The "Cretaceous Oceanic Red Beds（CORBs）" associated with "Oceanic Oxic Events" has become a hot topic for geologists around the world.CORBs are widespread in the northern Tethyan Himalaya.These CORBs consist of reddish to pink limestone, marlstones, shale, siltstone, and radiolarian cherts that are commonly assigned to the Chuangde Formation.Previous studies generally suggested that the CORBs in the Tethyan Himalaya are restricted to the slope and basinal environments（northern Tethys Himalayas sub-belt, NTH） and are entirely missing in the shelf depositional environments（southern Tethys Himalayas sub-belt, STH）.However, in our recent field geological survey, a set of shallow-marine red beds were found to occur in the Cretaceous Jiubao Formation in the Gyabuqing section, Guru, Yadong, where locates in STH（shelf depositional environments）, which challenges the previous views/understanding on the distribution range of the CORBs in south Tibet.The shallow-sea red beds in the Gyabuqing section are characterized by "monotonous color（light purple red）, single lithology（wackestone）, small thickness（about 5 m）, and with an age of Late Campanian（equivalent to the upper R.calcarata zone of planktonic foraminifera）.A total of 19 genera and 69 species of planktonic foraminifera have been identified from the Gangbacunkou and Jiubao formations in the Gyabuqing section.Four fossil zones of planktonic foraminifera have been recognized in ascending order as Dicarinella asymetrica, Globotruncanita elevata, Globotruncana ventricosa and Radotruncana calcarata, which give an age of late Santonian to Late Campanian of late Cretaceous.During Cretaceous, the Tethys Himalayas were generally characterized by a paleogeographic pattern of "deep north and shallow south" : The NTH was generally in a continental slope-oceanic basin environment with relatively deep water bodies and characterized by the prosperity of such skotoplankton as radiolarians and belemnites and the widespread development of the oceanic red beds.Conversely, the STH was generally in a relatively shallow continental shelf environment with almost no such skotoplankton as radiolarians and belemnites and oceanic red beds.The discovery of shallow-sea red beds in the Jiabuqing section is the first report of Cretaceous oceanic red beds in the STH, which is of great significance to the study of the genetic mechanism of Cretaceous oceanic red beds in southern Tibet.
类型: 国际会议
作者: Guobiao LI,Zichen Han,Tianyang WANG,Xinfa LI,Wenyuan ZHANG,Qi LI,Yuewei LI,Xuesong MA,Jun ZHAO,Wei SHI,Shengnan ZHAO
来源: 第一届亚洲古生物学大会—暨中国古生物学会成立90周年纪念 2019-11-17
年度: 2019
分类: 基础科学
专业: 生物学,地质学
单位: China University of Geosciences,BeijingState Key Laboratory of Environmental Geology and Biogeology,BeijingShandong geological and Mining Engineering Group Co., Ltd.State Key Laboratory of Environmental Geology and Biogeolog,Beijing
分类号: Q91;P534.53
页码: 126-127
总页数: 2
文件大小: 103k
下载量: 1
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