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本文报道大别山安徽省岳西县碧溪岭深色榴辉岩和片麻状花岗质岩石的锆石SHRIMP分析结果。深色榴辉岩的原岩为基性凝灰岩,锆石在岩石中主要产于石英、石榴子石和绿辉石内,为高压一超高压变质作用的产物,内部主体形成年龄约为757±7Ma,代表高压—超高压榴辉岩相变质事件的时代;经受了后期流体改造的锆石边部年龄为223±3Ma。在片麻状花岗质岩石中,发育韵律环带结构的深熔锆石形成于约727±15Ma,受后期流体改造的锆石边部年龄为219±3Ma。综合野外地质关系、区域地质背景和锆石的岩相学特征,笔者提出了碧溪岭榴辉岩相岩石高压—超高压变质作用发生于晋宁期,印支期仅代表一次后期流体改造事件的观点。
This paper reports the zircon SHRIMP results of the Bixi Ridge eclogites and gneissic granites in Yuexi County, Anhui Province. The original rock of the dark eclogite is basic tuff. The zircon is mainly produced in quartz, garnet and omphacite in the rock, which is the product of high pressure-ultrahigh pressure metamorphism. The inner body is formed with an age of about 757 ± 7Ma , Representing the era of high-pressure-ultrahigh-pressure eclogite facies metamorphism events. The zircon ages at the late stage of fluid transformation were 223 ± 3Ma. In the gneissic granitic rocks, the zircons with developed rhythmic ring structure are formed at about 727 ± 15Ma, and the marginal zircons modified by later fluids are 219 ± 3Ma. Based on the field geological relationship, the regional geological background and the petrographic features of zircon, the author proposed that the high-pressure-ultrahigh-pressure metamorphism of the Eclogite facies of Bixiling took place in the Jinning Period, and the Indosinian Period represents only a later fluid transformation event the opinion of.