南昆嵩凹陷中新世以来三角洲地震响应与沉积充填演化  

Seismic Response and Sedimentary Filling Evolution of a Delta Since the Miocene in the South Kunsong Sag

作　　者：贺华瑞 栾锡武 龚梁轩 叶传红 闫恒 HE HuaRui;LUAN XiWu;GONG LiangXuan;YE ChuanHong;YAN Heng(College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;College of Marine Science and Technology,China University of Geosciences(Wuhan),Wuhan 430074,China;School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266000,China)

机构地区：[1]山东科技大学地球科学与工程学院,山东青岛266590 [2]中国地质大学(武汉)海洋学院,武汉430074 [3]中国石油大学(华东)地球科学与技术学院,山东青岛266000

出　　处：《沉积学报》2023年第5期1568-1582,共15页Acta Sedimentologica Sinica

基　　金：中国—东盟海上合作基金项目(12120100500017001);国家自然科学基金项目(92055211)。

摘　　要：南昆嵩凹陷位于万安盆地西部,新生代以来伴随万安断裂多期左旋—右旋走滑运动,凹陷地层展布呈现典型的下断上拗双层结构。研究综合运用沉积盆地分析、层序地层分析以及地震解释等方法,通过精细刻画地震相,分析南昆嵩凹陷中新世以来三角洲地震响应,重点厘清晚中新世以来陆架三角洲三种亚相平面展布特点。研究结果表明:早中新世—中中新世时期,南昆嵩凹陷物源主要来自纳土纳隆起,凹陷西部发育冲积扇,冲积扇远端发育辫状河三角洲;晚中新世时期,湄公河水系越过昆嵩隆起区,形成大量山间水系,逐渐影响南昆嵩凹陷的沉积作用,伴随海平面上升,研究区开始发育陆架三角洲,南昆嵩凹陷开始成为湄公河物源主要的沉积区;上新世—更新世时期,湄公河三角洲大规模发育,由西向东进积,三角洲前缘进入万安盆地中部地区,在万安盆地中西部地区形成陆架三角洲—陆坡沉积体系。The South Kunsong sag is located in the western Wan'an Basin.Since the Cenozoic,with the multi-stage left-lateral strike-slip movement of the Wan'an fault,the strata distribution of the sag presents a typical double-layer structure of lower faults and upper bends.This study comprehensively uses sedimentary basin analysis,sequence stratigraphic analysis,and seismic interpretation to analyze the seismic response of the delta since the Miocene by finely characterizing the seismic facies,focusing on three types of shelf deltas since the Late Miocene,including the distribution characteristics of subphases on the plane.The results show that:during the Early Miocene-Middle Mio⁃cene,the provenance of the South Kunsong Sag was derived primarily from the Natuna uplift;alluvial fans developed in the western portion of the sag,and braided river deltas developed at the far end of the alluvial fans.The Mekong River water system crossed the Kunsong uplift area,forming a large number of intermountain water systems,which gradually affected the deposition of the South Kunsong Sag.With the rise of sea level,the study area began to develop shelf deltas,and the South Kunsong Sag became the main sedimentary area of the Mekong River source.During the Pleistocene period,the Mekong delta developed on a large scale,prograding from west to east;the delta front en⁃tered the central area of the Wan'an Basin,and the delta and the shelf delta-slope depositional systems were formed in the central and western regions of the Wan'an Basin.

关 键 词：南昆嵩凹陷 南海 三角洲 沉积充填演化 

分 类 号：P512.2[天文地球—地质学]