Details zur Publikation |
Kategorie | Textpublikation |
Referenztyp | Zeitschriften |
DOI | 10.1016/j.chemgeo.2017.07.027 |
Titel (primär) | New biotite and muscovite isotopic reference materials, USGS57 and USGS58, for δ2H measurements–A replacement for NBS 30 |
Autor | Qi, H.; Coplen, T.B.; Gehre, M.; Vennemann, T.W.; Brand, W.A.; Geilmann, H.; Olack, G.; Bindeman, I.N.; Palandri, J.; Huang, L.; Longstaffe, F.J. |
Quelle | Chemical Geology |
Erscheinungsjahr | 2017 |
Department | ISOBIO |
Band/Volume | 467 |
Seite von | 89 |
Seite bis | 99 |
Sprache | englisch |
Keywords | HTC; Hydrogen isotopes; Isotope standards; Hydrous minerals |
UFZ Querschnittsthemen | RU3; |
Abstract | The advent of continuous-flow isotope-ratio mass
spectrometry (CF-IRMS) coupled with a high temperature conversion (HTC)
system enabled faster, more cost effective, and more precise δ2H
analysis of hydrogen-bearing solids. Accurate hydrogen isotopic
analysis by on-line or off-line techniques requires appropriate isotopic
reference materials (RMs). A strategy of two-point calibrations
spanning δ2H range of the unknowns using two RMs is
recommended. Unfortunately, the supply of the previously widely used
isotopic RM, NBS 30 biotite, is exhausted. In addition, recent
measurements have shown that the determination of δ2H
values of NBS 30 biotite on the VSMOW-SLAP isotope-delta scale by
on-line HTC systems with CF-IRMS may be unreliable because hydrogen in
this biotite may not be converted quantitatively to molecular hydrogen.
The δ2HVSMOW-SLAP values of NBS 30 biotite analyzed by on-line HTC systems can be as much as 21 mUr (or ‰) too positive compared to the accepted value of − 65.7 mUr,
determined by only a few conventional off-line measurements. To ensure
accurate and traceable on-line hydrogen isotope-ratio determinations in
mineral samples, we here propose two isotopically homogeneous, hydrous
mineral RMs with well-characterized isotope-ratio values, which are
urgently needed. The U.S. Geological Survey (USGS) has prepared two such
RMs, USGS57 biotite and USGS58 muscovite. The δ2H
values were determined by both glassy carbon-based on-line conversion
and chromium-based on-line conversion, and results were confirmed by
off-line conversion. The quantitative conversion of hydrogen from the
two RMs using the on-line HTC method was carefully evaluated in this
study. The isotopic compositions of these new RMs with 1-σ uncertainties
and mass fractions of hydrogen are: USGS57 (biotite) δ2HVSMOW-SLAP = − 91.5 ± 2.4 mUr (n = 24) Mass fraction hydrogen = 0.416 ± 0.002% (n = 4) Mass fraction water = 3.74 ± 0.02% (n = 4) USGS58 (muscovite) δ2HVSMOW-SLAP = − 28.4 ± 1.6 mUr (n = 24) Mass fraction hydrogen = 0.448 ± 0.002% (n = 4) Mass fraction water = 4.03 ± 0.02% (n = 4). These δ2HVSMOW-SLAP values encompass typical ranges for solid unknowns of crustal and mantle origin and are available to users for recommended two-point calibration. |
dauerhafte UFZ-Verlinkung | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=19174 |
Qi, H., Coplen, T.B., Gehre, M., Vennemann, T.W., Brand, W.A., Geilmann, H., Olack, G., Bindeman, I.N., Palandri, J., Huang, L., Longstaffe, F.J. (2017): New biotite and muscovite isotopic reference materials, USGS57 and USGS58, for δ2H measurements–A replacement for NBS 30 Chem. Geol. 467 , 89 - 99 10.1016/j.chemgeo.2017.07.027 |