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新发现于赣东北弋阳县南的麻粒岩是一个基性麻粒岩,具有石榴子石+斜长石+紫苏辉石+黑云母+磁铁矿的矿物组合,根据矿物成分变化和矿物的包含关系确定了峰前变质(M1)和峰期变质(M2).成岩格子和地质温压计计算限定了麻粒岩峰前变质的温压是830~870℃和~1.0 GPa,而峰期的变质条件是850~900℃和0.7~0.8 GPa,显示了一个近于等温降压的顺时针P-T-t轨迹.LA-ICPMS锆石U-Pb定年表明麻粒岩相变质作用发生在436 Ma,而其原岩可能形成于新元古代早期.结合已有的发现,本文指出华夏地块内发生的早古生代(加里东期)高级变质作用与碰撞造山带作用有关,很可能是扬子地块与东冈瓦纳大陆挤压碰撞的结果.
The granulite newly discovered in south Yiyang County, northeastern Jiangxi is a basic granulite with mineral assemblages of garnet + plagioclase + peridotite + biotite + magnetite. According to the change of mineral composition and The mineral inclusions determine the pre-peak metamorphism (M1) and the peak metamorphism (M2). The diagenetic grids and geothermometers calculate the tem- peratures that delineate the pre-peak metamorphic peaks of granulite at 830-870 ° C and ~ 1.0 GPa, The peak metamorphic conditions are 850-900 ℃ and 0.7-0.8 GPa, showing a clockwise Ptt trajectory near the isothermal buck. The LA-ICPMS zircon U-Pb dating indicates that granulite facies metamorphism occurred at 436 Ma , And its original rocks may form in the early Neoproterozoic. Combined with the existing findings, this paper points out that the Early Paleozoic (Caledonian) metamorphism in the Huaxia block is related to the collision orogenic belt and is likely to be related to the Yangtze block The result of crushing collisions with the eastern Gondwana mainland.