蒙古国杭爱山地区泥盆纪-石炭纪岩浆作用:来自碎屑锆石U-Pb年代学和Hf同位素的制约  

Devonian to Carboniferous Magmatism in the Hangay Mountains of Central Mongolia:Constraints of Detrital Zircon U-Pb Geochronology and Hf Isotopes

作　　者：令佳琪 李鹏飞 李震[1,2,3] LING Jiaqi;LI Pengfei;LI Zhen(State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Center for Excellence in Deep Earth Science,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院广州地球化学研究所,同位素地球化学国家重点实验室,广东广州510640 [2]中国科学院深地科学卓越创新中心,广东广州510640 [3]中国科学院大学,北京100049

出　　处：《大地构造与成矿学》2024年第6期1416-1427,I0022-I0025,共16页Geotectonica et Metallogenia

基　　金：中国科学院国际合作项目(132744KYSB20200001);国家自然科学基金项目(42172237);广东省项目(2019QN01H101)联合资助。

摘　　要：蒙古-鄂霍茨克造山带位于中亚造山带中东部,其形成演化与蒙古-鄂霍茨克洋的俯冲消亡密切相关。在蒙古-鄂霍茨克造山带最西端的杭爱山地区,广泛发育泥盆纪-石炭纪增生杂岩,但同时期的岩浆活动却鲜有报道。为此,本研究以杭爱山地区拜德拉格微陆块中的石炭纪砂岩为研究对象,通过开展碎屑锆石年代学、微量元素及Hf同位素分析,示踪杭爱山地区岩浆活动历史。研究结果显示,砂岩中的碎屑锆石为典型的岩浆锆石,其U-Pb年龄主要集中在泥盆纪-石炭纪,峰值为~351 Ma,与泥盆纪-石炭纪杭爱-肯特增生杂岩中的碎屑锆石年龄谱相似,指示二者具有相似的物源供给。综合区域地质资料、碎屑锆石微量元素及Hf同位素特征,笔者推测杭爱山地区发育俯冲相关的泥盆纪-石炭纪岩浆岩,其与杭爱-肯特杂岩构成了西向的安第斯型俯冲体系,并为杭爱山地区石炭纪地层提供了物源供给。The development of the Mongol-Okhotsk Orogen in central Asia was controlled by the consumption of the Mongol-Okhotsk Ocean.However,the subduction history of the Mongol-Okhotsk Ocean is enigmatic.Here we focus on the Devonian to Carboniferous magmatism in the westernmost Mongol-Okhotsk Orogen(Hangay Mountains)and trace the history of magmatism in the area through detrital zircon from the Carboniferous sandstone in the Baydrag microblock.Our results show that detrital zircon from the Carboniferous sandstone has a typical magmatic origin and yields a major Devonian-Carboniferous age population with a peak at~351 Ma.Such an age pattern is comparable to the coeval Hangay-Hentey accretionary complex,suggesting a similar source.Combined with the previously mapped magmatic rocks in the Hangay Mountains,we consider that the Devonian to Carboniferous magmatic rocks are likely widespread,which provides detrital materials for coeval strata,and together with coeval the Hangay-Hentey accretionary complex to the east constitutes an Andean-type arc-trench system with westward subduction polarity.

关 键 词：中亚造山带 蒙古-鄂霍茨克造山带 杭爱山 岩浆弧 碎屑锆石 

分 类 号：P597[天文地球—地球化学] P542[天文地球—地质学]