下扬子皖南地区下寒武统荷塘组页岩地球化学特征及地质意义  

Geochemical characteristics and significance of the shale of Lower Cambrian Hetang Formation in the southern Anhui Province of Lower Yangtze area

作　　者：姚红生[1] 何希鹏[1] 汪凯明[2] YAO Hongsheng;HE Xipeng;WANG Kaiming(East China Branch of Sinopec,Nanjing 210019,China;Research Institute of Exploration and Development,East China Branch of Sinopec,Nanjing 210019,China)

机构地区：[1]中国石化华东油气分公司,南京210019 [2]中国石化华东油气分公司勘探开发研究院,南京210019

出　　处：《海洋地质前沿》2022年第4期32-41,共10页Marine Geology Frontiers

基　　金：“十三五”国家科技重大专项(2017ZX05036-003-009)。

摘　　要：中国南方下寒武统富有机质黑色页岩发育,具有分布面积广、沉积厚度大、有机碳含量高等有利条件,蕴藏着丰富的页岩气资源潜力,有望成为页岩气“增储上产”的重要区域。以下扬子地区下寒武统荷塘组页岩气首口参数井-XY1井为研究对象,利用岩芯资料和地球化学分析测试数据,探讨了研究区元素地球化学特征与古环境意义。研究结果表明:主量元素SiO_(2)、K_(2)O相对富集,其他元素均不同程度地相对亏损;微量元素Sr、Rb亏损,Ni、Co、Ba元素明显富集。荷塘组黑色页岩属大陆边缘沉积,硅质主要来源于硅质生物,为生物成因,沉积时期气候温暖潮湿,为咸水-高盐水体环境,有利于有机质的形成,沉积期具有较高的古生产力,水体环境以贫氧-厌氧为主,有利于有机质保存。The Lower Cambrian organic-rich black shale is well developed in southern China,which is wide in distribution,large in thickness and high in total organic carbon.It has great resource potential of shale gas and is expected to be an important succeeding field to meet the future increase in shale gas demand.This paper is devoted to the first parameter well XY1 of the Lower Cambrian Hetang Formation shale gas in the lower Yangtze area.Using cores and geochemical data,element geochemical characteristics and their paleoenvironmental significance are studied.The results show that the major elements SiO;and K;O are relatively rich,and the others are lower to certain extent.As for trace elements,Sr and Rb are depleted,and the elements of Ni,Co and Ba are obviously enriched.The black shale of Hetang Formation is a kind of continental margin deposits.Silica mainly came from siliceous organisms under a warm and humid climate,and deposited in saline water,which is favorable to the deposition of organic matter.It is inferred that paleoproductivity of the Hetang Formation is high.The anaerobic water environment is conducive to the preservation of organic matter.

关 键 词：荷塘组 黑色页岩 元素地球化学特征 地质意义 下扬子 

分 类 号：P736.4[天文地球—海洋地质] P618.13[天文地球—海洋科学]