摘要
对垂直于宁南弧形构造带的一条大地电磁测深剖面数据的处理和反演解释,揭示了沿剖面的中祁连隆褶带、靖远—西吉坳陷、西华山—六盘山隆褶带、兴仁堡—海原坳陷、中卫—同心断陷、卫宁北山—罗山坳陷、鄂尔多斯西缘隆褶带及天环坳陷30km深度的电性结构特征及相互关系;推断出祁连山碰撞造山带存在自南西向北东的逆冲,鄂尔多斯西缘隆褶带从东向西依次叠置形成逆冲叠瓦式断裂构造格局。电性分布特征表明:宁南弧形构造带内壳内低阻层主要在北祁连碰撞造山带及兴仁堡—海原坳陷内呈不连续分布,祁连山造山带内的壳内高导层往北终止于兴仁堡—海原坳陷内;兴仁堡—海原坳陷内的壳内高导层往北东终止于鄂尔多斯西缘逆冲褶皱带,与鄂尔多斯西缘逆冲推覆体下的晚古生代、早中生代滑脱面相交汇,沿剖面方向宁南弧形构造带内的壳内低阻层总体表现为西南深北东浅的特征。
By processing,interpreting and inverting magnetotelluric sounding data of a profile in the main arc structure in Ningxia Province,we revealed the electric property structure of middle Qilian folded-uplift belt,Jingyuan Xiji depression belt,Xihuasha Liupanshan folded-uplift belt,Xingren Haiyuan depression belt,Zhongwei Tongxin rift zone,Weining Beishan Luoshan depression belt,west-Ordos folded-uplift belt and 30 km depth of the Tianhuan depression belt,and the relationships among them.It can be inferred that the Qilian collision orogenic belt is of a thrust imbricate fault structure pattern,which thrusted from SW to NEN and the long pleated band in the western margin of Ordos stacked in order from east to west.The results show that low-conductivity layer in the crust is mainly distributed discontinuously in north Qilian collision orogenic belt and Xingrenbao Haiyuan depression belt in the arc structure of Southern Ningxia,and the high conductivity layer of Qilian orogenic belt is ended in Xingrenbao Haiyuan depression belt.The high conductivity layer of Xingrenbao Haiyuan depression belt is ended in the west Ordos thrust fold belt and meet the decollement layer of Ordos overthrust nappe.All in all,the low resistance layer in the crust of Southern Ningxia arc-shaped structure belt shows the characteristics of the deep southwest and the low northeast.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2013年第4期332-339,共8页
Earth Science Frontiers
基金
宁夏回族自治区地质调查院项目“宁夏大地电磁测深剖面测量”(基[2010]02-22-290)
关键词
逆冲构造
大地电磁测深
盆山构造体系
宁南弧形构造带
thrust-belt
magnetotelluric sounding
basin-mountain structure
Southern Ningxia arc structure belt
