摘要
团麻断裂以西的河南大别山区榴辉岩及其围岩蓝晶石石英岩中首次发现柯石英。含柯石英榴辉岩的矿物共生组合为石榴石+绿辉石+蓝晶石+多硅白云母+石英(柯石英)+金红石,其形成温压条件为T=610～740℃,P≥2.8 GPa。含柯石英榴辉岩及其围岩同时经历了超高压变质作用,可能由扬子板块向华北板块深俯冲作用形成,俯冲深度可迭90km以上。河南大别山区含柯石英榴辉岩的发现扩大了中国中东部含柯石英榴辉岩带的分布区。
Coesite has been first discovered in the eclogites and their country rocks -kyanite quartzite in the western area of Tuanma Fault from the Dabie Mountains , Henan province. The mineral assemblage in the eclogites is garnet + omphacite + kyanite+ phengite+quartz (coesite)+rutile. The coesite - bearing eclogites were estimated to be formed at T=610-740℃ , P≥2. 8 GPa. The coesite-bearing eclogites and their country rocks underwent simultaneously ultra - high - pressure metamorphism. They might be produced by subduction to depths of more than 90km during continent - continent collision between Yangtze and the North China cratons. The discovery of coesite -bearing eclogites in this area enlarges the region of coesite-bearing eclogite belt in Central -Eastern China.
关键词
榴辉岩
蓝晶石
石英岩
柯石英
河南
eclogitc, kyanite quartzite, coesite, ultra - high - pressure metamorphism, Henan province
