Continued Study of Presolar Graphite from Murchison Separate Kfa1
نویسندگان
چکیده
Introduction: Presolar graphite was isolated from the Murchison meteorite [1] only 3 years after the discovery of presolar SiC [2]. Yet it has not been studied as extensively as SiC. One of the reasons is that trace element concentrations in graphite grains are, in general, not high enough to perform isotopic analysis with sufficient precision. A new type of ion microprobe, the NanoSIMS, has recently been installed at Washington University in St. Louis. Its high sensitivity at highmass resolution and its multi-detection capability [3] make it possible to measure isotopic ratios of trace elements with unprecedented precision. We have previously reported C, N, O, and Si isotopic ratios of graphite from the Murchison KFA1 separate (2.052.10g/cm) [4]. We extended our studies to Mg-Al, K, Ca, and Ti in the same KFA1 graphite grains that we had previously analyzed in order to obtain correlated isotopic ratios.
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