Trace element concentrations in silicate spherules from oceanic sediments |
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Authors: | Hiroshi Nagasawa Kazuo Yamakoshi Tadashi Shimamura |
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Affiliation: | Department of Chemistry, Gakushuin University, Mejiro, Toshima-ku, Tokyo, Japan;Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo, Japan |
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Abstract: | The possible existence of meteoritic spherules was investigated among several silicate spherules separated from oceanic sediments and analyzed by means of INAA (instrumental neutron activation analysis).A 0.72 mg glassy spherule was found to have uniform enrichment of 4 ~ 5 for the refractory REE (rare earth elements) and Sc with substantial depletion of Ce relative to chondritic abundances. This implies that this spherule is meteoritic in origin and that the enrichment of refractory elements was established by high temperature heating in a high O/H environment, possibly at the time of entering the Earth's atmosphere.The other three analyzed spherules showed major and trace element abundances that are consistent with an origin in the oceanic environment. |
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