基于微量元素和稀土元素的物源分析——以金湖凹陷戴一段为例  

Source analysis based on trace elements and rare earth elements:an example from the lower Dainan Formation of Jinhu Sag

作　　者：王腾宇 毕天卓[2] 徐焕友[2] 张健伟[2] 田彦珍 钊新 冉硕 杨子艺 WANG Tengyu;BI Tianzhuo;XU Huanyou;ZHANG Jianwei;TIAN Yanzhen;ZHAO Xin;RAN Shuo;YANG Ziyi(College of Mining Engineering,North China University of Science and Technology,Tangshan 063210,China;Exploration and Development Research Institute of Jiangsu Oilfield Company,SINOPEC,Yangzhou 225009,China)

机构地区：[1]华北理工大学矿业工程学院,河北唐山063210 [2]中国石化江苏油田分公司勘探开发研究院,江苏扬州225009

出　　处：《复杂油气藏》2021年第4期36-46,共11页Complex Hydrocarbon Reservoirs

基　　金：河北省自然科学基金项目“古地貌要素与古气候耦合效应下陆相湖盆混合沉积研究——以南堡凹陷2号构造带为例”(D2020209003);河北省自然科学基金项目“混合沉积及其油气地质意义探讨——以饶阳凹陷蠡县斜坡沙河街组为例”(D2013209045)。

摘　　要：碎屑物质在风化、搬运和沉积过程中不稳定元素不断流失,稳定元素被保留,因此元素分析是定量化物源分析中常用的研究手段,尤其是微量元素和稀土元素的特征及其组合可有效地反映出当时的地质信息,从而提供较为准确的物源分析结果。通过对金湖凹陷戴一段泥岩微量元素和稀土元素进行La-Th-Sc、Th-Sc-Zr/10与La/Th-Hf三种构造背景判别图解、多元素物源判别曲线、稀土元素标准化曲线、稀土元素特征参数以及与周缘物源区地球化学特征对比的分析,对研究区的构造背景、母岩特征以及搬运方向进行了综合研究。分析结果:出源区大地构造背景为靠近活动大陆边缘的大陆岛弧,金湖凹陷周缘源区母岩以长英质物质为主,古老沉积物为辅。通过系统的物源体系研究,认为金湖凹陷的汊涧斜坡主要受到来自研究区西部张八岭隆起方向源区的影响;杨村断裂带下降盘主要受到研究区南部天长低凸起方向的源区影响;三河斜坡主要受到来自研究区西北部建湖隆起方向源区的影响;石港断裂带下降盘主要受到来自研究区东部菱塘桥—柳堡低凸起方向源区的影响,其中断裂带南部受到来自菱塘桥方向源区的影响更为显著。研究结果可为金湖凹陷戴一段下一步沉积相研究及有利砂体预测提供借鉴。In the process of weathering,transportation,and deposition,unstable elements in the detrital material are continuously lost,and stable elements are retained.Therefore,elemental analysis is a commonly used research method in quantitative source analysis,especially the characteristics and combinations of trace elements and rare earth elements can effectively reflect the geological information at the time of deposition,thereby providing more accurate provenance analysis results.According to the trace elements and rare earth elements of the mudstone in the lower Dainan Formation of the Jinhu Sag,it was analyzed the three structural background discrimination diagrams of La-Th-Sc,Th-Sc-Zr/10 and La/Th-Hf,the multi-element provenance discrimination curve,the standardized curve of rare earth elements,the characteristic parameters of rare earth elements,and compared with the geochemical characteristics of the surrounding provenance area.A comprehensive study was conducted on the structural background,parent rock characteristics,and transportation direction of the study area.The analyses show that the geotectonic background of the study area is a continental island close to the active continental margin.The source area around the Jinhu Sag is dominated by felsic materials,and supplemented by ancient sediments.Through systematic provenance system research,it is believed that the Chajian slope in Jinhu Sag is mainly affected by the source area from the Zhangbaling uplift in the western part of the study area;the descending plate of the Yangcun fault zone is mainly affected by the source area from the Tianchang low uplift in the southern part of the study area;the Sanhe slope is mainly affected by the source area from the Jianhu uplift in the northwest of the study area;the descending disk of the Shigang fault zone is mainly affected by the source area from the Lingtangqiao-Liubao low uplift in the eastern of the study area,in which the southern part of the fault zone is more significantly affected by the source area from the

关 键 词：物源分析 微量元素 稀土元素 戴一段 金湖凹陷 

分 类 号：P622[天文地球—地质矿产勘探]