SEDIMENTARY FEATURES AND TECTONO-ENVIRONMENTAL SIGNIFICANCE OF THE MIOCENE STROMATOLITES IN WESTERN QAIDAM BASIN
Wen Zhifeng1, Zhong Jianhua1, Liu Yuntian2, Liu Zuhan3, Wu Kongyou1, Wang Guanmin1, Li Yong1
1. College of Earth Resources and Information, University of Petroleum, Dongying, Shandong 257061; 2. Qinghai Oilfield Branch Company, China National Petroleum Corp., Dunhuang, Gansu 370062; 3. Hunan University of Science and Technology, Xiangtan, Hunan 411201
The distribution and development with sedimentary characteristics of Miocene stromatolites in western Qaidam Basin were discussed in this paper. The stromatolites were mainly occurred in the Xiayoushashan Formation in an age of Early and Middle Miocene. According to the field survey and laboratory study, the stromatolites in the Qaidam Basin could be classified into four types, namely, dome-shaped, finger-shaped, column-shaped, and polygonal ones, which were characterized by their own special morphology, internal composition and textures, therefore, the stromatolitic kinds could be acted as an indicator of varied depositional environments. Based on the evidence from geochemistry, spore and fossils, it was presented that the stromatolites developed in a warm and salty lacustrine environment, with less terrigenous input. Compared with the modern stromatolites, the Neogene stromatolites in the Qaidam Basin was further elucidated in sedimentation and features. Combined with the Miocene sedimentary features and lacustrine stromatolites property, a close relation between the Qaidam Basin and the Qinghai-Tibet Plateau was further discussed, which thought the basins elevation during Early-Middle Miocene being less than 1 500 m.
Wen Zhifeng,Zhong Jianhua,Liu Yuntian et al. SEDIMENTARY FEATURES AND TECTONO-ENVIRONMENTAL SIGNIFICANCE OF THE MIOCENE STROMATOLITES IN WESTERN QAIDAM BASIN[J]. Chinese Journal of Geology, 2005, (4): 547-557.