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对大别造山带超高压榴辉岩中不同类型的变质脉开展了变质锆石学和微区地球化学对比研究,包括矿物多相包裹体观察,微量元素和氢氧同位素分析,锆石内部结构和外部形态,U-Pb定年,微量元素,Lu-Hf和O同位素分析.结果发现,形成石英脉的流体是高压富水的,引起变质新生锆石的生长,同时伴随原岩残留岩浆锆石的固态重结晶和溶解重结晶;形成复杂矿物组合脉的流体可能具有超临界性质,引起原岩残留锆石的溶解,Zr的短距离迁移以及变质新生锆石再沉淀.两种不同类型的变质脉中残留岩浆锆石和变质新生锆石的同时存在,指示在俯冲带变质流体活动过程中,同时发生原岩残留岩浆锆石的物理搬运和元素Zr的化学迁移.
The metamorphic zircons and micro-geochemical correlation studies on different types of metamorphic veins in ultrahigh-pressure eclogites of the Dabie orogenic belt have been carried out, including the observation of multi-phase inclusions in minerals, the analysis of trace elements and hydrogen and oxygen isotopes, the internal structure of zircon And U-Pb dating, trace elements, Lu-Hf and O isotope analysis results show that the formation of quartz vein fluid is high pressure water-rich, causing the growth of metamorphic nascent zircon, accompanied by the original rock residual magmatic zircon Solid-state recrystallization and dissolution recrystallization; the fluids forming complex mineral assemblages may have supercritical properties that cause the dissolution of residual zircon from the original rocks, the short-range migration of Zr, and the reformation of newborn zircons. Two different types of metamorphism The presence of residual magmatic zircons and metamorphic nascent zircons in the vein indicates that both the physical transport of the residual magmatic zircons from the original rocks and the chemical migration of elemental zirconium occur simultaneously during the activity of the metamorphic fluids in the subduction zone.