龙门山山前带中段分层差异变形特征及成因  

Analysis of stratified deformation difference in piedmont zone of the middle Longmen Mountain

作　　者：郑娜 何登发[1] 汪仁富 孟宪武[2] 王莹[2] Zheng Na;He Dengfa;Wang Renfu;Meng Xianwu;Wang Ying(School of Energy Resource,China University of Geosciences(Beijing),Beijing 100083;SINOPEC Southwest Oil and Gas Company,Chengdu 610031)

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国石化西南油气分公司,成都610031

出　　处：《地质科学》2024年第3期768-780,共13页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金重点项目“上扬子克拉通盆地深层新元古代裂谷体系的结构、成因及其控油气作用”(编号:42330810);国家自然科学基金企业创新发展联合基金项目“海相深层油气富集机理与关键工程技术基础研究”(编号:U19B6003⁃01)资助。

摘　　要：龙门山构造带是研究陆内构造变形活动的理想场所之一。龙门山山前带的构造变形整体具有纵向分段、横向分带、垂向分层的特点。为了明确龙门山山前带中段分层变形特征,并进一步探讨分层差异变形成因。本文应用浅表地质露头、数字高程与三维地震数据等资料,开展龙门山山前带中段构造样式的识别及分层差异解析,绘制典型剖面构造演化图,计算关键层位缩短量。研究表明:龙门山山前带发育多种类型的断层相关褶皱,其中,上三叠统叠瓦逆冲构造以及深部逆冲楔在龙门山山前带中段广泛发育。总体来看,龙门山山前带中段大致以嘉陵江组为界,呈叠瓦逆冲构造系统与深部中小尺度冲断构造系统垂向叠置的构造特征,滑脱层对分层变形起着控制作用。此外,岩性也影响着分层变形,嘉陵江组膏盐岩等区域性分布的软弱层在变形中发挥着传递应变的滑脱层作用;多期次变形的叠加也是导致龙门山山前带中段分层差异变形的重要原因。Longmen Mountain tectonic belt is one of the ideal places to study intracontinental tectonic deformation activities.The tectonic deformation of Longmen Mountain piedmont belt is characterized by longitudinal segmentation,transverse zonation and vertical stratification.In order to clarify the characteristics of stratified deformation in the middle of the piedmont zone of Longmen Mountain,and further discuss the causes of stratified differential deformation.In this paper,the surface geological outcrop,digital elevation and 3D seismic data are used to identify the structural styles and analyze the stratification differences in the middle section of the piedmont zone of Longmen Mountain.The key horizon tectonic maps and typical section tectonic evolution maps are drawn and the shortening is calculated.The results show that there are many types of fault-related folds in the fore-belt of Longmen Mountain,among which the Upper Triassic imbricated thrust structures and deep thrust wedge are widely developed in the middle of the fore-belt.The middle section of the Longmen Mountain fore-belt is roughly bounded by the Jialingjiang Formation,which is characterized by vertical superposition of imbricated thrust system and deep medium and small scale thrust system,and the detachment layer controls the stratified deformation.In addition,the lithology also affects the stratified deformation,and the regional weak layers such as the salt rock of Jialingjiang Formation play the role of the detachment layer of strain transfer during deformation.The superposition of multi-stage deformation is also an important reason for the stratification differential deformation in the middle of piedmont zone of Longmen Mountain.

关 键 词：龙门山 山前带 构造样式 分层变形 多重滑脱 

分 类 号：P542[天文地球—构造地质学]