Sedimentary Processes and Depositional Characteristics of Coarse-grained Subaqueous Fans along Steep Slopes in a Lacustrine Rift Basin:A Case Study from the Dongying Depression,Bohai Bay Basin,China  

作　　者：YANG Baoliang QIU Longwei YANG Yongqiang Kouassi Louis KRA DONG Daotao Danish KHAN 

机构地区：[1]School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China [2]Key Laboratory of Deep Oil and Gas in China University of Petroleum(East China),Qingdao,Shandong 266580,China [3]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 550081,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第2期526-547,共22页地质学报（英文版）

基　　金：supported by the National Science Foundation of China(Grant Nos.41972099,4217020246);the National Science and Technology Major of China(Grant Nos.2017ZX05009-002,2017ZX05072-002)。

摘　　要：Coarse-grained subaqueous fans are vital oil and gas exploration targets in the Bohai Bay basin,China.The insufficient understanding of their sedimentary processes,depositional patterns,and controlling factors restricts efficient exploration and development.Coarse-grained subaqueous fans in the Yong′an area,Dongying Depression,are investigated in this study.These fans include nearshore subaqueous fans,and sublacustrine fans,and their sedimentary processes,depositional patterns and distribution characteristics are mainly controlled by tectonic activity and paleogeomorphology.Nearshore subaqueous fans developed near the boundary fault during the early–middle deposition stage due to strong tectonic activity and large topographic subsidence.Early sublacustrine fans developed at the front of the nearshore subaqueous fans in the area where the topography changed from gentle to steep along the source direction.While the topography was gentle,sublacustrine fans did not develop.During the late weak tectonic activity stage,late sublacustrine fans developed with multiple stages superimposed.Frequent fault activity and related earthquakes steepened the basin margin,and the boundary fault slopes were 25.9°–34°.During the early–middle deposition stage,hyperpycnal flows triggered by outburst floods developed.During the late deposition stage,with weak tectonic activity,seasonal floods triggered hyperpycnal flows,and hybrid event beds developed distally.

关 键 词：sedimentary processes depositional characteristics paleogeomorphology coarse-grained subaqueous fan lacustrine rift basin Dongying Depression 

分 类 号：P618.13[天文地球—矿床学]