751-908X.2012.00171.x SN - 1639-4488 SN - 1751-908X VL - 36 IS - 3 SP - 301 EP - 313 PB - Blackwell CY - Oxford AN - OPUS4-26563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spallanzani, Roberta A1 - Koga, K. A1 - Cichy, S. A1 - Wiedenbeck, M. A1 - Schmidt, B. A1 - Oelze, Marcus A1 - Wilke, M. T1 - Lithium and boron difusivity and isotopic fractionation in hydrated rhyolitic melts N2 - Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the difusivity 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 diferent Li and B contents; these were studied in difusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700–1250 °C for durations from 0 s to 24 h. From this we determined activation energies for Li and B difusion of 57±4 kJ/mol and 152±15 kJ/mol with pre-exponential factors of 1.53 × 10–7 m2/s and 3.80× 10–8 m2 /s, respectively. Lithium isotopic fractionation during difusion gave β values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li difusivities and isotopic fractionation results difer somewhat from earlier published values, but overall confrm that Li difusivity increases with water content. Our results on B difusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confrm that B difusivity is limited by viscous fow in silicate melts. Our results on Li and B difusion present a new tool for understanding degassing-related processes, ofering a potential geospeedometer to measure volcanic ascent rates. KW - Hydrated silicate melts KW - Stable isotopes KW - Diffusion KW - Isotopic fractionation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554496 DO - https://doi.org/10.1007/s00410-022-01937-2 VL - 177 IS - 8 SP - 1 EP - 17 PB - Springer AN - OPUS4-55449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tatzel, M. A1 - Frings, P. J. A1 - Oelze, Marcus A1 - Herwartz, D. A1 - Lünsdorf, K. A1 - Wiedenbeck, M. T1 - Chert oxygen isotope ratios are driven by Earth's thermal evolution N2 - The 18O/16O ratio of cherts (δ18Ochert) increases nearly monotonically by ~15‰ from the Archean to present. Two end-member explanations have emerged: cooling seawater temperature (TSW) and increasing seawater δ18O (δ18Osw). Yet despite decades of work, there is no consensus, leading some to view the δ18Ochert record as pervasively altered. Here, we demonstrate that cherts are a robust archive of diagenetic temperatures, despite metamorphism and exposure to meteoric fluids, and show that the timing and temperature of quartz precipitation and thus δ18Ochert are determined by the kinetics of silica diagenesis. A diagenetic model shows that δ18Ochert is influenced by heat flow through the sediment column. Heat flow has decreased over time as planetary heat is dissipated, and reasonable Archean-modern heat flow changes account for ~5‰ of the increase in δ18Ochert, obviating the need for extreme TSW or δ18Osw reconstructions. The seawater oxygen isotope budget is also influenced by solid Earth cooling, with a recent reconstruction placing Archean δ18OSW 5 to 10‰ lower than today. Together, this provides an internally consistent view of the δ18Ochert record as driven by solid Earth cooling over billion-year timescales that is compatible with Precambrian glaciations and biological. KW - Climate KW - Oxygen isotope ratios KW - Silica diagenesis KW - Early Earth KW - Heat flow PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569359 DO - https://doi.org/10.1073/pnas.2213076119 SN - 0027-8424 VL - 119 IS - 51 SP - 1 EP - 7 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-56935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosner, Martin A1 - Wiedenbeck, M. A1 - Ludwig, T. T1 - Composition-induced variations in SIMS instrumental mass fractionation during boron isotope ratio measurements of silicate glasses N2 - An analytical artefact is reported here related to differences in instrumental mass fractionation between NIST SRM glasses and natural geological glasses during SIMS boron isotope determinations. The data presented demonstrated an average 3.4‰ difference between the NIST glasses and natural basaltic to rhyolitic glasses mainly in terms of their sputtering-induced fractionation of boron isotopes. As no matrix effect was found among basaltic to rhyolitic glasses, instrumental mass fractionation of most natural glass samples can be corrected by using appropriate glass reference materials. In order to confirm the existence of the compositionally induced variations in boron SIMS instrumental mass bias, the observed offset in SIMS instrumental mass bias has been independently reproduced in two laboratories and the phenomenon has been found to be stable over a period of more than one year. This study highlights the need for a close match between the chemical composition of the reference material and the samples being investigated. Nous montrons l'existence d'un artefact analytique reliéà différents fractionnements de masse instrumentaux, observés sur les verres NIST SRM et des verres naturels durant des mesures des isotopes de bore par SIMS. Les données montrent une différence d'environ 3.4‰ entre les verres NIST et les verres naturels, de composition variant de basaltique à rhyolitique, en termes de fractionnement des isotopes du bore principalement induit par le phénomène de dispersion. Comme aucun effet de matrice n'a été observé entre les verres basaltiques et les verres rhyolitiques, le fractionnement de masse instrumental de la plupart des verres naturels peut être corrigé en utilisant des verres de références appropriés. Dans le but de confirmer l'existence de biais de masse liéà la composition lors de mesure du bore par SIMS, nous avons reproduit indépendamment le décalage observé entre deux laboratoires et ce phénomène s'est révélé stable sur une période de plus d'un an. Cette étude met en lumière le besoin d'ajuster précisément les compositions chimiques des matériaux de référence et des échantillons à analyser. KW - Boron isotopes KW - SIMS KW - Matrix effect KW - Glass reference materials KW - Instrumental mass fractionation KW - Isotope du bore KW - Effet de matrice KW - Matériaux vitreux de référence KW - Fractionnement de masse instrumental PY - 2008 DO - https://doi.org/10.1111/j.1751-908X.2008.00875.x SN - 1639-4488 SN - 1751-908X VL - 32 IS - 1 SP - 27 EP - 38 PB - Blackwell CY - Oxford AN - OPUS4-17783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosner, Martin A1 - Wiedenbeck, M. A1 - Ludwig, T. T1 - Determination of true boron isotope compositions of silicate glasses by SIMS: NIST SRM glasses and composition-induced variations in SIMS instrumental mass fractionation T2 - Jahrestagung Deutsche Mineralogische Gesellschaft 2008 CY - Berlin, Deutschland DA - 2008-09-14 KW - SIMS KW - Boron isotopes KW - Instrumental mass bias PY - 2008 SP - 1 CY - Berlin AN - OPUS4-20786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiedenbeck, M. A1 - Rosner, Martin A1 - Halama, R. A1 - Krienitz, M. T1 - Tourmaline reference materials for the in situ determination of lithium isotope composition T2 - 22. ICP-MS Anwendertreffen CY - Berlin, Germany DA - 2010-09-06 PY - 2010 AN - OPUS4-22572 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -