Discovery of Micro-And Nannofossils in High Grade Hydrocarbon Source Rocks of the Triassic Yanchang Formation Chang 7 Member in Ordos Basin
详细信息
- 责任者：Zhang Wenzheng (Institute of Exploration ; Development and Research of PetroChina Company Limited Changqing Oilfield Branch ; Xi’an 710018 ; China) ; Yang Hua
- 刊名：Acta Palaeontologica Sinica
- 出版年：2011
- 卷期：50(1)
- 关键词：烃源岩 ; source rocks ; 超微化石 ; nannofossils ; 鄂尔多斯盆地 ; Ordos Basin
- 页码：p.109-117
- 图表：4 illus., 2 plates, 1 table, 25 refs.
- 分类号：1003
- 出版序号：20120340
- issnNo：ISSN0001-6616
- isbnNo：CN32-1188/Q
摘要
Microfossils and nannofossils from 47 samples of Chang 7 Member high grade hydrocarbon oil shale source rocks of the Triassic Yanchang Formation, collected from Li 57 and other boreholes in the Ordos Basin, were studied using environmental SEM, SEM-EDX, and optical microscopy. The study validates the occurrence of carbonized primitive organic substances in the coeloms of four types of micro-and nannofossils (B, D, E, and F), and their preservation may ascribe to the existence of a thick collophane shell (B) and the rapid pyritization of thin walls of the organisms (D, E, and F). Catastrophic changes of the ecological system and the formation of an abnormal palaeoenvironment during the lake flooding stage corresponding to the formation of the Chang 7 Member may have been closely related to geological events, such as earthquakes, volcanic eruptions and hydrothermal activities at the bottom of the lake, which in turn would be associated with regional structural movements.