珠江口盆地阳江东凹新生代岩浆活动特征与期次

根据阳江东凹邻区的录井及岩矿等资料,通过对阳江东凹的地震反射、地层关系及地层厚度等特征的分析,系统划分阳江东凹新生代的岩浆岩体类型及期次,并探讨其岩浆活动与南海区域构造运动的耦合关系。研究表明,阳江东凹新生代岩浆岩体分为侵入岩体与火山岩体两种类型,前者主要分布在东部洼陷内,后者主要发育于南部洼陷边部及周缘隆起区;岩浆活动可划分为文昌期、恩平期及珠江-粤海期,并受区域构造运动制约。珠琼运动两幕裂陷控制文昌期、恩平期的岩浆侵入活动,而裂陷后期的白云运动和东沙运动则控制盆地NWW向的断裂活动,从而影响珠江-粤海期的火山喷发活动。

Characteristics and periods of Cenozoic magmatic activity in the eastern Yangjiang Sag,Pearl River Mouth Basin,China

Based on the previous data of logging,rocks and ores in the adjacent area of the eastern Yangjiang Sag,the genetic types and formation periods of Cenozoic magmatic rock mass in the eastern Yangjiang Sag are systematically classified and the coupling relationship between the magmatic activity and the regional tectonic movement in the South China Sea is discussed through the analysis of characteristics of seismic reflection,stratigraphic relationship and stratigraphic thickness.The results show that there are two different types of Cenozoic magmatic rock mass,the intrusive rock mass and volcanic rock mass.The former is mainly distributed in the eastern sag,while the latter is mainly developed in the edge and surrounding uplift area of the southern sag.Geochronology research shows that the magmatic activities in the area can be divided into Wenchang epoch,Enping epoch and Zhujiang-Yuehai epoch respectively,and they are related with the regional tectonic movements.The two episodes of the Zhuqiong movement controlled the magma intrusion in Wenchang and Enping periods,while the Baiyun movement and Dongsha movement in the later stage of the rifting controlled the NWW trending fault activity in the basin and thus affected the volcanic eruption activity in Zhujiang-Yuehai periods.