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安徽岳西县石关混合岩属于原北大别变质杂岩的一部分。锆石SHRIMPU-Pb定年结果:第一次变质时间为232Ma,相当于晚三叠世早期,第二次变质时间为207Ma,相当于晚三叠世晚期。复合锆石的核部(继承锆石)为发育韵律环带的岩浆碎屑锆石,其年龄值分别为560Ma、444Ma、394Ma、378Ma和331Ma,暗示其原岩非岩浆岩,而应为沉积岩;研究结果还表明,北大别石关混合岩经历了两次变质作用:①超高压变质作用,变质时间为232Ma(n=5加权平均年龄);②退变质作用,时间为207Ma。与苏鲁地区超高压变质和退变质时间一致。
Rocky Mountain, Yuexi County, Anhui Province, is a part of the original Dabie metamorphic complex. The zircon SHRIMPU-Pb dating results show that the first metamorphism is 232Ma, which is equivalent to the early Late Triassic, the second metamorphism is 207Ma, which is equivalent to late Late Triassic. The zircons of the composite zircons (inherited from zircon) are magmatic detrital zircons with prosodic zonation, and their age values are 560Ma, 444Ma, 394Ma, 378Ma and 331Ma, respectively, indicating that the protoliths are non-magmatic but rather sedimentary The results also show that the metamorphic rocks have experienced two metamorphism: ① UHPM metamorphism, metamorphism time 232Ma (n = 5 weighted average age); ② degenerate effect, the time was 207Ma. It is consistent with UHPM metamorphism and retrogressive metamorphism in the Sulu region.