Rhenium-Osmium Isotope Systematics of Tektites and Impact Glasses

玻璃陨石是陆地岩石在超高速撞击地球过程中熔融和淬灭的产物。用于Re-Os同位素分析的高灵敏度负热电离技术(NTIMS)的出现使该系统非常适合于理解玻璃陨石中经常升高的亲铁元素含量的问题。P.I.提议由NTIMS对来自澳大拉西亚和象牙海岸散布的油田的玻璃陨石以及Auoellul玻璃进行Re-Os同位素研究。有了Re-Os同位素系统，就有了独特的机会来确定在玻璃陨石中发现的Os是否真的是地外、地壳或两者的混合体。这是必要的，以表明玻璃陨石中的亲铁元素特征是陨石污染的结果还是目标岩石的原位还原的结果。

Tektites are the product of melting and quenching of terrestrial rocks during hypervelocity impacts on the Earth. The advent of the highly-sensitive negative thermal ionization technique (NTIMS) for Re-Os isotopic analysis makes this system ideally suited to the problem of understanding the often elevated siderophile element content of tektites. The P.I.s propose to carry out Re-Os isotopic studies by NTIMS on tektites from the Australasian and Ivory Coast Strewn fields and on the Auoelloul glasses. With the Re-Os isotopic system there is the unique opportunity to determine if the Os found in tektites is really extraterrestrial, crustal or a mixture of both. This is necessary for showing whether the siderophile element signatures in tektites are a result of meteorite contamination or in-situ reduction of the target rocks.