Fractionation characteristics of magnesium isotope in the ancient weathering crust

作     者：Jia-Qi Yang Jun-Tao Zhang Zhi-Liang He Ni-Na Luo Xiao-Hui Jjin Tao Zhang Ning Gu Kang-Jun Huang jian Gao 

作者机构：School of Energy ResourcesChina University of GeosciencesBeijing100083China SINOPEC Exploration and Production Research InstituteBeijing100083China China Petrochemical Corporation Ltd.Beijing100728China Key Laboratory of Deep Geology and ResourcesSINOPECBejing102206China Chongqing Gas Field of Petro China Southwest Oil and Gas Field CompanyChongqing400021China Shaanxi Key Laboretory of Early Life and EnvironmentsDepartment of GeologyNorthwest UniversityXi'anShaanxi710069China 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2023年第20卷第3期

页      面：1446-1457页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the National Natural Science Foundation of China(42072177) National Natural Science Foundation of China(U19B6003) Frontier Project of Chinese Academy of Sciences(XDA14010201) 

主　　题：Magnesium isotope Dolomitization mode Weathering Ancient weathering crust Ordos Basin 

摘      要：Weathering has always been a concerned around the world,as the first and most important step in the global cycle of elements,which leads to the fractionation of isotopes on the scale of geological *** Middle Ordovician Majiagou Formation in Daniudi area of the Ordos Basin had experienced weathering for130 *** thin section observation,major and trace element analysis,carbon,oxygen,and magnesium isotopes composition analysis,the dolomitization modes and weathering of ancient dolo-mite in Daniudi area were analyzed in *** results showed that the Sabkha and brine-reflux dolomitization modes had developed,and the Mg isotopes in different layers of the karst crust were fractionated by various *** vertical vadose zone was affected by weathering,the Mg isotope of dolomite(δ^(26)Mgdol)showed a downward decreasing trend;the horizontal underflow zone was controlled by diagenesis and formation fluid,δ^(26)Mgdol showed a vertical invariance and negative;the main reason for Mg isotope fractionation in the deep slow-flow zone was the brine-reflux dolomitization mode during early burial period,which showed a vertical downward ***,the Mg isotope characteristic data of the ancient weathering crust were provided and the process of Mg isotope frac-tionationinthekarstcrust was explained.