摘要
在对辽东湾滩海地区的海洋阵列大地电磁测深资料进行研究的基础上 ,结合地质、地震、重磁以及测井资料 ,利用二维有限元法对该区地质结构、构造特征进行了分析。结果表明郯庐断裂带对该区影响深远。郯庐断裂带北延部分在辽东湾地区有 4条大断裂 ,其中二界沟盖州滩断裂分割了该区古老的结晶基底 ,以东为鞍山群 ,以西为建平群 ;大洼海南断裂则控制了中上元古界的分布 ,中上元古界仅分布在该断裂西侧。郯庐断裂作为一整体又控制了中生界火山岩的分布 ,断裂西侧火山岩发育程度高于东侧。另外 ,利用电磁测深技术的勘探深度大这一优势 ,对该区进行了深部层圈结构的研究 ,幔内高导层的深度约为 6 0km ,是软流圈的反映 ,软流圈的起伏与该区的隆凹呈明显的镜相关系 ;壳内高导层的深度约为 2 0km ,是地壳在拉伸过程中形成的折离带的反映
Based on the study of oceanic array magnetotelluric sounding data and the data of geophysical survey and well log,the geological texture and structural property of the beach area in Liaodong Bay were analysed with 2-D finite element method.The results indicate that Tanlu fault zone caused considerable effect on the area.The fault zone has four big fractures in Liaodong Bay,the Ejiegou Jiezhoutan fracture among them cut deep into the crystal palaeobasement;another fracture,Dawa Nanhai fracture,controlled the distribution of the Middle and Upper Proterozoic.The Middle and Upper Proterozoic were confined within the two sides of the fracture.What's more,as a whole,Tanlu fault also controlled the distribution of Mesozoic volcanic rocks,the volcanic rocks on the west side of the fault developed well than that on the east side.Besides,the superiority of great depth of electromagnetic sounding was also used to probe the deep texture of the globe.The result suggests that the depth of high conductive layer of the mantle is about 60 km,and that the undulation of the asthenosphere show distinct mirror relation;the depth of intracrustal high conductive layer is about 20 km.This is the reflection of detachment zone formed in earth crustal extension.