Ordovician integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas  

作　　者：Xiang FANG Yong Yi ZHEN Guangxu WANG Xin WEI Zhongyang CHEN Yan LIANG Xuejin WU Wenjie LI Chao LI Renbin ZHAN Yuandong ZHANG 

机构地区：[1]State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,China [2]Geological Survey of New South Wales,W.B.Clarke Geoscience Centre,NSW 2753,Australia [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Earth Sciences》2024年第4期971-1004,共34页中国科学（地球科学英文版）

基　　金：supported by the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0706);the National Natural Science Foundation of China(Grant Nos.42030510,42002009,42102013);the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB26000000);the State Key Laboratory of Palaeobiology and Stratigraphy(Grant Nos.20201104,20221103);the Chinese Academy of Geological Sciences(Grant No.DD20221829)。

摘　　要：The Ordovician rocks on the Qinghai-Tibetan Plateau represent the oldest non-metamorphic strata,and are critical to understanding the history of regional geology and biotic evolution of the entire plateau.Strata of Floian,Darriwilian,Sandbian,Katian and Hirnantian are represented in the plateau with a hiatus of variable duration occurring underneath the basal Ordovician across the area.Five stratigraphical regions,including the Himalaya,Gangdise-Zayu,Qiangtang-Qamdo,Songpan-Garze,and Karakoram-Kunlun-Altun,are differentiated for the Ordovician strata,which are correlated with their equivalents in the Sibumasu,Indochina,Qaidam-Qilian,Tarim-Tianshan,and the Yangtze(western margin)stratigraphical regions.On the QinghaiTibetan Plateau,graptolites,conodonts,and cephalopods are the most common and useful fossils for the Ordovician biostratigraphy.The Ordovician biotas of the Qinghai-Tibetan Plateau bear some distinguishable palaeobiogeographical signatures,among which the cephalopods are characterized by the flourishing actinocerids of North China affinity in the Early-Middle Ordovician,and by the thriving lituitids and orthocerids of South China affinity in the Middle-Late Ordovician.Fossil occurrences and their palaeobiogeographical evolution provide critical evidence bearing on the reconstruction of the geological history of the Qinghai-Tibetan Plateau and surrounding terranes in northeastern peri-Gondwana.The stratigraphical successions of the Cambrian-Ordovician transition in the Himalaya and Lhasa and nearby Sibumasu terranes were significantly affected by the Kurgiakh Orogeny,which resulted in the extensive unconformity between the Ordovician and the underlying rocks in most areas of the Qinghai-Tibetan Plateau.In southern Xizang,a warm-water biota of Middle Ordovician age was recovered from oolitic limestones,suggesting a likely palaeogeographical location in low-latitudes near the equator.In the Himalaya and Sibumasu regions,the Upper Ordovician was typified by the occurrence of red carbonates with distinctive

关 键 词：ORDOVICIAN CHRONOSTRATIGRAPHY LITHOSTRATIGRAPHY BIOSTRATIGRAPHY PALAEOBIOGEOGRAPHY Qinghai-Tibetan Plateau 

分 类 号：Q911[天文地球—古生物学与地层学] P534.42[生物学—古生物学] P535