应用牙形刺色变指标探讨鄂尔多斯西缘北段奥陶系有机质成熟度

ON THE ORGANIC MATURITY OF THE ORDOVICIAN SYSTEM IN THE NORTHERN SECTION OF THE WESTERN MARGIN OF THE ORDOS BASIN BY USING CONODONT COLOR—ALTERED INDEX

于芬玲

Yu Fenling

华北石油地质局第三普查勘探大队, 咸阳 712000

NO. 3 General Survey and Exploration Party, North China Bureau of Petroleum Geology, MGMR

作者应用牙形刺色变指标(CAI)对鄂尔多斯西缘北段两个构造单元的奥陶系有机质成熟度进行了研究,结果表明:盆地部位的CAI=3～3.5,古地温约115～140℃,有机质演化阶段为成熟至高成熟;逆冲推覆构造带通喀拉高断块的CAI=1.5,古地温约43℃,有机质演化阶段尚处于未成熟。另据古生物和CAI资料,对通喀拉高断块形成于燕山运动的认识提出质疑。

In this paper,conodont color-altered index(CAI)is applied to the studies of the or-ganic maturity in the Ordovician system of the two structural units on the northern section of the western margin of the Ordors Basin.It is suggested that the value of CAI be 3 to 3.5 in the basin with paleogeotemperature of 115 to 140℃,and the evolutionary stage of organic matter can be attributed to mature to high-mature;while the value of CAI be 1.5 in the Tonggelagao fault block in overthrusting zone with a paleogeotemperature of 43℃,and the evolutionary stage of organic matter remains unmature.Moreover,the author of this paper questions the validity of the statement that the Tonggelagao fault block is formed by Yanshanian movement according to paleobiological and CAI reference.

https://doi.org/10.11781/sysydz199402180