渤海湾西晚更新世以来3期海侵与古河道研究  

Study on the three stages of transgression and paleochannel of western Bohai Bay since the Late Pleistocene

作　　者：鲁庆伟[1] 郭维[1] 石文学[1] 王西玉[1] 詹健[1] 贾超[1] LU Qingwei;GUO Wei;SHI Wenxue;WANG Xiyu;ZHAN Jian;JIA Chao(Geological Institute of North China Geological Exploration Bureau of Tianjin,Tianjin 300170,China)

机构地区：[1]天津华北地质勘查局地质研究所,天津300170

出　　处：《地质通报》2021年第4期480-490,共11页Geological Bulletin of China

基　　金：中国地质调查局项目《天津1∶5万静海(J50E007012)、唐官屯(J50E008012)幅区域地质调查》(编号:DD20160042-8)

摘　　要：通过对钻孔岩心详细的沉积特征、微体古生物、测年(AMS 14 C、OSL)等综合研究,表明研究区晚更新世以来受到区域性的3期海侵事件影响,多表现为边缘海滨海湖沼相沉积。同时,追踪了3期海侵最大影响边界:晚更新世早期最大海侵(第3海侵层)位于唐官屯-西长屯-梁头镇;晚期最大海侵(第2海侵层)位于大黄洼—三呼庄一带;全新世海侵(第1海侵层)使整个研究区受到影响,其最大影响边界需进一步开展向西追踪工作,前人资料显示可西至文安县。另外,晚更新世以来发育4期古河道,且影响和制约海侵层及影响范围。二者相互作用,形成晚更新世以来的海陆交互沉积地层格架和滨浅海冲海积平原。利用年代学及深海氧同位素MIS(Marine isotope stages)1、3、5阶段3期海侵层标志层位等,对4期古河道形成时代进行了限定。结果表明,自下而上的4期古河道形成于MIS 5、MIS 4、MIS 3晚期—早全新世早期、晚全新世。研究结果可为该区域晚更新世以来的古地理演变、陆海变迁及水工环地质调查提供重要的地学资料。The comprehensive studies of sedimentary characteristics,micropaleontology and dating(AMS 14 C,OSL)of boreholes indicate that western Bohai Bay has been affected by three stages of regional transgression events since the late Pleistocene,and its sediments is mostly characterized by marginal seashore lake marsh facies.At the same time,the boundaries of the greatest influence of three stages'transgression were traced,namely Tangguantun-XichangTun-Liangtou boundary representing the third and the largest transgression in the early period of the Late Pleistocene,Dahuangwa-Sanhuzhuang boundary representing the second transgression in the late period of the late Pleistocene,and the first transgression in Holocene affecting the entire research area.The maximum impact boundary of the first transgression needs to be further traced to the west,and the predecessors'data show that it can extend to Wenan County.Furthermore,four stages of paleochannels were developed since the late Pleistocene,and they affected and restricted the sea invasion layer and the influence scope.The interaction between transgression and paleochannel resulted in the formation of marine and continental intersedimentation framework and the offshore alluvial plain since the Late Pleistocene.The formation age of the four paleochannels was defined by the use of chronology,deep-sea oxygen isotope MIS(Marine isotope stages)and the marker beds of three stages'(1,3,and 5)transgression.It is shown that the four stages,paleochannels were formed(from bottom to up)in the Early Holocene and the Late Holocene.The above results can provide important geological data for the study of paleogeography,land and sea changes and hydrogeololgy-engineering-environmental geology in the region.

关 键 词：天津 渤海湾 晚更新世 海侵 古河道 

分 类 号：P531[天文地球—古生物学与地层学] P534.63[天文地球—地质学]