沉积岩有机碳同位素组成测定的前处理方法研究  

A Pre-Treatment Method for the Determination of Organic Carbon Isotope Composition in Sedimentary Rocks

作　　者：杨宗彩 徐学敏[1] 杨佳佳[1] 沈斌 苑坤 张小涛 许智超 翟佳 YANG Zongcai;XU Xuemin;YANG Jiajia;SHEN Bin;YUAN Kun;ZHANG Xiaotao;XU Zhichao;ZHAI Jia(National Research Center for Geoanalysis,Beijing 100037,China;Oil and Gas Resources Survey,China Geological Survey,Ministry of Natural Resources,Beijing 100083,China)

机构地区：[1]国家地质实验测试中心,北京100037 [2]中国地质调查局油气资源调查中心,北京100083

出　　处：《岩矿测试》2024年第6期847-857,共11页Rock and Mineral Analysis

基　　金：国家自然基金青年基金项目(41702159);中国地质调查局地质调查项目(DD20243553)。

摘　　要：沉积岩的有机碳同位素研究是地质学领域的重要内容,可为地质历史时期的古环境重建、古气候变化解析、碳循环过程理解以及能源资源勘探开发提供重要信息。由于沉积岩中的有机碳主要以干酪根的形式赋存,因此,在获取沉积岩有机碳同位素值之前,需要先对岩石样品开展干酪根提取预处理。提取过程需使用大量危险化学品,制备流程长且面临化学品使用受限等诸多挑战。因此,在实际工作中,亟需开发一种更为便捷、环保的前处理方法。本文建立了一种简易的酸处理方法,实验选取110件不同岩性(灰岩、页岩、油页岩)和不同有机碳含量范围(0.83%~35.33%)的沉积岩样品进行该前处理方法与传统干酪根提取前处理方法的比对实验。结果表明,对于94%的样品,本次建立的前处理方法和干酪根提取方法获得的碳同位素值差值均小于1.0‰,满足行业标准方法重复测定的偏差要求。表明该前处理方法可以有效地实现沉积岩样品中有机碳的分离,进而准确获取有机碳同位素值这一关键地质参数。而且,样品的有机碳含量及岩性未对测定结果产生明显影响,显示该方法对常规地质样品的适用性,可满足地质勘探调查工作需求。The organic carbon in sedimentary rocks is mainly in the form of kerogen,and it is necessary to extract kerogen from samples before obtaining the organic carbon isotope value.The extraction process requires a significant quantity of hazardous chemicals and a long preparation process.Therefore,in daily work,there is an urgent need to develop a more convenient and environmentally friendly pre-treatment method.A simple acid treatment method was established,and 110 sedimentary rock samples with different lithology(limestone,shale,oil shale)and different organic carbon content range(0.83%−35.33%)were selected for comparison experiments of two pretreatment methods.The results show that for 94%of the samples,the difference of carbon isotope values obtained by the acid pretreatment method established in this study and the kerogen extraction method was less than 1.0‰,which met the deviation requirements for repeated measurements,indicating that this pretreatment method can be used to accurately obtain the key geological parameter of an organic carbon isotope value.Furthermore,the organic carbon content and lithology of the samples does not influence the results,demonstrating the applicability of this method to typical geological samples and fulfilling the requirements of geological exploration and investigation.

关 键 词：碳同位素 沉积岩 前处理方法 酸处理 干酪根 

分 类 号：P597.2[天文地球—地球化学]