Geochemical characteristics of Ordovician strontium isotope in the Ordos basin

被引：0
作者：
Jiang S. [1 ,2 ,3 ,4 ]
Zhang Y. [2 ]
Huang W. [1 ,3 ,4 ]
Xing E. [2 ]
Gui B. [2 ]
Peng Y. [2 ]
Zhao H. [2 ]
Shang W. [2 ]
机构：
[1] School of Energy Resources, China University of Geosciences (Beijing), Beijing
[2] Key Laboratory of Saline Lake Resources and Environments, Institute of Mineral Resources, CAGS, Beijing
[3] Key Laboratory for Marine Reservoir Evolution and Hydrocarbon Abundance Mechanism, China University of Geosciences, Beijing
[4] Beijing Key Laboratory of Unconventional National Gas Geology Evaluation and Development Engineering, China University of Geosciences, Beijing
来源：
Dizhi Xuebao/Acta Geologica Sinica | 2019年 / 93卷 / 11期
关键词：
Conodont zones; Ordos basin; Ordovician; Strontium isotope stratigraphy;
D O I：
10.19762/j.cnki.dizhixuebao.2019196
中图分类号：
学科分类号：
摘要：
The research on Sr isotope of carbonate rocks in the Ordos basin mainly focuses on the identification and classification of diagenesis. In this study, the fifth Member of the Majiagou Formation (hereinafter referred to as Ma5) in the well Zhenjia-1 and Sandaokan Formation-Zhuozishan Formation in the western margin of the Ordos basin was selected as the research object. This study firstly reports Sr isotopic data of carbonate rocks which are not influenced by diagenesis. Based on the principle of Sr isotope stratigraphy, the characteristics of sedimentary environment were restored and the Ordovician stratigraphic framework was addressed. The following understanding has been obtained. (1) Ma5 Sr isotope of the well Zhenjia-1 is characterized by repeated vibration, but slightly increasing from bottom to top, with oscillation period coincidentally with evaporative rhythm. While Sr isotopes of the Sandaokan and Zhuozishan formations are characterized by moderate fluctuation and decrease generally. (2) Geological age of the Majiagou Formation can be assigned to the middle-late Darriwillian while the counterpart in the Sandaokan and Zhuozishan formations is earlier and is assigned to the early-middle Darriwillian. (3) Ma5 was deposited under the background of restricted platform-evaporation platform and its Sr curve differs from the global curve in Ordovician, suggesting that Sr isotope is more sensitive to the variation of paleoenvironment and could become an important indicator for regional paleoenvironmental comparison. The Sandaokan and Zhuozishan formations in the Zhuozishan area deposited under the background of open platform-carbonate slope and its Sr curve corresponds well with global curve. This study provides not only new fundamental data for global Sr isotope curve but also new evidence for comparison of the sedimentary and tectonic differences of strata in the Ordos basin. © 2019, Science Press. All right reserved.
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页码：2889 / 2903
页数：14
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