缝洞充填物地球化学特征及环境指示意义——以塔里木盆地富满地区中奥陶统一间房组为例

为了明确塔里木盆地富满油田奥陶系一间房组缝洞充填物所蕴藏的环境信息，对富满地区中奥陶统一间房组缝洞充填物微量元素测试，并对所测稀土元素进行北美页岩标准化。结果表明稀土元素标准化曲线整体呈右倾趋势，Ce呈弱亏损，Eu显示强烈正异常。Sr、Al和Ti元素显示缝洞充填物受陆源碎屑物质扰动影响，Sr/Ba整体偏低且均小于1,推断缝洞充填物来源于淡水环境，Fe/Ti、 Al/(Al+Fe+Mn)、Cu+Pb+Zn及Fe+Mn/Ti值表明缝洞充填物受热液活动影响较小，U/Th、Ni/Co和V/Cr比值推测缝洞充填物形成于氧化环境下。综合研究表明，富满地区中奥陶统一间房组缝洞充填物主要形成于氧化条件下的大气淡水环境，主要受陆源物质扰动且受深部热液影响较少。

Geochemical Characteristics and Environmental Implications of Fracture-cave Fillings

Through the trace elements test of the Middle Ordovician YiJianfang Formation fracture-cave fillings in Fuman area of Tarim Basin, and the standardization of the measured rare earth elements in North American shale, it is found that the overall curve shows a rightward trend, the Ce shows a weak deficit, and the Eu shows a strong positive anomaly. The Sr, Al and Ti elements showed that the fillings were affected by terrigenous detritus disturbance, and the Sr/Ba was generally low and all were less than 1. It was inferred that the fillings were from freshwater environment. The Fe/Ti, Al/(Al+Fe+Mn), Cu+Pb+Zn and Fe+Mn/Ti values indicated that the fillings were less affected by hydrothermal activity. The ratios of U/Th, Ni/Co and V/Cr suggested that the filling was formed in the oxidized environment. The comprehensive study shows that the fillings of the middle Ordovician Yijianfang Formation are mainly formed in the atmospheric fresh water environment under oxidized conditions, and are mainly disturbed by terriglogenic materials and less affected by deep hydrothermal solution.