西藏拉萨地块中部扎布耶茶卡一带中二叠世■类动物群及其古生物地理意义  

MIDDLE PERMIAN FUSULINE FAUNAS FROM THE ZHABUYE AREA, CENTRAL LHASA BLOCK, TIBET AND THEIR PALAEOBIOGEOGRAPHIC IMPLICATIONS

作　　者：琚琦 张以春[1] 乔枫 徐海鹏 JU Qi;ZHANG Yi-chun;QIAO Feng;XU Hai-peng(State Key Laboratory of Palaeobiology and Stratigraphy ,Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049;School of Earth Sciences and Engineering ,Nanjing University ,Nanjing 210023, China)

机构地区：[1]现代古生物学和地层学国家重点实验室,中国科学院南京地质古生物研究所,中国科学院生物演化与环境卓越创新中心,南京210008 [2]中国科学院大学,北京100049 [3]南京大学地球科学与工程学院,南京210023

出　　处：《古生物学报》2019年第3期324-341,共18页Acta Palaeontologica Sinica

基　　金：国家自然科学基金重大研究计划重点项目(91855205);第二次青藏高原综合科学考察研究(2019QZKK0706);中国科学院战略性先导科技专项(B类)(XDB26000000);中国科学院青年创新促进会项目(2016282)联合资助

摘　　要：对拉萨地块中部扎布耶茶卡北岸的两个剖面开展(虫筳)类动物群系统古生物学及古生物地理研究。鉴定出(虫筳)类 6 属 16 种,包括Yangchienia tobleri Thompson,Yangchienia haydeni Thompson,Chusenella brevipola (Chen),C. schwagerinaeformis Sheng,C. cf. brevis (Chen),C. sp.,Nankinella rarivoluta Wang,Sheng and Zhang,N. complanata Wang,Sheng and Zhang,Kahlerina tenuitheca Wang,Sheng and Zhang,K. pachytheca Kochansky-Devidé and Ramovs,Verbeekina americana Thompson, Wheeler and Danner,V. tenuispira Sheng,Neoschwagerina cheni Sheng,N. colaniae Ozawa,N. craticulifera (Schwager),N. brevis Thompson,Wheeler and Danner。基于Kahlerina属的出现及Neoschwagerina属的厚壁壳体以及第二旋向副隔壁发育较弱的形态特征,判断其时代为二叠纪瓜德鲁普世(Guadalupian)沃德期(Wordian)。该(虫筳)类动物群面貌可与拉萨地块的狮泉河地区、措勤夏东地区、申扎地区、林周地区等对比。拉萨地块从中二叠世开始普遍出现暖水(虫筳)类动物群,这与印度板块北缘特提斯喜马拉雅地区中、晚二叠世时期均以冷水的腕足生物群为主所反映的水体性质有明显的差异。这表明拉萨地块和喜马拉雅地区在晚三叠世之前仍然连在一起的可能性并不大,拉萨地块可能在瓜德鲁普世沃德期以前已经脱离冈瓦纳大陆。This study describes the Guadalupian (Middle Permian) fusulines from the northern Zhabuye area in the Lhasa Block and discusses their palaeobiogeography. In total, the fusuline fauna comprises 6 genera and 16 species, including Yangchienia tobleri Thompson, Yangchienia haydeni Thompson, Chusenella brevipola (Chen), C. schwagerinaeformis Sheng, C. cf. brevis (Chen), C. sp., Nankinella rarivoluta Wang, Sheng and Zhang, N. complanata Wang, Sheng and Zhang, Kahlerina tenuitheca Wang, Sheng and Zhang, K. pachytheca Kochansky-Devidé and Ramov?, Verbeekina americana Thompson, Wheeler and Danner, V. tenuispira Sheng, Neoschwagerina cheni Sheng, N. colaniae Ozawa, N. craticulifera (Schwager) and N. brevis Thompson, Wheeler and Danner. This fauna suggests a Wordian age, as evidenced by the presence of Kahlerina and the thick spirotheca and less-developed secondary transverse septula in Neoschwagerina species. The fauna from the Zhabuye area is correlatable with the contemporaneous faunas from other regions in the Lhasa Block including the Shiquanhe area, the Xiadong area in Tsochen County, Xainza County and Lhunzhub County. The synchronous appearances of Guadalupian warm-water fusuline faunas in the whole Lhasa Block exhibit a pronounced difference in palaeobiogeography from the Tethys Himalaya region with persistent cold-water brachiopod faunas during the middle and late Permian. It is unlikely that the Lhasa Block and the Tethya Himalaya region adjoined together before the late Triassic. Therefore, it is considered that the Lhasa Block has been separated from the Gondwanaland by Wordian time.

关 键 词：(虫筳)类动物群 古生物地理 拉萨地块 西藏 

分 类 号：Q915[天文地球—古生物学与地层学]