delta Si-30 and delta Si-29 determinations on USGS BHVO-1 and BHVO-2 reference materials with a new configuration on a Nu Plasma multi-collector ICP-MS
We report silicon isotopic determinations for USGS rock reference materials BHVO-1 and BHVO-2 using a Nu Plasma multi-collector (MC)-ICP-MS, upgraded with a new adjustable entrance slit, to obtain medium resolution, as well as a stronger primary pump and newly designed sampler and skimmer cones ("B" cones). These settings, combined with the use of collector slits, allowed a resolution to be reached that was sufficient to overcome the (NO)-N-14-O-16 and N-14(2) interferences overlying the Si-30 and the Si-28 peaks, respectively, in an earlier set-up. This enabled accurate measurement of both delta Si-30 and delta Si-29. The delta value is expressed in per mil variation relative to the NBS 28 quartz reference material. Based on data acquired from numerous sessions spread over a period of six months, we propose a recommended average delta Si-30 of -0.33 +/- 0.05 parts per thousand and -0.29 +/- 0.11 parts per thousand (2se) for BHVO-1 and BHVO-2, respectively. Our BHVO grand mean silicon isotope composition (delta Si-30 = -0.31 +/- 0.06 parts per thousand) is significantly more negative than the only published value for BHVO-2, but is in very good agreement with the recently established average value of ocean island basalts (OIB), confirming the conclusion that the OIB reservoir has a distinct isotopic composition from the solar reservoir as sampled by chondrites.
Abraham, K., Opfergelt, S., Fripiat, F., Cavagna, A.-J., de Jong, J. T. M., Foley, S. F., André, L., & Cardinal, D. (2008). delta Si-30 and delta Si-29 determinations on USGS BHVO-1 and BHVO-2 reference materials with a new configuration on a Nu Plasma multi-collector ICP-MS. Geostandards and Geoanalytical Research, 32(2), 193-202. https://doi.org/10.1111/j.1751-908X.2008.00879.x (Original work published 2008)