湘中地区中奥陶统烟溪组沉积相特征  

Sedimentary facies characteristics of Middle Ordovician Yanxi Formation in central Hunan Province

作　　者：陈广[1,2] 刘辰生 郭建华[1,2] 周瑶[1,2] 吴诗情 李智宇 CHEN Guang;LIU Chensheng;GUO Jianhua;ZHOU Yao;WU Shiqing;LI Zhiyu(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha 410083,China;School of Geosciences and Info-Physics,Central South University,Changsha 410083,China)

机构地区：[1]中南大学有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083 [2]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《断块油气田》2020年第5期561-566,共6页Fault-Block Oil & Gas Field

基　　金：湖南省自然科学基金项目“湘中和湘南地区下古生界原型盆地对细粒沉积控制作用”(2017JJ1034)。

摘　　要：通过分析岩性、沉积构造及岩心薄片观察等资料,在湘中地区烟溪组识别了4种沉积相类型,从盆地近源(NE侧)到盆地沉积中心(SW侧),依次为浊积扇相、浅海陆棚相、半深海相、深水盆地相。烟溪组沉积演化经历了4个阶段:SQ1上升半旋回快速海侵,发育浅海陆棚相、半深海相、深水盆地相;SQ1下降半旋回开始海退,区内半深海相和深水盆地相展布面积减小,浅海陆棚相面积增大,近物源的NE区开始发育浊积扇相,沉积相体系向SW迁移;SQ2上升半旋回海侵,海平面再次上升,沉积相体系与SQ1上升半旋回大体相似,但半深海相发育区域减小;SQ2下降半旋回快速海退,浊积扇相广泛发育,深水盆地相不再发育。By analysis of lithology,sedimentary structure and thin section,four types of sedimentary facies had been identified in the Yanxi Formation of central Hunan.From the near-source area(NE side)to the sedimentary center(SW side),turbidity-fan facies,neritic shelf facies,hemi-deep sea facies and deep-water basin facies were developed in turn.The sedimentary evolution of the Yanxi Formation can be divided into four stages.SQ1 ascending semi-cycle experienced rapid transgression,in which neritic shelf facies,hemi-deep sea facies and deep-water basin facies were developed.SQ1 descending semi-cycle began to experience regression,with the distribution area of the hemi-deep sea facies and deep-water basin facies decreased and the area of the neritic shelf facies increased;the turbidity-fan facies developed in the NE area near the source,and the sedimentary facies system migrated to the SW.SQ2 ascending semi-cycle experienced transgression with the sea level rose again,and the sedimentary facies system was similar to the SQ1,but the distribution area of hemi-deep sea facies reduced.SQ2 descending semi-cycle experienced rapid regression,with the turbidity-fan facies developed extensively and the deep-water basin facies no longer developed.

关 键 词：沉积旋回 沉积模式 中奥陶统烟溪组 湘中地区 

分 类 号：TE121.3[石油与天然气工程—油气勘探]