大兴安岭中段索伦地区中侏罗统万宝组沉积环境及地球化学特征  

SEDIMENTARY ENVIRONMENT AND GEOCHEMISTRY OF THE MIDDLE JURASSIC WANBAO FORMATION IN SUOLUN AREA,MIDDLE DAXINGANLING MOUNTAINS

作　　者：施璐 唐振[1] 张渝金[1] 杨柳[1] 杜玉春 SHI Lu;TANG Zhen;ZHANG Yu-jin;YANG Liu;DU Yu-chun(Shenyang Center of China Geological Survey,Shenyang 110034,China;School of Resources and Civil Engineering,Northeastern University,Shenyang 110004,China)

机构地区：[1]中国地质调查局沈阳地质调查中心,辽宁沈阳110034 [2]东北大学资源与土木工程学院,辽宁沈阳110004

出　　处：《地质与资源》2022年第5期579-587,605,共10页Geology and Resources

基　　金：国家自然科学基金项目“大兴安岭中段龙江盆地中侏罗统地层新研究”(编号41702032);中国地质调查局项目“内蒙古1∶5万奈玛拉吉、巨里河、荷叶哈达幅区域地质调查”(编号DD20190039-03),“内蒙古1∶5万楞吉曼达坂、吉日根林场外站、西马拉吐、乌兰沼、巴彦套海幅区域地质调查”(编号DD20160048-02).

摘　　要：为了深入研究大兴安岭地区中生代断陷盆地构造背景,利用野外地质调查、岩石地球化学等方法,系统研究了索伦地区中侏罗统万宝组的沉积环境及地球化学性质.结果表明万宝组为一套分布于山间断陷盆地的陆相沉积碎屑岩建造,为辫状河三角洲相沉积环境.地球化学特征显示索伦地区万宝组富集大离子亲石元素(如Th、U、LREE)和Zr、Hf元素,亏损高场强元素(如Nb、Ta、P、Ti)和Ba、Sr元素,稀土元素配分曲线具有轻稀土富集的右倾特征.万宝组沉积物源主要来自中酸性岩浆岩源区,具有大陆岛弧构造背景特征,可能与蒙古-鄂霍茨克洋的南向俯冲弧后伸展作用有关.To further research the tectonic settings of Mesozoic fault basin in Daxinganling Mountains,on the basis of field geological survey and petrogeochemical analysis,this paper systematically studies the sedimentary environment and geochemical properties of Middle Jurassic Wanbao Formation in Suolun area.The results indicate that Wanbao Formation is a set of continental sedimentary clastic rocks distributed in the intermountain fault basin,with the sedimentary environment of braided river delta facies.The Wanbao Formation is geochemically characterized by enrichment of LILEs(Th,U,LREE),Zr and Hf,and depletion of HFSEs(Nb,Ta,P,Ti),as well as Ba and Sr.The REE patterns reveal right-dipping LREE enrichment.The sediment provenance mainly comes from acid-intermediate magmatic rocks,with the characteristics of continental island arc tectonic setting,which may be related to the southward subduction and back-arc extension of Mongolia-Okhotsk Ocean.

关 键 词：万宝组 沉积环境 物源分析 构造背景 大兴安岭中段 松辽盆地 

分 类 号：P595[天文地球—地球化学] P544[天文地球—地质学]