欢迎访问《高校地质学报》官方网站,今天是
分享到:

J4

• 文章目录 • 上一篇    下一篇

西藏岗巴晚白垩世有孔虫动物群与海平面变化

赵文金1 2   

  1. 1. 中国地质大学(北京) 地球科学与资源学院 10083; 2. 中国科学院古脊椎动物与古人类研究所,北京100044;
  • 收稿日期:2001-03-20 修回日期:2001-03-20 出版日期:2001-03-20 发布日期:2001-03-20

Late Cretaceous Foraminiferal Faunas and Eustatic Change in Gamba Area,Southern Tibet

ZHAO Wen-jin   

  1. China University of Geosciences, Beijing 100038, China
  • Received:2001-03-20 Revised:2001-03-20 Online:2001-03-20 Published:2001-03-20

摘要: 西藏南部岗巴地区上白垩统的有孔虫动物群十分丰富,经鉴定共有52属130种。根据岩性,该地区上白垩统可以划分出三个最基本的岩石地层单位:冷青热组、岗巴村口组及宗山组。依据其中有孔虫的形态结构、生态环境、系统演化及地史分布等特征,可以划分出五个主要的有孔虫动物群,Rotalipora动物群,Whiteinella-Helvetoglobotruncana动物群,Dicarinella-Marginotruncana动物群,Globotruncana-Globotuncanita动物群及Orbitoides-Omphalocyclus动物群。这五个有孔虫动物在晚白垩世相继绝灭,其绝灭与古水深有着十分密切的关系,主要是受海平面变化的影响。

Abstract: The Zongshan section in Gamha of southern Tibet has long been considered as the standard section for the Cretaceous of the Tethyan Himalayas The Late Cretaceous strata are well exposed in this area and contain abundant foraminiferal fossils,from which 130 species of 52 genera have been identified. The rocks are mostly marine carbonates. Systematic studies of the microfauna and petrology have been conducted to establish a new stratigraphic framework for this area and the relationship between the foraminifera1 faunas and the sea level changes.The Late Cretaceous strata in this area can be subdivided into three Formations, which are(in ascending order)the Lengqingre Formation,Gangbacunkou Formation and Zongshan Formation. They are roughly of the Cenomanian to early Turonian,middle Turonian-Santonian and Campanian-Maastrichtian age. Ten planktonic foraminiferal zones were recognized,which can be correlated with similar zones in Pakistan, Europe and America In addition,5 foraminlferal faunas, represented by Rotalipora fauna, Whiteinella-Helvetoglobotruncana fauna ,Dicarinella-M arginotruncana fauna ,Globotruncana-Globotruncanita fauna and Orbitoides-Omphalocyclus fauna,can be recognized. The evolution of the foraminiferal faunas in this area occurred mainly in response to the eustatic changes which have affected biological niche of the microplankton.