期刊
AMERICAN MINERALOGIST
卷 92, 期 10, 页码 1772-1775出版社
MINERALOGICAL SOC AMER
DOI: 10.2138/am.2007.2697
关键词
ion microprobe; SIMS; zircon; diffusion; oxygen isotopes; stable isotopes; granulites facies; migmatites
Ion microprobe analysis with a sub-micrometer diameter spot reveals a sharp, 2 mu m gradient in oxygen isotope ratio proving that oxygen diffusion in zircon is slow even under prolonged high-grade metamorphism. The data are consistent with an oxygen diffusion coefficient of 10(-23.5+/-1) cm(2)/s. Furthermore, this gradient is found in a zircon that contains clear textural evidence of recrystallization in nearby regions. This finding shows that through careful textural and chemical analysis, primary information can be extracted from a zircon that has also undergone partial recrystallization. The oxygen isotope ratios found in zircon have been used to infer magmatic and pre-magmatic histories, including the presence of liquid water on the surface of earliest Earth. Recently, these interpretations have been questioned with the assertion that zircon may not retain its primary oxygen isotope signature through metamorphism. The slow diffusion confirmed by these results supports interpretations that assume preservation of magmatic compositions.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据