东海陆架盆地中生界识别及其分布特征

Mesozoic recognition of East China Sea shelf basin and its distribution characteristics

根据近几年新采集、处理的地震剖面,主要从构造特征、地震反射特征、接触关系和地震层速度等4个方面对东海陆架盆地进行了中生界的识别。分析表明:中生界的断裂不发育,而火成岩较发育是区别于新生界的首要特征;中生界地震反射特征与新生界相比,其连续性变差、能量降低、频率降低;中生界与新生界的接触关系主要有2类:平行不整合接触关系和角度不整合接触关系;中生界与新生界的层速度差较大。研究区中生代地层分布广泛,厚度较大,具有南厚北薄的特征,呈北东、北北东向为主的东西分带的构造格局。

Based on newly acquired seismic data and seismic profiles after processing in recent years,Mesozoic recognition of East China Sea shelf basin was carried out,mainly from4 aspects,namely structural characteristics,seismic refection features,contact relationship and seismic formation velocity.The analysis results indicate the Mesozoic faults were undeveloped while the igneous rocks were well developed,which was the primary characteristic distinctive from that of in Cenozoic.Compared with Cenozoic seismic refection features,Mesozoic ones were less continuous,with low frequency and low energy.There were 2 types of contact relationship be-tween Mesozoic and Cenozoic,namely parallel unconformity and angular unconformity.The difference of seismic formation velocity between Mesozoic and Cenozoic was bigger and the stratums were distributed in south areas,with a wider distribution and bigger thickness,extending in direction of NE and NNE.