摘要
北康盆地陆坡区地震资料显示,自第四纪以来广泛发育深水块体搬运沉积,面积约占盆地面积50%以上。为了更加精细地了解该区块体搬运沉积的地震反射特征、分布期次、规模及其成因机制,共选取30条二维高分辨率地震剖面,采用精细解释的方法,对研究区内的块体搬运沉积体的外部形态和内部结构进行了识别和刻画;同时结合北康盆地地质背景和地震反射特征,讨论了自第四纪以来块体搬运沉积广泛发育的原因。结果表明,自第四纪以来,北康盆地共发育了6次大规模块体搬运沉积,识别出3种典型外部形态和6种内部结构单元;研究区第四纪块体搬运沉积体系的广泛发育主要由陆坡坡度、沉积速率、海平面变化及水合物分解和运移4个因素控制,其中海平面变化与水合物分解和运移起关键触发作用。
Through the analysis of seismic data of Beikang Basin,we found that since the Quaternary,deepwater MTD（mass transport deposits）has widely developed in the the slope area of the Beikang Basin,which covered the basin is more than 50%.In order to understand its seismic features,evolution period and scale and its triggering mechanism of MTD in Beikang Basin,this study selected 30 2-Dimensional high resolution seismic sections and used detailed analysis to identify and characterise its external morphology and internal structure.The study also combined the geological background in southern South China Sea and the analysis of seismic profile of MTD to discuss the causes of the extensive MTD since the Quaternary period.The results show that six large-scale of MTDs were found since the Quaternary in Beikang Basin and three typical external forms and six internal units were identified.The analysis suggests that the causes of the widely developed MTD in the study area are mainly composed of the depositional rate,the sea level change,the hydrate dissociation and migration and slope gradient.Among them,the sea level change and the hydrate dissociation and migration play a key role.
作者
何玉林
匡增桂
徐梦婕
He Yulin;Kuang Zenggui;Xu Mengjie(Guangzhou Marine Geological Survey,Guangzhou 510760,China)
出处
《地质科技情报》
CSCD
北大核心
2018年第4期258-268,共11页
Geological Science and Technology Information
基金
中国地质调查局项目(GZH2001100303
GZH201100305)
关键词
北康盆地
第四纪
块体搬运沉积
地震反射特征
形成机理
Beikang Basin
Quaternary
mass transport deposits
seismic characteristic
triggering mechanism
