Light element geochemistry of the Apollo 12 site |
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| Authors: | JF Kerridge IR Kaplan CC Kung DA Winter DL Friedman DJ DesMarais |
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| Institution: | Institute of Geophysics, University of California, Los Angeles, CA 90024, U.S.A.;Extraterrestrial Biology Division, NASA Ames Research Center, Moffett Field, CA 94035, U.S.A. |
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| Abstract: | Analytical techniques of improved sensitivity have revealed details of the concentrations and isotopic compositions of light elements for a comprehensive suite of samples from the Apollo 12 regolith. These samples show a wide spread in maturity, although maximum contents observed for solar wind elements are less than observed at other sites, possibly reflecting relative recency of craters at the Apollo 12 site. Isotopic composition of nitrogen is consistent with the idea that 15N/14N in the solar wind has increased with time, at least a major part of this increase having occurred in the past 3.1 Gyr. Sulfur isotope systematics support a model in which sulfur is both added to the regolith, by meteoritic influx and lost, by an isotopically selective process. Most soils from this site are heavily contaminated with terrestrial carbon. |
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