文档介绍：下扬子地区中生代构造应力场分析 The analysis of tectonic stress field of the Mesozoic in Lower Yangtze Region 作者姓名宫龙学位类型学历硕士学科、专业地质学、构造地质学研究方向断裂构造学导师及职称任升莲副教授 2013年4月下扬子地区中生代构造应力场分析摘要下扬子区是我国重要的火山岩矿集区,构造、岩浆活动频繁,自然地质条件复杂,众多学者对此进行了详细的研究,但依然有很多现象得不到很好的解释。本文主要以下扬子区的脆性变形特征为研究对象,在野外调查基础上,对研究区的节理和断层进行了系统的研究,结合区域构造分析,获得本区中新生代的4期构造应力场序列并分析了区域内构造应力场的演化特征及动力学机制。构造应力场序列从早到晚依次为印支期NE-SW向构造挤压,燕山早期近S-N 向构造挤压,燕山晚期近E-W向伸展,早喜山期近E-W向构造挤压。借助GIS技术,建立了下扬子地区地质数据库,并开发了地质数据库软件, 用于野外数据采集和室内基础数据综合处理,并开发了基于GIS和Ansys自动建立地质模型和数学模型等软件工具。通过研究区的构造几何学与运动学特征以及构造演化史的分析,对下扬子地区中生代晚印支-早燕山期构造应力场进行数值模拟和分析,并与该地区地质构造现象进行对比研究,探讨下扬子地区地质构造的空间展布特征。模拟结果表明:最大主应力高值区分布在大别山东南突出体顶端(角)和大别山东北侧的郯庐断裂带上,最大主应力次高值区多分布在断裂带两侧,且呈现强弱相间规律性,次高值区的展布方向与长江中下游褶皱轴的展布方向相吻合;长江中下游串珠状火山断陷盆地与最大主压应力等值线云图次高值区分布相一致。剪应力高值区分布在断层处或产状变化处,如郯庐断裂带、龟山-梅山断裂带、五莲断裂和江绍断裂带产状变化处、江南断裂带产状变化处。位移场特征表明早燕山期下扬子地块有由南北两翼向中东部和中西部运动的趋势,最大位移速率为 mm/a, mm/a。关键词:下扬子区;中生代;构造应力场;有限元模拟;GIS;快速自动建模 The analysis of tectonic stress field of the Mesozoic in Lower Yangtze Region ABSTRACT The lower Yangtze region is an important volcanic rock ore concentration area of our country,with frequent tectonic and magmatic activity and complicated geological condition. Many academics conducted a detailed study on this, but there are still many phenomena not very well explained. This article following studies the brittle deformation of the lower Yangtze region, based on field survey, the joints and faults in the study area were systematically studied, with regional structural analysis, the sequence of 4 issues of the meso-Cenozoic tectonic stress field was acquired and regional characteristics of tectonic stress field evolution and dynamic mechanism was analyzed. Sequence of tectonic stress field, in turn, from early to late, is Indosinian Stage NE -SW to tectonic extrusion, the early Yanshan nearly S-N to tectonic extrusion, late Yanshan about E -W to extend, and about E -W to early Himalayan pression. By use of