摘要
金红石是榴辉岩中的主要含钛副矿物。中国大陆科学钻探工程(CCSD)主孔100～2000m岩心样品中,金红石榴辉岩、多硅白云母榴辉岩和蓝晶石榴辉岩中都程度不等地含有金红石。金红石既可以与其他矿物一起被石榴石、绿辉石等主要变质矿物包裹,也可以包裹其他矿物。本文利用电子探针技术,对CCSD所揭示的超高压榴辉岩的金红石中的矿物包裹体进行了鉴定和分析。结果显示,绿辉石、富铪锆石、高铝榍石、韭闪石和红闪石、斜黝帘石等矿物包裹体形成于榴辉岩相进变质至峰期变质阶段;随着超高压变质带快速折返,榴辉岩经受强烈的退变质作用,包括金红石、绿辉石在内的多种矿物都经受了退变质作用,与金红石共生的钛铁矿完全或者部分退变成含铁金红石和钛铁晶石。在退变的金红石中,还发现了透辉石+斜长石后成合晶、低铝榍石、镁绿闪石等退变质矿物组合。
Rutile is a common Ti-bearing accessory mineral in eclogites. In the 100--2 000 m borehole samples of the Chinese Continental Scientific Drilling Project, rutile appears in different amounts in rutile eclogite, phengite eclogite and kyanite eclogite. It, together with other minerals, can be wrapped in major metamorphic minerals such as garnets and omphacites, or can wrap other minerals. Inclusions in rutiles from CCSD UHP eclogites were studied by electron microprobe. The result shows that the inclusions such as omphacites, Hf-rich zircons, high-Al sphenes, pargasites, katophorites and clinozoisites were formed during the progradation of eclogite-facies to peak metamorphism. With the exhumation of the Sulu UHP metamorphic belt, the eclogites underwent extensive retrograde metamorphism, and lots of minerals such as rutiles and omphacites experienced retrograde metamorphism too. Ilmenites coexisting with rutiles were subjected to different extents of retrometamorphism, yielding Fe-rutile and ulvospinel. Therefore, some retrograde mineral assemblages such as symplectites of diopside ＋ plagioclase, low-Al sphene, magnesiotaramite were found in retrograded rutile.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2006年第1期61-70,共10页
Acta Petrologica et Mineralogica
基金
国家重点基础研究发展规划项目(2003CB716507)
国家自然科学基金优秀创新群体项目(40221301)
南京大学地质学研究生创新研究资助项目
