ZIRCON U-Pb CHRONOLOGY OF THE AMPHIBOLITE OF TONGAN FORMATION AND ITS GEOLOGICAL SIGNIFICANCE
ZIRCON U-Pb CHRONOLOGY OF THE AMPHIBOLITE OF TONGAN FORMATION AND ITS GEOLOGICAL SIGNIFICANCE
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发表时间：
2014
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通讯作者：
Ren Guang-min
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作者：
Ren Guang-min
在会理地区前寒武纪地质调查过程中，在交平渡地区发现了以角闪岩为典型岩石的高绿片岩-角闪岩相岩石。鉴定和原岩恢复表明，角闪岩的原岩属于变质镁铁质火山岩。用LA-ICPMS方法测定了角闪岩中的锆石U-Pb同位素，获得了1720 Ma±7 Ma的协和年龄(MSWD=0.47，N=23)，代表了同安组下部的时代，表明镁铁质火山岩形成于古元古代晚期的大陆伸展环境。它反映了扬子地块西缘哥伦比亚超大陆的解体事件。
During the process of the Precambrian geological survey in Huili area,high greenschist-amphibolite facies rocks with the typical rock of amphibolite has been found in Jiaopingdu region.The identification and original rock recovery revealed that the original rock of amphibolite belong the metamorphosed mafic volcanic rocks.U-Pb isotope of zircons from amphibolite are determined by the LA-ICP-MS method,and yielded a concordia age of 1 720Ma±7Ma(MSWD=0.47,N=23).It represents the age of the lower part of Tongan Formation and implied that the mafic volcanic rocks formed in the continental extension environment at the late Paleoproterozoic of the ancient basement.Also,it reflects the breakup event of Columbia supercontinent in the western margin of the Yangtze Block.