燕山地区京西坳陷青白口地区新元古界沉积相演化  

Sedimentary facies evolution of the Neoproterozoic in Qingbaikou area of Jingxi Depression,Yanshan region

作　　者：郭芪恒 金振奎[1] 朱小二 李硕 史书婷 王俊杰 程逸凡 Guo Qi-Heng;Jin Zhen-Kui;Zhu Xiao-Er;Li Shuo;Shi Shu-Ting;Wang Jun-Jie;Cheng Yi-Fan(College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)地球科学学院

出　　处：《古地理学报》2019年第3期422-430,共9页Journal of Palaeogeography：Chinese Edition

基　　金：国家重点基础研究发展规划“973”项目(编号:2006CB202300)资助~~

摘　　要：在充分调研前人研究成果的基础上,对京西坳陷青白口地区青白口系进行了野外实测、岩石薄片鉴定等研究,结合其岩性特征及沉积结构,细致划分了青白口系沉积相,建立了符合其沉积演化的沉积相模式。青白口系自下而上包括下马岭组、龙山组及景儿峪组,下马岭组为陆源碎屑浅海沉积体系,主要为较深水的陆棚相沉积,并且发育了砂质碎屑流;龙山组为陆源碎屑滨岸沉积体系,发育了大套的临滨及前滨砂体,主要受控于波浪和沿岸流的改造;景儿峪组为典型的碎屑岩碳酸盐岩混积潮坪,由于古纬度相对变化,沉积环境相对干旱局限且低能,下部和上部主要为紫红色泥岩沉积,中部发育大套厚层的碳酸盐岩。由龙山组陆源输入的碎屑物质沉积为主过渡到景儿峪组的内生清水碳酸盐岩沉积为主的环境,代表其构造条件和古地理环境逐渐趋于稳定。Based on full investigation of previous research,we carefully determined the types of the sedimentary facies of the Qingbaikou system in the Qingbaikou area,Jingxi Depression,and established its sedimentary facies model,by analysis of the field measured data,thin sections,as well as their lithologic characteristics and sedimentary structures.The Qingbaikou system consists of Xiamaling Formation,Longshan Formation and Jing eryu Formation from bottom to top.The results show that the Xiamaling Formation is mainly a set of relatively deep shelf deposits of the terrigenous clastic shallow-marine depositional system,and sandy debris flow deposits are first found;the Longshan Formation is a huge set of nearshore and foreshore sandy deposits of the terrigenous clastic shore depositional system,which is controlled by the modification of waves and longshore currents;and the Jing eryu Formation consists of a set of typically clastic-carbonate mixed tidal flat deposits,of which the upper and lower part are mainly composed of purple mudstones and the middle part is a huge set of thick carbonate,due to arid,restricted and low-energy environment related to the palaeolatitudinal variation.The clastic deposits,related to terrigenous inputs in Longshan Formation,turned into endogenous clear-water carbonate deposits in Jing eryu Formation,which suggests that the palaeogeographic environment gradually stabilized.

关 键 词：京西坳陷 新元古界 青白口系 下马岭组 龙山组 景儿峪组 沉积相 

分 类 号：P512.2[天文地球—地质学]