现代黄河三角洲YRD-1401孔MIS 5以来沉积层序及其古环境意义  

The sedimentary succession of core YRD-1401 in the modern Yellow River Delta since MIS 5 and its paleoenvironmental significance

作　　者：钱胜玲 刘健[2] 王培培 张欣 王飞飞 安郁辉 QIAN Shengling;LIU Jian;WANG Peipei;ZHANG Xin;WANG Feifei;AN Yuhui(College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,Shandong;Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266071,Shandong;Central South Geological Survey Institute of China Metallurgical Geology Bureau,Wuhan 430083,Hubei;Faculty of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,Hubei;Chinese Academy of Geological Science,Beijing 100032;College of Marine Geosciences,Ocean University of China,Qingdao 266100,Shandong)

机构地区：[1]山东科技大学机构地球科学与工程学院,山东青岛266590 [2]中国地质调查局机构青岛海洋地质研究所,山东青岛266071 [3]中国冶金地质总局中南地质调查院,湖北武汉430083 [4]中国地质大学(武汉)地球科学学院,湖北武汉430074 [5]中国地质科学院机构,北京100083 [6]中国海洋大学海洋地球科学学院,山东青岛266100

出　　处：《第四纪研究》2021年第5期1317-1331,共15页Quaternary Sciences

基　　金：国家自然科学基金重点项目(批准号:41330964);山东省博士后创新项目(批准号:201903051)共同资助。

摘　　要：近年来渤海地区晚更新世以来沉积环境演化和地层划分存在争议。本文对现代黄河三角洲东南海岸带YRD-1401孔岩芯(长81.00 m)沉积物进行综合研究,旨在建立该孔晚更新世以来地层的沉积相序列和时间标尺,为解决地层划分争议提供新的证据。根据AMS 14C和光释光测年结果,并考虑到YRD-1401孔底部地层光释光年代的不精确性,本文主要研究YRD-1401孔MIS 5以来的沉积演化史。综合分析YRD-1401孔沉积地层的岩性特征和底栖有孔虫组合变化,结合测年结果,该孔可划分为6个沉积单元(从下往上DU 6~DU 1):最底部的DU 6(51.35~81.00 m)为受潮流影响的河流沉积(其形成时间有待进一步研究),DU 5(37.64~51.35 m)为MIS 5潮坪-近岸浅海沉积,DU 4(30.71~37.64 m)为MIS 3早期的潮坪沉积,DU 3(23.50~30.71 m)为MIS 3晚期至全新世早期形成的河流沉积,DU 2(14.22~23.50 m)为全新世早期(约10 cal.ka B.P.)至1855年形成的滨岸沼泽-滨岸浅水-近岸浅海~前三角洲沉积-海洋改造层,DU 1(0~14.22 m)为1855年以来发育的现代黄河三角洲沉积。晚更新世以来该孔有3个海相层(自下而上分别是DU 5、DU 4和DU 2),分别形成于MIS 5、MIS 3早期和全新世,表明晚更新世以来全球海平面变化是其主要控制因素。研究区MIS 4的沉积地层出现缺失。渤海沿岸地区多个钻孔地层的对比表明,区域性的差异构造沉降、沉积物供给和地层完整性等因素也是影响研究区晚更新世以来沉积地层发育的重要因素。Dramatical changes in sea level and the associated sea-land interactions are known to have occurred in the Bohai Sea during the Quaternary.There has been a debate on the ages of the latest three marine strata in the Bohai Sea during the Late Quaternary.Although the recent development in Optical Stimulated Luminescence(OSL)dating has led to great improvement in the precision of chronology,the environmental evolutions and division of sedimentary strata in the Bohai Sea have been open to debate since the Late Pleistocene.In this study,the sedimentary succession and chronological framework of core YRD-1401 were established based on the analyses of sediment grain size,benthic foraminiferal assemblages,accelerator mass spectrometry(AMS)14C and OSL datings,with a view to offering new insights into the division of sedimentary strata.Core YRD-1401(37°42'8.38″N,118°58'28.93″E;2.64 m elevation;81.00 m length;average recovery>75%)was retrieved from the modern Yellow River delta in 2014.In the laboratory,the core was split in half for photography,description and sampling,and 575 sediment grain-size samples and 326 benthic foraminifera samples were collected with an interval of 10~20 cm.In addition,8 samples were dated by AMS 14C and 14 samples were dated by OSL.Considering that the ages of the strata at the bottom of the core are far beyond the limit of OSL dating,this study tries to decipher the sedimentary history since MIS 5.On the basis of lithological and chronological characteristics,combined with downcore distributions of benthic foraminiferal assemblages,the sedimentary succession in core YRD-1401 can be divided into six depositional units,designated DU 6~1 in ascending order.DU 6(51.35~81.00 m)was deposited in a tidal-river environment,and the ages of DU 6 were beyond the quartz OSL dating limit.DU 5(51.35~37.64 m)corresponds to tidal flat to nearshore shallow-sea environment,and was formed in MIS 5.DU 4(37.64~30.71 m)is dominated by tidal flat deposits,and was formed during the early MIS 3.DU 3(30.71~23.50 m)w

关 键 词：晚更新世 黄河三角洲 沉积层序 古环境 

分 类 号：P534.631[天文地球—第四纪地质学]