Yuanzaoshan Gr
Type Locality and Naming
Beishan. The Yuanzaoshan Gr was named by Xiu Zelei et al. (1964). The type section is located in the Yuanzaoshan area in Subei Mongolia Autonomous County, Gansu Province.
Synonym: （圆藻山组）
Lithology and Thickness
The Yuanzaoshan Gr is a series (Yemajie Fm, overlain by Dahuoluoshan Fm) of carbonate-dolomite with abundant stromatolites, which are mainly dolomite, dolomitic marble (crystalline limestone) with marl interbedded with clastic rocks. The thickness of Yuanzaoshan Group is totally over 800 m.
Relationships and Distribution
Lower contact
The base of the Yuanzaoshan Gr is disconformable onto the Gudongjing Gr (upper part of Baihu Gr), or the Pingtuoushsan Fm (lower Mesoproterozoic).
Upper contact
The top is unconformable with the overlying Sinian tillite of the Xichangjing Fm. The Sinian tillite overlaps different formations of the Yuanzaoshan Gr
Regional extent
Beishan. Inner Mongolia and northernmost Gansu. The group is widely distributed in northern mountains in the boundary of Gansu, Xinjiang Weiwuerzhu Zizhiqu (Xinjiang Uygur Autonomous Region) and Inner Mongolia, which stretches from the west (Daquan) eastward through Luoyaohe, Pingtou, Shuangying, Dahuoluo and Yuanzao mountains to Yueya, Wangxus and Lanxin mountains of Ejin Qi, Inner Mongolia.
GeoJSON
Fossils
The type of Conophyton dominate the lower part (Pingtuoshan Fm) and the types of Gymnosolen, Inzeria dominte the upper part (Yemajie Fm, Dahuoluoshan Fm and Tongchangkou Fm).
Age
Depositional setting
Additional Information