西藏改则盆地扪挡勒剖面陆相红层时代归属再限定及其地层学意义  

CONSTRAINTS ON THE AGE OF CONTINENTAL RED BEDS OF THE GAIZE BASIN AT MENDANGLE AND ITS STRATIGRAPHIC SIGNIFICANCE

作　　者：韩芳 姜高磊[2] 李莎 韦一 王嘉轩 宋博文[6,7] 张克信[6,7] HAN Fang;JIANG Gao Lei;LI Sha;WEI Yi;WANG Jia Xuan;SONG Bo Wen;ZHANG Ke Xin(School of Earth Sciences,East China University of Technology,Nanchang 330013;Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences,Shijiazhuang050061;State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academyof Sciences,Nanjing 210008;Safety Engineering College,North China Institute of Science&Technology,Langfang 065201;School of Geography and Environment,Jiangxi Normal University,Nanchang 330022;Institute of Geological Survey,China University of Geosciences,Wuhan 430074;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]中国地质科学院水文地质环境地质研究所,河北石家庄050061 [3]中国科学院南京地质古生物研究所,现代古生物学和地层学国家重点实验室,江苏南京210008 [4]华北科技学院安全工程学院,河北廊坊065201 [5]江西师范大学地理与环境学院,江西南昌30022 [6]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [7]中国地质大学(武汉),生物地质与环境地质国家重点实验室,湖北武汉430074

出　　处：《地层学杂志》2022年第3期286-305,共20页Journal of Stratigraphy

基　　金：中国地质调查局项目(DD20221645);国家自然科学基金(42171010)共同资助。

摘　　要：由于缺乏可靠的古生物化石及定年材料,青藏高原腹地陆相红层的时代归属一直存在很大困难。本文通过碎屑锆石U-Pb测年与微体化石分析相结合的方法,对改则盆地扪挡勒剖面红层地层序列的沉积时代进行约束。结果显示红层中上段砂岩最年轻碎屑锆石LA-ICP-MS U-Pb年龄为46±1 Ma,约束了该段地层的年龄下限。红层上段地层获得的轮藻化石2属2种(含1未定种),具有中—晚始新世的微体化石组合特征。因此,结合最年轻碎屑锆石和微体化石组合,综合研究区红层下伏美苏组和上覆那丁错组及唢呐湖组地层的时代限定,将扪挡勒剖面红层地层序列的时代限定为中—晚始新世。Due to the lack of reliable fossil and age dating materials, it is still difficult to constrain the stratigraphic age of the continental red beds in the Central Tibetan Plateau. In this paper, we combined detrital zircon dating with microfossil assemblage to constrain the age of the red beds in the Mendangle section in the Gaize Basin. The youngest zircon age from a sandstone bed in the middle-upper part yields an age of ca. 46 Ma, providing a maximum deposition age of the sandstone bed. The charophyte microfossils extracted from the upper red beds consist of two species belonging to two genera. The red beds microfossil assemblages present the general characteristics of the Middle-Late Eocene species. Therefore, combined with the previous age constraint for the underlying Meisu Formation and overlying Nadingcuo Formation, Suonahu Formation, and the youngest age of detrital zircon and the characteristics of microfossil assemblage, we suggest that the age of the red beds is Middle Eocene-Late Eocene.

关 键 词：改则盆地 碎屑锆石 微体化石 陆相红层 始新世 

分 类 号：P534.61[天文地球—古生物学与地层学]