岩石矿物学杂志2011，Vol.30Issue(1)：34-44,11.
南祁连东段化隆岩群形成时代的进一步限定
The further age constraint of Hualong Rock Group in the eastern segment of South Qilian Mountains
摘要
Abstract
The Hualong Rock Group of South Qilian orogenic basement remnants has aroused much interest among geologists for the occurrence of basic-ultrabasic rocks closely related to Cu-Ni (-PGE) ore deposits.With the acquisition of some precise Neoproterozoic zircon isotopic age data, the traditional understanding that Hualong Rock Group was formed in Archean-Paleoproterozoic has been challenged.High resolution LA-ICP-MS zircon U-Pb in situ dating of banded two mica-plagiogneiss (para-metamorphic rocks) from Hualong Rock Group in Riyue village of southern Huangyuan County yielded an age of 891 ± 7 Ma, which represents the lower age boundary of Hualong Rock Group.The age recently obtained from banded biotite-plagioclase amphibolite (whose protolith was intermediate volcanic rocks) is 884 ± 9 Ma.Based on isotopic dating combined with the results obtained by previous researchers, the authors further restricted the age of Hualong rock Group to Early Neoproterozoic, i.e., Qingbaikou period.It is believed that the volcano-sedimentary rocks of Hualong Rock Group serve as geological records of the breakup of the Rodinia supercontinent.Recently, zircon U-Pb dating yielded an age of 724.4 ± 3.7 Ma from gneissic plagioclase amphibolite (whose protolith was gabbro)near the Dadaoerji Cu-Ni ore deposit in the western part of the Qilian orogenic belt, whereas a U-Pb age of 724.4 ± 3.7 Ma was yielded from zircon and baddeleyite in Jinchuan ultrabasic rock of Longshou Mountain area in northern Qilian orogenic belt; these data can also be regarded as geological records of the breakup of the Rodinia supercontinent.These results indicate that the importance of Rodinia supercontinent breakup event and its related mineralization in Precambrian period of the Qilian orogenic belt and its adjacent areas should not be underestimated.关键词
LA-ICP-MS/锆石U-Pb年代学/化隆岩群/南祁连造山带/新元古代分类
天文与地球科学引用本文复制引用
何世平,李荣社,王超,于浦生,张宏飞,辜平阳,时超..南祁连东段化隆岩群形成时代的进一步限定[J].岩石矿物学杂志,2011,30(1):34-44,11.基金项目
国土资源大调查项目(1212010610102) （1212010610102）
