晚更新世以来南黄海中部进积体序列与古河流系统  

Progradational sediment:succession and paleo-channel system in the central South Yellow Sea since the Late Pleistocene

作　　者：陈晓辉 陆凯[1,2] 田振兴 温珍河 徐晓达 张勇 孔祥淮[1,2] CHEN Xiaohui;LU Kai;TIAN Zhenxing;WEN Zhenhe;XU Xiaoda;ZHANG Yong;KONG Xianghuai(Qingdao Institute of Marine Geology,CGS,Qingdao 266237,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China)

机构地区：[1]中国地质调查局青岛海洋地质研究所,青岛266237 [2]青岛海洋科学与技术试点国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266237

出　　处：《海洋地质与第四纪地质》2023年第4期85-96,共12页Marine Geology & Quaternary Geology

基　　金：中国地质调查局地质调查项目“1:25万锦西、日照和霞浦县等图幅海洋区域地质调查”(DD20160139),“1:25万东海重点海域海洋区域地质调查”(GZH201500203),“东部重点海域海洋区域地质调查”(DD20221710);国家海洋地质专项项目“全国陆域及海区地质图件更新与共享”(DD20190377)。

摘　　要：通过高分辨率浅地层剖面声学地层与钻孔沉积地层的综合对比分析,系统研究了晚更新世以来南黄海中部海域的层序地层序列及其对海平面变化的响应。研究显示,基于高分辨率浅地层剖面自老至新划分的6个声学地层单元(U5、U4、U3、U2、U1-2、U1-1)与钻孔划分的沉积地层单元密切相关。MIS4期与末次冰盛期低海面时期发育的2个层序界面(R4、R2),将研究区晚更新世以来的层序地层自下而上划分为3个层序(SQ3、SQ2、SQ1),并识别出3期进积体序列与2期古河流系统。MIS5期与MIS3期高海面及海平面下降期间的2期东向进积体序列主要包括高位体系域与强制海退体系域,对应浅海—滨海沉积,厚度分别由西部的24 m与40 m向东明显变薄,而全新世高海面以来向海的进积体序列主要对应高位体系域,与长江源的浅海相泥质沉积相关,最大厚度超过16 m。研究区MIS4期和末次冰盛期发育的2期古河流系统与低位体系域相对应,最大沉积厚度分别超过36 m与24 m,均与长江及黄河密切相关,影响范围延伸至黄海槽及其以东海域,尤其末次冰盛期最远可达济州岛附近海域。High-resolution seismic profiles and depositional stratigraphy of cores in the central South Yellow Sea(SYS)since the Late Pleistocene were analyzed.The sequence stratigraphy succession and its response to sea-level changes were studied.Results indicate that high-resolution seismic stratigraphy could be divided into six seismic units(U5,U4,U3,U2,U1-2,and U1-1 from early to late times),and they were closely related to depositional units of cores.Based on the two sequence boundaries R4 and R2,corresponding to sea-level lowstands of MIS4 and the Last Glacial Maximum(LGM)respectively,three distinct sequences(SQ3,SQ2,SQ1 from bottom to top)were identified.There are three stages of progradational sedimentation and two stages of paleo-channel systems.Two eastward progradational successions match the sea-level highstands after sea-level falls of MIS5 and MIS3,with thickness maxima 24 m and 40 m in the western part of the study area respectively;and they mainly consist of highstand systems tract(HST)and falling stage systems tract(FFST)(neritic and littoral facies),and obviously become thinner eastward.The seaward progradational succession since the sea-level highstand of the Holocene,with a maximum thickness of 24 m,is related to HST(mud sediment of neritic facies from the Yangtze River).The two stages of paleo-channel systems were dated to MIS4 and LGM,with the maxima thickness of 36 m and 24 m respectively,and they correspond to the lowstand systems tract that were closely associated with the Yellow River and Yangtze River in the past.The paleo-channel systems extended to the Yellow Sea trough and its eastern area could reach the Jeju Island(Korean Peninsula)coast in the past especially in the LGM.

关 键 词：进积体 古河道 层序地层 晚更新世以来 南黄海中部 

分 类 号：P736.21[天文地球—海洋地质]