渤海海峡BHS01孔沉积物磁性地层学研究  

Quaternary Magnetostratigraphy Record in Sediments from Borehole BHS01 in the Bohai Strait

作　　者：孙军[1,2,3] 杨慧良 何磊[1,2] 褚宏宪[1,2] 路月 李攀峰[1,2] 刘长春 祁江豪[1,2] 强小科 SUN Jun;YANG Huiliang;HE Lei;CHU Hongxian;LU Yue;LI Panfeng;LIU Changchun;QI Jianghao;QIANG Xiaoke(Qingdao Institute of Marine Geology,China Geological Survey,Qingdao,Shandong 266071,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266071,China;School of Ocean Sciences,China University of Geosciences,Beijing 100083,China;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an,Shaanxi 710075,China)

机构地区：[1]中国地质调查局青岛海洋地质研究所,山东青岛266071 [2]海洋矿产资源评价与探测技术功能实验室青岛海洋科学与技术试点国家实验室,山东青岛266071 [3]中国地质大学(北京)海洋学院,北京100083 [4]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安710075

出　　处：《现代地质》2019年第2期315-324,共10页Geoscience

基　　金：中国地质调查局项目(DD20191003;DD20189643;DD20160147;DD20190365);国家自然科学基金项目(41330964;41606083)

摘　　要：磁性地层学研究是建立渤海地区第四纪沉积序列地层年代框架的主要技术手段之一。通过对渤海海峡地区BHS01孔(孔深121.3 m)进行详细的磁性地层学研究,结果表明:BHS01孔岩心记录了布容(Brunhes)正极性时至松山(Matuyama)负极性时底部,包括贾拉米洛(Jaramillo)和奥尔都维(Olduvai)正极性亚时。早、中更新世界线即布容(Brunhes)正极性时/松山(Matuyama)负极性时界限(B/M)深度位于该钻孔的46.4 m处。根据沉积速率,推测钻孔底部121.3 m处的年龄约2.25 Ma。综合沉积物的岩性、磁性及沉积速率变化特征,将BHS01孔沉积物记录的区域沉积过程自下而上划分为3个阶段:阶段Ⅰ(2.25～1.46 Ma)以河流相沉积为主;阶段Ⅱ(1.46～0.78 Ma)为稳定的湖泊相沉积;阶段Ⅲ(0.78～0 Ma)发育海陆交互相沉积。这一研究为该钻孔提供了可靠的年代标尺,为渤海海峡及邻区第四纪地层的划分对比和沉积演化过程提供了新的依据。Magenetostratigraphy is an effective method to establish reliable geochronological framework,which is critical for reconstructing long-term history of climatic and environmental changes in the past.A detailed palaeomagenetism study on sediments from borehole BHS01(121.3 m) which is located in the Bohai Strait has been carried out.The results show that the core from the borehole consists of three normal magnetozones which can be correlated to Brunhes,Jaramillo,Olduvai.The basal age of the core is estimated at about 2.25 Ma by the extrapolation of the sedimentation rate in the Matuyama Chron.The Brunhes/Matuyama boundary was found at the core depth of 46.4 m.Thus,through the comprehensive analysis of lithologic,magnetic and sedimentary rate characteristics,we divide the evolutional process of BHS01 into three sedimentary phases: phaseⅠ(2.25 to 1.46 Ma) mainly develops in a fluvial sedimentation;phaseⅡ(1.46 to 0.78 Ma) is accompanied with a stable lacustrine sedimentation;and phaseⅢ(0.78 to 0 Ma) develops in a marine and terrestrial sedimentation.Our results provide a reliable chronological framework for the borehole,facilitating the stratigraphic division and evolutional process of the Quaternary in the Bohai Strait and its neighboring regions.

关 键 词：渤海海峡 BHS01孔 磁性地层学 第四纪 

分 类 号：P318.4[天文地球—固体地球物理学] P539.3[天文地球—地球物理学]