Seismic Recognition and Origin of Miocene Meishan Formation Contourite Deposits in the Southern Qiongdongnan Basin,Northern South China Sea  

作　　者：FENG Yangwei REN Yan LYU Chengfu ZHANG Peng CHEN Ying JIN Li 

机构地区：[1]School of Geographical Science and Tourism,Nanyang Normal University,Nanyang,Henan 473061,China [2]Shandong Key Laboratory of Depositional Mineralization&Sedimentary Mineral,Shandong University of Science and Technology,Qingdao,Shandong 266590,China [3]School of Earth Sciences,East China University of Technology,Nanchang 330013,China [4]PetroJindian(Beijing)Sci-Tech Co.,Ltd,Beijing 100000,China [5]Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China [6]CNOOC Research Institute Co.,Ltd.,Beijing 100028,China

出　　处：《Acta Geologica Sinica(English Edition)》2021年第1期131-141,共11页地质学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(grant no.41972155);the Jiangxi Provincial Natural Science Foundtion(grant no.2020BABL211019);the National Science and Technology Major Profect(grant no.2016ZX05026007)。

摘　　要：Research into the contourite deposits in the Upper Meishan Formation of the southern Qiongdongnan Basin in South China Sea is weak;their characteristics,distribution and original geological conditions are not clear.Using geologic al and geophysical methods including seismic and drilling data,based on seismic reflection characteristics,geometrical configuration description,and wave impedance inversion,two types of contourite deposits are recognized.Contourite deposits have blurred boundaries between each deposit and disordered internal seismic reflections;They are mound-shaped only in transverse section,and banded in the longitudinal direction.TypeⅠcontourite deposits are conical,with mediumhigh amplitude,low-continuity,low-frequency mound-shaped seismic facies,and subparallel-chaotic reflections internally.These deposits are conical with sharp tops,the canal between mounds is V-shaped and deep.The western wing is gentle and the eastern wing is steep,with the slope toe mostly between 10°and 20°,and width height ratio about 1-2.TypeⅡcontourite deposits are flat,exhibiting medium-amplitude,medium-continuity,low-frequency mound-shaped seismic facies,with subparallel weak reflections internally.Their mounds are flat with gently arced tops,with shallow canals between.The slope toe is between 5°and 10°,with a width height ratio of about 2-5.The wave impedance value of these contourite deposits is 4.6 kg/m^(3)×m/s to 6.8 kg/m^(3)×m/s,about 5.8 kg/m^(3)×m/s on average,which is presumed to represent marlycalcareous clastic sediments.The contourite deposits mainly develop beneath the slope break at the margin of the faultcontrolled platform in the Southern Uplift zone of the basin.In plane view,they are distributed approaching a west-to-east direction,and in section,lie in low-lying areas near the faults at fault-controlled terraces of the Southern Uplift zone,with a paleo-current direction nearly west-to-east.The paleotectonic setting of the gentle monoclinic platform was favorable for the development of such co

关 键 词：CONTOURITES seismic reflection characteristics MIOCENE Qiongdongnan basin South China 

分 类 号：P512.2[天文地球—地质学] P611