柴北缘欧龙布鲁克地块中元古代晚期麻粒岩相变质作用——来自石榴夕线堇青石片麻岩的岩石学、相平衡模拟和U-Pb年代学的制约

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中文摘要：在欧龙布鲁克地块乌兰北部地区察汗河岩群中识别出麻粒岩相石榴夕线堇青石片麻岩,其矿物组合为石榴子石、夕线石、堇青石、黑云母、斜长石、钛铁矿和少量钾长石等.岩相学观察显示,M1阶段矿物组合有斜长石±钾长石+石榴子石+夕线石+石英,M2阶段矿物组合有斜长石±钾长石+石榴子石+夕线石+石英+钛铁矿+黑云母,M3阶段矿物组合有堇青石+黑云母+钛铁矿+石英+石榴子石+斜长石±钾长石.相平衡模拟计算结果显示,该岩石的峰期温压条件为p=0.92～1.08 GPa,峰期温度t＞790℃,峰期之后经历升温降压的p-T演化轨迹.锆石和独居石LA-ICP-MS U-Pb年代学研究获得的变质年龄分别为1 133±14 Ma和1 125±37 Ma,1 133～1 125 Ma应代表了该期麻粒岩相变质作用的时代.结合区域地质资料和已有的研究成果,我们认为乌兰北部察汗河岩群的石榴夕线堇青石片麻岩可能形成于大洋俯冲作用下的弧或弧后构造环境,乌兰北部的岩浆-变质杂岩带经历了从中元古代晚期-新元古代早期俯冲增生到碰撞造山的演化过程,是全球Rodinia超大陆汇聚过程的响应.

外文标题：Late Mesoproterozoic granulite-facies metamorphism in the Oulongbuluke block of the North Qaidam Mountains:Constraints from petrology,phase equilibrium modeling and U-Pb dating of garnet-sillimanite-cordierite gneisses

外文摘要：The garnet-sillimanite-cordierite gneiss,which has been identified from the Chahanhe Group in the northern region of the Oulongbuluke block,consists of garnet,sillimanite,cordierite,biotite,plagioclase,ilmenite,and a small amount of K-feldspar.Petrographic observation shows that three stages(M1,M2 and M3)of mineral assem-blage can be recognized.They are M1:Pl±Kfs+Grt+Sill+Qz,M2:Pl±Kfs+Grt+Sill+Qz+Ilm+Bt,and M3:Crd+Bt+Ilm+Qz+Grt+Pl±Kfs.Phase equilibrium modelling shows that the peak p-T conditions of the garnet-sillimanite-cordierite rock are p=0.92～1.08 GPa and t＞790℃,and experienced a heating decompression during exhuma-tion.The metamorphic ages acquired from zircon and monazite U-Pb dating by LA-ICP-MS are 1 133±14 Ma and 1 125±37 Ma,respectively,which represent the timing of granulite-facies metamorphism.Combining regional ge-ology with our data,we suggested that the garnet-sillimanite-cordierite rock in the Chahanhe Group formed in an arc or back-arc system related to oceanic subduction.The magmatic-metamorphic complex belt in the northern region of the Oulongbuluke block underwent an evolutionary process from subduction-accretion to collision orogeny during late Mesoproterozoic to early Neoproterzoic,which is a response to the convergence process of Rodinia supercontinent.

外文关键词：

Oulongbuluke blockgarnet-sillimanite-cordierite gneissgranulite-faciesRodinia supercontinentphase equilibrium modelling

作者：

毛小红、路增龙、张建新、郭祺、武亚威

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作者单位：

中国地质科学院地质研究所自然资源部深地动力学重点实验室,北京 100037

中色紫金地质勘查(北京)有限责任公司,北京 100012

北京大学地球与空间科学学院,北京 100871

关键词：

欧龙布鲁克地块石榴夕线堇青石片麻岩麻粒岩相 Rodinia超大陆相平衡模拟

基金：

国家自然科学基金项目国家自然科学基金项目中国地质科学院基本科研业务费项目中国地质科学院地质研究所基本科研业务费项目

项目编号：

4210224642202058JKYZD202310J2319

出版年：

2024

DOI：

10.20086/j.cnki.yskw.2024.0202

岩石矿物学杂志

中国地质学会岩石学专业委员会矿物学专业委员会中国地质科学院地质所

岩石矿物学杂志

CSTPCD北大核心

影响因子：1.104

ISSN：1000-6524

年,卷(期)：2024.43(2)