大别地区榴辉岩中几种超高压变质矿物研究

根据镜下观察,在大别地区东南部榴辉岩中陆续发现柯石英、金刚石和文石等三种超高压变质矿物,拉曼分子探针检测进一步证实了这些发现。柯石英和文石均被包裹于石榴石或绿辉石晶体之内,而基质中则分别以低压多型变体石英和方解石的形式存在,说明其保存除快速构造抬升的外部条件外,还与寄主矿物机械阻力及晶内低压缩性有关。作为榴辉岩相的早期共生矿物,它们的出现证明该区榴辉岩经历了超高压变质作用。

STUDY OF SEVERAL ULTRAHIGH PRESSURE METAMORPHIC MINERAL IN ECLOGITES IN THE DABIE DISTRICT

The ultrahigh pressure metamorphic coesite,diamond and aragonite are discovered one after the other in eclogites in the south-east of the Dabie district based on the observation under microscope and confirmed by Raman molecular microprobe analysis. Coesite and aragonite were all included in garnet or omphacite and existed as low-pressure quartz and calcite polymorphs respectively in the matrix. Beside the rapid tectonic uplift of eclogites, the preservation of ultrahigh pressure metamorphic mineral is mainly related with the low compressibility and the mechanical strength of the host mineral. As the early coexisting mineral of eclogite facies,the occurrence of these mineral indicates that the eclogites in this district underwent ultrahigh pressure metamorphism.