Stratigraphic framework and sedimentary evolution during the Cryogenian-Ediacaran transition in northeastern Sichuan Basin,South China  

作　　者：Yi Zhang Hong-Wei Kuang Yong-Qing Liu Qiang Shi Dong-Ge Wang Ke-Ning Qi Yu-Chong Wang Da-Wei Qiao Xiao-Shuai Chen Li-Zhi Wu Meng Tian Long Chen Yi Wei Liao-Yuan Song Jian Li Zi-Gang Wu Yun-Qian Liu Xuan-Chun Liu An-Qing Chen Zhi-Wei Liao 

机构地区：[1]Institute of Geology,Chinese Academy of Geological Sciences,Beijing,100037,China [2]State Key Laboratory of Coal Mine Disaster Dynamics and Control,School of Resources and Safety Engineering,Chongqing University,Chongqing,400044,China [3]No.205 Geological Team,Chongqing Bureau of Geology and Minerals Exploration,Chongqing,401121,China [4]Chongqing Institute of Geological Survey,Chongqing,401122,China [5]Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources,Chengdu University of Technology,Chengdu,610059,Sichuan,China

出　　处：《Petroleum Science》2024年第2期823-835,共13页石油科学（英文版）

基　　金：supported by the China Geological Survey project(DD20221649);the National Natural Science Foundation of China(Nos.U19B6003,42072135,and 42172119);Chongqing Research Program of Basic Research and Frontier Technology(Grant No.cstc2021jcyj-msxm X0023);Open Fund(DGERA 20211105)of Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources,Chengdu University of Technology。

摘　　要：The northeastern Sichuan area in the northern Yangtze margin has unique Ediacaran geological records,especially the Doushantuo Formation(DST),and become a hot research area in recent years.However,the Cryogenian-Ediacaran(C-E)boundary has not been precisely identified,which restricts the in-depth study of geological information during this crucial transitional period and is unfavorable for a systematic and complete understanding of the Yangtze Block and even the global paleogeographic pattern.This study conducted stratigraphy,sedimentology,and chronostratigraphy to establish the stratigraphic framework and sedimentary evolution of the C-E transition strata in northeastern Sichuan.The results showed that the Ediacaran sediments,without the cap dolomite,unconformably overlaid the Cryogenian sediments in the studied area.The Member II of the DST,characterized by 50-160 m of red-green sandstone(approximately equivalent to the original Chengkou“Guanyinya Formation”),directly overlaid the Cryogenian sediments and displayed a 623±2.3 Ma maximum depositional age from the detrital zircon U-Pb dating.Regional stratigraphic correlations indicate that the C-E transition strata in northeastern Sichuan had a consistent lithological association and sedimentary sequence characteristics but differed from the Three Gorges.Typically,the upper Nantuo massive glacial diamictites transition to the icebergs rafted lonestone-bearing mudstones at the top,then change upward to DST barrier coast sandstones.The proposed DST of the northeastern Sichuan Basin was divided into three lithostratigraphic members without the regional Member I cap dolomite:(i)Member II purple-red,gray-green sandstone strata,(ii)MemberⅢblack mudstone strata,and(iii)Member IV P-Mn bearing strata.During the C-E transition,the study area experienced(i)the global deglaciation stage in the terminal Marinoan glaciation and(ii)the filling-leveling up stage with clastic rocks in the early Ediacaran.Overall,the early Ediacaran of northeastern Sichuan succeeded the pal

关 键 词：Marinoan glaciation Doushantuo formation Cap dolomite Deglacial and coastal deposits Detrital zircon U-Pb dating 

分 类 号：P618.13[天文地球—矿床学]