西秦岭徽成中-新生代红层盆地陇成段航磁构造成因探讨  

Huicheng Mesozoic-Cenozoic Red-Bed Basin in West Qinling Mountains Inferred from Aeromagnetic Measurements

作　　者：崔志强[1,2] 路宁 胥值礼[1,2] 高卫东 李磊[1,2] 西永在 郑红闪[1,2] CUI Zhiqiang;LU Ning;XU Zhili;GAO Weidong;LI Lei;XI Yongzai;ZHENG Hongshan(Institute of Geophysical and Geochemical Exploration,CAGS,Langfang,Hebei 065000;The National Center for Geological Exploration Technology,Langfang,Hebei 065000)

机构地区：[1]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000 [2]国家现代地质勘查工程技术研究中心,河北廊坊065000

出　　处：《地质与勘探》2024年第6期1196-1204,共9页Geology and Exploration

基　　金：中国地质调查局地质调查项目(编号:DD20230245)资助。

摘　　要：西秦岭徽成盆地分布着一套中-新生界陆相红色砂砾岩层,斜跨于秦岭造山带中部,其所处位置特殊、构造复杂。本文以该盆地文县-成县地区的高精度航磁数据为主,结合区域地质和物性等资料,对徽成红层盆地西南段(成县以西)的构造及其演化特征进行研究。区内航磁数据揭示了该盆地的磁性基底,清晰地展现了盆地及周缘的构造格架。与残留红层盆地轮廓基本一致的宽缓强磁异常是盆地下伏元古界强磁性变质基岩凸起所致,并向成县方向磁性变质基底逐渐变浅。盆地周缘扭折的勉略缝合构造带(文康段)、帚状的凤太断裂带(舟曲-成县)以及作为二者之间纽带的白龙江走滑断裂及其叠加的北东向次级断裂,揭示了该区域在早白垩世和新近纪经历了拉分-伸展成盆、挤压-走滑改造交替主导的两期盆山耦合。不同红层单元的伽玛能谱变化特征显示,该盆地东河群和甘肃群物源可能分别来源于盆地南、北两侧的燕山-印支期中酸性岩体和古生界。红层盆地的形成演化研究成果对整个秦岭造山带地质及构造演化研究具有重要的参考价值。The Huicheng Basin in West Qinling Mountains contains a set of Mesozoic Cenozoic terrestrial red sandstone layers.This basin spans the central part of the Qinling Orogenic Belt,and has a unique location and complex structures.This work focused on high-precision aeromagnetic data from the Wenxian-Chengxian area in this basin,and combined with regional geological and geophysical properties,to study the structural and evolutionary characteristics of the southwestern section of the Huicheng red-bed basin(west of Chengxian County).The aeromagnetic data reveals the magnetic basement of the basin,and clearly illuminates the structural framework of the basin and its periphery.The wide and gentle strong magnetic anomaly that is basically consistent with the outline of the residual red-bed basin was caused by the uplift of the underlying Proterozoic strong magnetic metamorphic bedrock in the basin,and the magnetic metamorphic basement gradually became shallower towards Chengxian County.The major fault structures include the Mianlue suture tectonic zone(Wenkang section),broom-like Fengtai fault zone(Zhouqu-Chengxian),and the in-between Bailongjiang strike slip fault,as well as the superimposed NE-trending secondary fault.These faults reveal that the basin has experienced two periods of basin-mountain coupling dominated by alternate pull apart extension and compression strike slip transformation in the Early Cretaceous and Neogene.And the Gamma spectrum variation characteristics of different red-bed units indicate that the provenance of the Donghe Group and Gansu Group may come from the Yanshan-Indosinian intermediate-acidic rock masses and Paleozoic strata on the south and north sides of the basin,respectively.The research results on the formation and evolution of red-bed basins have important reference value for the geological and structural evolution of the entire Qinling Orogenic Belt.

关 键 词：航空磁测 红层盆地 构造演化 中-新生界 徽县-成县 秦岭造山带 

分 类 号：P318.43[天文地球—固体地球物理学] P631[天文地球—地球物理学]