Earth Science Frontiers ›› 2009, Vol. 16 ›› Issue (6): 96-103.

• Article • Previous Articles     Next Articles

Organic geochemical characteristics of anoxic levels in the Cretaceous Qingshankou Formation of Songliao Basin.

KONG Hui, HUANG Yong-Jian, HUANG Qing-Hua, ZHANG Wen-Jing, XIE Lei, LIU Hua-Gong, XIE Xiao-Yun   

  1. 1,Huang Yongjian2,Huang Qinghua1,Zhang Wenjing1,Xie Lei3,Liu Xuehong4,
    Xie Xiaoyun11Exploration and Development Research Institute of Daqing Oilfield Company Ltd., Daqing 163712, China
    2Research Center for Tibetan Plateau Geology, China University of Geosciences(Beijing), Beijing 100083, China
    3No1 Company of Well Log, Daqing Drilling Engineering Corporation of Daqing Oilfield Company Ltd., Daqing 163411, China
    4No1 Oil Production Company of Daqing Oilfield Company Ltd., Daqing 163162, China
  • Received:2009-06-25 Revised:2009-11-08 Online:2009-12-16 Published:2009-12-10

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Abstract:

 The Songliao Basin was a big lake during the midCretaceous, where dark mudstones and shales of the Qingshankou Formation were distributed in the basin. The dark mudstones and shales in the Member 1 of the Qingshankou Formation are of high organic carbon and low diasteranes contents. Organic geochemical characteristics are illustrated by biomarkers of 28, 30bisnorhopane and gammacerane, and positive excursion of kerogen isotopes. It is suggested that the dark mudstones and shales in the Member 1 of the Qingshankou Formation are the products of lake anoxic event in the extreme greenhouse climate period. Based on the study of biostratigraphy and anoxic eventstratigraphy, we propose that the Qingshankou Formation may correspond to the oceanic anoxic event at the CenomanianTuronian boundary in the Cretaceous, and the age of the Qingshankou Formation in the Songliao Basin is the Late Cenomanian to the Early Turonian.

Key words: Key words: dark shales; carbon isotope; biomarkers; anoxic events; Qingshankou Formation; Cretaceous; Songliao Basin