USGS GSD-1G: A Geological Reference Glass for in situ Elemental and Isotopic Analysis
Abstract
To overcome the drawback of synthetic calibration materials for microanalysis of geological samples, the USGS prepared basaltic GS reference glasses, which are doped with many trace elements in similar abundances. The GSD-1G glass is of special interest, because the trace elements have appropriate concentrations of about 50 μg/g. Meanwhile first analytical results have been published which all agree very well. The GeoReM preferred values (http://georem.mpch-mainz.gwdg.de) have therefore a high level of confidence. For in situ isotope analysis an increasing need exists for well characterized reference glasses to satisfy the requirements for new LA-ICP-MS and SIMS applications. We have therefore determined the isotopic composition of Li, B, Si, Ca, Sr, Nd and Pb in GSD-1G by high-precision bulk and microanalytical techniques (Table 1). To check isotopic homogeneity, three different glass splits were analyzed. The highly precise δ11B, δ44/40Ca, 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb values are indistinguishable within uncertainty limits indicating isotopic homogeneity. Small Pb isotopic heterogeneities between splits are detected in the TIMS triple spike data but not resolved in the LA-ICP-MS Pb data due to the larger uncertainty, a factor of 10 greater than that of TIMS. Nevertheless, the mean LA-ICP-MS 207Pb/206Pb and 208Pb/206Pb agree well with the TIMS data. δ29Si and δ30Si were determined by LA-MC-ICP-MS using a femtosecond laser. The δ7Li and Li concentration (43.8 μg/g) values obtained by MC-ICP-MS also agree well with previously published MC-ICP-MS, TIMS and SIMS Li isotopic data analyzed on different splits (30.3‰ Jochum et al. (2006); 31.14, 31.7, 31.3‰ Kasemann et al. (2005)) and the GeoReM preferred Li concentration (43 μg/g) indicating isotopic and elemental homogeneity of Li in GSD-1G. Table 1: Compilation of isotope data of USGS GSD-1G reference glass. δ7Li(‰ LSVEC): 30.4 using MC-ICP-MS δ11B(‰ NIST951: 10.07; 9.80; 10.74 using TIMS δ29Si(‰ NIST8546): -0.080 using LA-MC-ICP-MS δ30Si(‰ NIST8546): -0.224 using LA-MC-ICP-MS δ44/40Ca(‰ NIST915a): 0.79; 0.90; 0.89 using TIMS 87Sr/86Sr: 0.709396; 0.709403; 0.709403 using TIMS 143Nd/144Nd: 0.511513; 0.511514; 0.511515 using TIMS 206Pb/204Pb: 19.578; 19.579; 19.578 using TIMS-triple spike 207Pb/204Pb: 15.7436; 15.7446; 15.7459 using TIMS-triple spike 208Pb/204Pb: 38.906; 38.910; 38.916 using TIMS-triple spike 207Pb/206Pb: 0.80416; 0.80515; 0.80424 using TIMS-triple spike 208Pb/206Pb: 1.9872; 1.9873; 1.9876 using TIMS-triple spike 207Pb/206Pb: 0.8042 using LA-ICP-MS 208Pb/206Pb: 1.987 using LA-ICP-MS
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.V13A2095J
- Keywords:
-
- 1040 Radiogenic isotope geochemistry;
- 1041 Stable isotope geochemistry (0454;
- 4870);
- 1065 Major and trace element geochemistry;
- 1094 Instruments and techniques