Discovery of Paleogene marine stratum along the southern side of Yarlung-Zangbo suture zone and its implications in tect
The Jiachala Formatiom is a new lithostratigraphic unit set up in this paper. This is the first report on the Paleogene marine sequences and microfaunas in Gyangze to the southern side of the Yarlung-Zangbo suture zone. On the basis of fossil abundance, species diversity, dominant species and first and last occurrences of key species, three dinoflagellate assemblages and three polynological assemblages were recognized in the Jiachala Formatiom. They are in ascending order as follows: Apectodinium quinquelatum-Apectodinium hyperacanthum, Canningia chinensis-Palaeoperidinium pyrophorum and Cymatiosphaera reticulosa-Samlandia chlamydophora dinoflagellate assemblages, and Arliaceoipollenites baculatus-Anacolosidites subtrudens, Aglaoreidia cyclops-Pinuspollenites microinsigis, and Elaeangnacites asper-Ilexpol- lenites iliacus polynological Assemblages. According to the assemblages, the age of the Jiachala Formation is referred to Paleocene-early Eocene. The preliminary study on the Jiachala Formation shows that this group of Paleogene deposits accumulated in an underfilled peripheral foreland basin which was in response to the load of the crust thickening resulted from the Asia-India collision. The stratigraphic evidences provided by the evolution of foreland basin indicate that the India-Asia initional collision should occure near the Cretaceous/Paleogene boundary. The development and evolution of the southern Tibet foreland basin was under the control of the stress field from the subduct-collision between India and Asia and the structure pattern of the basement. The withering of Tethys Sea might occur after early Eocene in the Gyangze basin and should be after Priabonian of late Eocene in southern Tibet.
作 者： Li Guobiao WAN Xiaoqiao LIU Wencan LIANG Dingyi Hyesu Yun 作者单位： Li Guobiao,WAN Xiaoqiao,LIU Wencan,LIANG Dingyi(China University of Geosciences, Beijing 100083, China)Hyesu Yun(Chungnam National University, Daejon, 305-350, Korea)
刊 名： 中国科学D辑（英文版） SCI 英文刊名： SCIENCE IN CHINA SERIES D(EARTH SCIENCES) 年，卷(期)： 2005 48(5) 分类号： P5 关键词： Paleogene marine strata Jiachala Formation microfossils underfilled peripheral foreland basin initional collision Gyangze