宁芜盆地深部地壳结构和岩浆侵入体形态特征及其对成矿的启示

Crustal structure and shape of deep magma intrusion,and their implications for mineralization in Ningwu Basin

在宁芜火山岩盆地部署了三条深反射地震剖面,通过精细的数据采集和处理,最终获得了高质量且可靠的深反射地震和初至波层析反演速度剖面。依据对反射结构和速度特征的分析,获得了以下认识:(1)利用层析反演速度成果刻画了岩浆侵入体在宁芜盆地深部空间的大体形态和分布范围;(2)依据深反射地震剖面反射同相轴和莫霍面结构特征,大体确定了深部岩浆侵入通道路径;(3)宁芜火山岩盆地下部地壳在6.0s上下位置发生解耦,在盆地正下方形成了地壳级别的鳄鱼嘴构造,控制着宁芜火山岩盆地深部的岩浆和构造活动;(4)阐明了宁芜火山岩盆地深部地壳结构和变形特征。这些成果的发现对探讨宁芜火山岩盆地深部成矿和动力学过程研究具有重要意义。

Three deep seismic reflection profiles were deployed in Ningwu volcanic basin. Migration and velocity profiles in high quality were gained by fine data seismic processing and tomography inversion. On the basis of the analysis to the reflection structure and of the velocity characteristics, we obtained the following results： （1） the shape and scope distribution of igneous intrusion body is depicted in terms of the profile of tomography inversion in Ningwu volcanic basin; （2） on the basis of deep seismic reflection migration profile, we analysed the characteristic of crust and Moho structure, and finally discovered the channel and the way how the magma go up from the deep crust; （3） in the deep seimic reflection profile, a crust-level crocodile structure was found beneath the Ningwu volcanic basin, which was caused by the crust decoupling in the range of 6.0 s. this .structure controlled the activity of magma and tectonics, （4） we expounded the earth＇s crust structure and deformation feature of the area. Those findings are of great significance to understanding and exploring the mineralization and dynamical processes of Ningwu volcanic basin.