冲绳海槽西部陆坡第四纪沉积地层划分  

Quaternary Stratigraphic Division in the Western Slope of Okinawa Trough

作　　者：董刚[1,2] 蔡峰 闫桂京[1,2] 李清 梁杰[1,2] 孙运宝 骆迪[1,2] 李昂 DONG Gang;CAI Feng;YAN Guijing;LI Qing;LIANG Jie;SUN Yunbao;LUO Di;LI Ang(MLR Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Qingdao Institute of Marine Geology,CGS,Qingdao,Shandong,266071;Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong,266071)

机构地区：[1]国土资源部海洋油气资源与环境地质重点实验室,中国地质调查局青岛海洋地质研究所,山东青岛266071 [2]青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266071

出　　处：《地质学报》2018年第12期2550-2560,共11页Acta Geologica Sinica

基　　金：国土资源部海洋油气资源与环境地质重点实验室基金项目(编号:MRE201407);国家自然科学基金青年基金项目(编号:41702162);山东省自然科学基金博士基金项目(编号:ZR2017BD034)联合资助成果.

摘　　要：冲绳海槽西部陆坡是认识深海斜坡沉积的重要区域。通过对高分辨率地震资料的精细解释,结合已有的研究成果,在冲绳海槽西部陆坡海底以下识别出4个主要的地震层序界面,相应地划分出四个主要地震层序,各层序分别对应全新世沉积层(Q4)、晚更新世沉积层(Q3)、中更新世沉积层(Q2)和早更新世沉积层(Q1)。从陆坡上部往下由斜交前积反射结构过渡到杂乱的反射结构,在地震剖面上可识别出杂乱的丘形反射单元,是滑塌体和重力流沉积的典型地震反射特征,反映出一种高能的、极不稳定的沉积环境。海槽轴部以平行-亚平行的地震反射特征为主,显示了稳定的深海-半深海的沉积环境。地震反射结构的多样性反映了冲绳海槽西部陆坡沉积环境的复杂性和沉机作用类型的多样性,沉积地层结构是多种因素共同作用的结果。东海陆架和冲绳海槽发育相同的第四纪地层垂向序列,同时冲绳海槽西部陆坡与东海陆架第四纪沉积层在层序界面、沉积层厚度、变形程度和产状等方面存在着差异,单靠地震资料来进行两个地区的地层对比存在着不确定性。The western slope of Okinawa trough is an important area for understanding the deep- sea slope deposition. Combined with the existing research results, four seismic sequence boundaries below the sea floor in the west slope of the Okinawa trough have been identified using the detailed interpretation of high resolution seismic data, and accordingly, four main seismic sequences were divided as follows the Holocene sediments (Q4), late Pleistocene sediments (Q3), Middle Pleistocene sediments (Q2) and early Pleistocene sediments (Q1). From the upper slope down, seismic facies transits from the oblique progradational reflection configuration transits to chaotic seismic reflection configuration, and mixed mound seismic reflection units identified in the seismic section are the typical seismic reflection characteristics of landslides and gravity flow deposits, reflecting a high- energy and very unstable sedimentary environment. The axis of the trough is mainly characterized by parallel- subparallel seismic reflection, which shows the stable sedimentary environment of the deep sea and bathyal. The diversity of the seismic reflection structures reflects the complexity of the sedimentary environment and the diversity of sedimentation types on the west slope of the Okinawa trough. The sedimentary stratigraphic structure is affected by many factors. The East China Sea shelf and Okinawa trough have the same vertical Quaternary stratigraphic sequences. But the Quaternary sediments between the western slope of Okinawa trough and the East China Sea shelf have some differences in the sequence boundary, sediments thickness, deformation and occurrence of the sedimentary sequence. Therefore, uncertainties occur in the stratigraphic correlation between two regions using seismic data only.

关 键 词：冲绳海槽 第四系 西部陆坡 地震资料 地层划分 

分 类 号：P736.21[天文地球—海洋地质]