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Geoscience ›› 2023, Vol. 37 ›› Issue (03): 733-744.DOI: 10.19657/j.geoscience.1000-8527.2021.153

• Experimental, Applied and Environmental Geochemistry • Previous Articles     Next Articles

Redox Sensitive Trace Element Compositions of the Shuinan Formation Black Shale in the Laiyang Sag: Controlling Factors of Organic Matter Enrichment

WANG Xuxue1(), ZHANG Xiangyu2,3, LI Shoujun1,3(), ZHANG Jiahao1, ZHANG Zhenyu1   

  1. 1. School of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266590, China
    2. College of Life Sciences, Linyi University, Linyi, Shandong 276000, China
    3. Key Laboratory of Stratigraphy and Paleontology, Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
  • Received:2021-05-12 Revised:2023-03-28 Online:2023-06-10 Published:2023-07-20

Abstract:

The geochemical characteristics of mudstone and shale in the saline lake basin are of great significance to the formation conditions and sedimentary environment of saline Source rock. To reconstruct the redox conditions and explore the controlling factors of organic matter enrichment in the Lower Cretaceous Laiyang Group of the Laiyang Sag, redox sensitive elements (RSEs, such as Mo, Cr, Zn, Cu, Ni, Co, V, As, U and Th) and total organic carbon (TOC) of mudstone and shale from this Group were analyzed. The results show that TOC content of mudstone in the Wawukuang and Zhifengzhuang Formations is relatively low, and that RSEs are not obviously enriched. TOC content of Shuinan Formation black shale increases sharply, and RSEs are enriched significantly, suggesting a weakly reducing environment. TOC content of the Longwangzhuang and Qugezhuang Formations decreases rapidly, and the RSE content is low, suggesting an oxidizing environment. Organic matter enrichment in the Shuinan Formation black shale is likely related to a combination of paleoclimate, paleoproductivity, paleosalinity and redox factors, among which paleoclimate is the main controlling factor of paleoproductivity, paleosalinity and redox conditions.

Key words: redox sensitive element, Laiyang Sag, Shuinan Formation, black shale, controlling factor of organic matter enrichment

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