银额盆地石板泉西石炭系白山组碳酸盐岩地球化学特征及其环境意义  

Geochemical Characteristics and Sedimentary Environment of Carboniferous Baishan Formation Carbonate in Shibanquanxi of Yingen-Ejin Banner Basin

作　　者：史冀忠[1] 牛亚卓[1] 许伟[1] 宋博[1] 王宝文[1] Shi Jizhong;Niu Yazhuo;Xu Wei;Song Bo;Wang Baowen(Xi'an Ceuter.China Grological Survey,Xi'an 710054.China)

机构地区：[1]中国地质调查局西安地质调查中心,西安710054

出　　处：《吉林大学学报（地球科学版）》2021年第3期680-693,共14页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局项目(DD20190092)。

摘　　要：对银额盆地石板泉西石炭系白山组碳酸盐岩进行详细的地球化学分析,探讨各特征元素对古环境、古气候的指示意义。地球化学测试结果显示:除样品CH3外,其余样品主量元素中的Al及微量元素中的Ti、Zr、Th等典型陆源特征元素的含量较低,Y/Ho平均值为45.58,反映研究区白山组碳酸盐岩较少受陆源物质输入的影响;δCe与δEu、w(ΣREE)、(La/Sm)_N未见良好的相关性,也不具备Eu正异常,说明研究区白山组碳酸盐岩受成岩作用和热液作用的影响也较为有限。碳酸盐岩中所含微量元素主要为海水自生成因,能够反映原始沉积环境。根据特征元素对古水深、古盐度、古气候、古氧相和古水温进行研究,显示研究区白山组碳酸盐岩段虽然岩性较为单一,但其地球化学特征可以反映早晚的沉积古环境差异。研究区白山组碳酸盐岩总体经历了1个大的海侵海退旋回,沉积于正常海水,气候潮湿,弱氧化—弱还原环境,古水温为8.51~27.10℃,早期水温低,晚期水温升高。In this study,the major elements,trace elements,and rare earth elements of carbonate rocks from the Carboniferous Baishan Formation were analyzed,and the paleo-environment and paleo-climate of the Shibanquanxi of Yingen-Ejin Banner basin were discussed.The results of geochemical tests showed that the rock has low contents of typical continental elements,such as Al、Ti、Zr and Th,except for sample CH3;Combine with the ratio of Y/Ho(45.58),terrestrial input in the study area is limited.Additionally,there is no strong correlation betweenδCe andδEu,w(ΣREE),and(La/Sm)_N,and there is no positive Eu anomaly,indicating that the diagenesis and hydrothermal process had little impact on the sediments.The trace elements contained in the carbonate rocks are mainly self-generated by seawater,which can reflect the original sedimentary environment.The study of paleo-water depth,paleo-saltitude,paleo-climate,paleo-oxygen phase,and paleo-water temperature show that although the lithology of the carbonate section of the Baishan Formation is relatively simple,its geochemical characteristics can reflect the difference of sedimentary environment.The carbonate rocks of the Baishan Formation went through a huge transgression and regression cycle,and deposited in normal seawaterwith humid climate and weak oxidation-weak reduction environment.The paleo-water temperature was 8.51-27.10℃.The water temperature was low in the early stage,and increased in the late stage.

关 键 词：银额盆地 白山组 碳酸盐岩 地球化学 古环境 

分 类 号：P54[天文地球—构造地质学] P57[天文地球—地质学]