富有机质样品Re-Os同位素定年实验方法

Re-Os isotopic dating procedures for organic-rich samples

武鲁亚 金之钧 储著银 刘可禹

WU Luya JIN Zhijun CHU Zhuyin LIU Keyu

中国石油大学(华东) 地球科学与技术学院, 山东 青岛 266580 中国石化 石油勘探开发研究院, 北京 102206 中国科学院 地质与地球物理研究所 岩石圈演化国家重点实验室, 北京 100029 海洋国家实验室 海洋矿产资源评价与探测技术功能实验室, 山东 青岛 266071

School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China SINOPEC Petroleum Exploration and Production Research Institute, Beijing 102206, China State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266071, China

近年来，铼—锇（Re-Os）同位素体系在确定含油气系统烃源岩沉积年龄、烃类生成、运移、后期调整改造年龄（古油藏热裂解、硫酸盐热化学还原反应等）以及油源示踪方面取得了一系列成果。但是，富有机质样品的Re-Os同位素体系存在元素丰度低、赋存形式复杂、同位素体系封闭性影响因素以及Os同位素组成均一机制不清等诸多难题，进而导致其构建的等时线年龄误差相对较大。通过测年样品筛选、富有机质样品化学前处理、实验流程空白控制以及国际参考标样监控等4个方面，对现有的富有机质样品的Re-Os同位素分析测试全流程进行了总结与完善，可为拟开展含油气系统Re-Os定年工作的研究人员提高数据质量，构建理想的Re-Os等时线。

The rhenium-osmium (Re-Os) geochronometer is newly developed technology and has been regarded as a promising radiometric tool for the direct dating of the deposition of source rock, hydrocarbon generation, migration and consequent alteration (e.g., thermal cracking, thermochemical sulphate reduction), and oil-source correlation. However, the complex nature of Re-Os systems in organi-rich samples, including their relatively low elemental contents, multiple origins and occurrences, ambiguous homogenization mechanisms of 187Os/188Os and our limited understanding of the closed system of Re-Os systematics etc., often result in the relatively large uncertainties of obtained isochrones. In this paper, to improve their data quality and yield ideal Re-Os isochrons, the existing Re-Os isotopic analysis method was improved by the terms of sample selection and screening, chemical pretreatment, total analytical blank control and international reference material monitoring. Results showed that a comprehensive guide to researching working in Re-Os geochronology for petroleum system analysis can be available.

中国科学院战略性先导科技专项A类项目 XDA14010401;中国石油大学（华东）自主创新科研计划 17CX06032

https://doi.org/10.11781/sysydz202103513