华北克拉通北缘中元古界杨庄组碳酸盐岩地球化学特征及其地质意义  

Geochemical characteristics and geological significance of carbonate rocks in the Middle Mesoproterozoic Yangzhuang Formation of northern margin of North China Craton

作　　者：杨晋东 赵峰华[1] 秦胜飞[2] 邹雨 宋昌贵 孙宇翔 YANG Jin-dong;ZHAO Feng-hua;QIN Sheng-fei;ZOU Yu;SONG Chang-gui;SUN Yu-xiang(College of Geoscience and Surveying Engineering,China University of Geosciences(Beijing),Beijing 100083,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]中国石油勘探开发研究院,北京100083

出　　处：《天然气地球科学》2020年第2期268-281,共14页Natural Gas Geoscience

基　　金：国家重点研发计划专项(编号:2016YFC0601001)资助.

摘　　要：为探究燕山地区中元古界杨庄组碳酸盐岩物源及其构造沉积环境,采集研究区碳酸盐岩样品进行常微量元素(主要是稀土)地球化学测试,结合地质背景,通过地球化学分析得出如下结论:样品稀土含量(平均50.8×10-6)远高于纯白云岩(小于10×10-6),Al2O3与∑REE+Y呈显著正相关,且PAAS标准化稀土配分模式图呈平坦页岩型(除Eu的正异常),说明杨庄组碳酸盐岩受到显著陆源碎屑混染。杨庄组经历海侵海退旋回沉积,与Sr/Ba值和∑REE+Y值变化曲线相对应,暗示海平面升降控制陆源碎屑输入量;通过La/Sc-Th/Co、La/Yb-∑REE+Y和TiO2-Zr等关系图解和元素地球化学特征分析,结合华北克拉通北缘岩浆活动和构造演化,认为研究区的陆源碎屑最可能源于华北元古代大陆裂谷背景下形成的的酸性长英质火成岩类;杨庄组沉积相总体为潮上-潮间带,海水氧化性较强,不利于烃源岩的发育。In order to study its structural-sedimentary environment and provenance,we collected carbonate rocks in research area and used method of combining geochemical analysis and geological background. Conclusions are drawn as follows. The content of rare earth elements of Yangzhuang Formation outclasses that of pure dolomite and shows a remarkable correlativity between Al2O3 and ∑REE+Y,and REE+Y distribution pattern of PAAS is similar to shale(besides Eu positive anomaly),which indicate its depositional process was influenced by terrigenous clastic significantly. Yangzhuang Formation experienced marine transgression-regression cycle,and change curves of Sr/Ba and ∑REE+Y and their correlation show that sea level eustacy controls the content of terrigenous clastic. The relation diagrams of La/Sc-Th/Co,La-Th-Sc and TiO2-Zr and analysis of element geochemical characteristics combined with magmatism and tectonic evolution show that the terrigenous clastic of carbonate rocks in Yangzhuang Formation originated from acid-felsic igneous rocks under continental rift environment in Proterozoic. The sedimentary facies of the Yangzhuang Formation are supralittoral zone and inter tidal zone,and seawater has strong oxidability,which is not conducive to the source rock development.

关 键 词：杨庄组 碳酸盐岩 稀土元素 物源 

分 类 号：TE133.113[石油与天然气工程—油气勘探]