藏南桑单林剖面晚古新世放射虫动物群及其地质意义  

UPPER PALEOCENE RADIOLARIAN FAUNA FROM THE SANGDANLIN SECTION,SOUTHERN TIBET,CHINA AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：王学恒[1,2] 罗辉[1] 许波[1] 祝幼华[1] 陈迪舒[1,2] 刘实佳 

机构地区：[1]中国科学院南京地质古生物研究所,南京210008 [2]中国科学院大学,北京100049

出　　处：《微体古生物学报》2016年第2期105-126,共22页Acta Micropalaeontologica Sinica

基　　金：中国科学院战略性先导科技专项(B类)子课题(XDB03010102);国家自然科学基金(41402016;40572007)联合资助~~

摘　　要：本文描述的放射虫化石新材料发现于藏南桑单林剖面中部灰绿色硅质岩和硅质泥岩层段,共计21属33种,含5个未定种。通过与北大西洋和南太平洋古新世放射虫化石带进行对比,该放射虫动物群可归为晚古新世RP6 Bekoma campechensis带和RP7 Bekoma bidartensis带,时代为Selandian期至Thanetian晚期。综合剖面岩相、构造特征和已报道的放射虫化石组合,本文认为桑单林剖面是一套构造成因的混杂堆积,可能代表了新特提斯洋俯冲和后期印度-欧亚板块碰撞过程中形成的增生杂岩系。区域上,仲巴-萨嘎-江孜一带发现的晚古新世放射虫动物群和海相玄武岩表明,在晚古新世最晚期(大约56 Ma),西藏南部还存在着较大规模的深海沉积。The newly discovered radiolarian fossils were extracted from grey-green cherts and siliceous mudstones that exposed in the middle part of the Sangdanlin section, southern Tibet, China. 33 species belonging to 21 genera inclu ding 5 indeterminate species have been systematically described in this paper. By comparing with the Paleocene radiolarian zonations of the North Atlantic and the South Pacific, this radiolarian fauna can be assigned to the Upper Paleocene （RP6 Bekoma campechensis zone and RP7 Bekoma bidartensis zone, from the Selandian to the latest Thanetian）. Based on lithofacies, geological structures and the previously reported radiolarian fossil assemblages, this study sug- gests that the Sangdanlin section is a typical tectonic m61ange, which may represents the accretionary complex that formed during the process of Neo-Tethys subduction and the India-Asia collision. According to the Upper Paleocene radiolarian faunas and the contemporary basalts recognized along the Zhongba-Saga-Gyangze areas, we believe that there still existed a large scale of deep marine sediments in the southern Tibet during the latest Paleocene （- 56 Ma）.

关 键 词：放射虫 古新世 新特提斯洋 雅鲁藏布江缝合带 藏南 

分 类 号：Q915[天文地球—古生物学与地层学]