胶东胶北地体与北苏鲁造山带深部结构特征——来自地球物理深部探测的启示  

Deep structural features of the Jiaobei terrane of Jiaodong and the North Sulu orogenic belt:the inspiration from deep exploration of the geophysics

作　　者：贺春艳 姚铮 郭国强 刘洪波 宋明春 李世勇 陈大磊 刘伟 HE ChunYan;YAO Zheng;GUO GuoQiang;LIU HongBo;SONG MingChun;LI ShiYong;CHEN DaLei;LIU Wei(Shandong Institute of Geophysical and Geochemical Exploration,Jinan 250013,China;No.6 Institute of Geology and Mineral Resources Exploration of Shandong Province,Weihai 264269,China)

机构地区：[1]山东省物化探勘查院,济南250013 [2]山东省第六地质矿产勘查院,威海264269

出　　处：《地球物理学进展》2022年第4期1392-1404,共13页Progress in Geophysics

基　　金：国家自然科学基金项目-山东联合基金“胶东深部金矿断裂控矿机理”(U2006201);山东省科学技术厅重大创新工程项目“深部探测综合地球物理技术”(2018CXGC1601);山东省地矿局矿产勘查项目“胶东金矿集区三维地质建模及深部探测示范”(KC2018009);地质勘查与科技创新项目“胶东深部金矿断裂综合地球物理研究”(KY202112)联合资助。

摘　　要：中生代晚三叠世形成的近EW走向的大别—苏鲁造山带,在郯庐断裂带左旋走滑作用下,其东段向北推至胶东胶北地体东侧的青岛—威海一带,整体呈NNE走向,本文利用重力、MT等方法对二者深部结构进行了相关研究:发现五莲—青岛断裂带与一条中-高重力异常带存在密切的耦合关系,基于速度结构约束的重力反演表明,在该断裂带附近,超高压变质地体携带条带状基性-超基性变质岩斜插入北侧胶北地体之下,因此保留了造山带俯冲、折返的构造形迹;蓬莱—荣成地区,在造山带中部发育显著的重力低异常,重力反演表明,该段主要展现了造山带垮塌后的岩浆活动形迹;基于重磁反演和MT测量获取的电性结构成像,发现招平断裂与上盘次级断裂共同形成一条大型“铲式”伸展-拆离构造带,胶莱盆地与胶北隆起结合部发育大型盆底及盆缘构造带,二者在深部相向而倾,形成一低阻-高导通道.The dabie-sulu Orogenic belt formed in the late triassic of the Mesozoic was pushed northward to the Qingdao-Weihai area on the east side of the Jiaobei terrane of Jiaodong by the left-lateral strike-slip of the Tanlu fault zone. The whole of the dabie-sulu Orogenic belt shows a NNE trend. In this paper,the gravity and MT methods are used to study the deep structure of the two structures. It is found that the Wulian-Qingdao fault zone is closely coupled to a middle-high gravity anomaly zone,and the gravity inversion based on velocity structure constraints shows that near the fault zone,the ultrahigh-pressure metamorphic terrane with strip-like basicultrabasic metamorphic rocks sloped under the North Jiaobei terrane and preserved the tectonic trace of the subduction and exhumation of the Orogenic belt. In the central part of the Orogenic belt in the Penglai-Rongcheng area,there is a significant low gravity anomaly,which mainly shows the magmatic activity after the collapse of the Orogenic belt. Based on the gravity-magnetic Inversion and the electrical structure imaging obtained by and MT measurements,it is found that the Zhaoping Fault and the secondary faults of its upper wall form a large-scale“Shovel-type”extension-detachment structural belt,in the joint of Jiaolai basin and Jiaobei uplift,there are some large basin bottom and basin margin structural belts,which are inclined to each other in the deep part and form a channel with low resistance and high conductivity.

关 键 词：苏鲁造山带 陆陆碰撞 俯冲 重力异常 速度结构 

分 类 号：P541[天文地球—构造地质学]