Deformation model for the Tongling ore cluster region,east-central China
Deformation model for the Tongling ore cluster region,east-central China
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DOI：
10.1080/00206814.2010.496236
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发表时间：
2011-02
影响因子：
2.6
通讯作者：
Qingfei Wang;Jun Deng;Dinghua Huang;Changhao Xiao;Li‐Qiang Yang;Yanru Wang
中科院分区：
文献类型：
--
作者：
Qingfei Wang;Jun Deng;Dinghua Huang;Changhao Xiao;Li‐Qiang Yang;Yanru Wang
铜陵地区是一个重要的铜、金矿区，由一系列s型褶皱组成，具有不规则的边界。区域结构框架传统上被认为是同轴压缩的结果，其次是简单的剪切。通过分析褶皱几何形状和断层密度的空间分布，提出了一种新的变形模型。新发现了早期北西—东西挤压和后期北东—南西挤压两个构造阶段。早期，下扬子地块与华北地块碰撞产生的缩短主要作用于东南和西北边界；靠近区域边界的北东—西向背斜紧致等斜并发生倒转，北西—西向走滑断层密度高，其空间分布呈大盒维数。另外，两个应力边界的NW-SE压缩是非同轴和不对称的。在不规则边界的布置上，非同轴和非对称压缩导致了s褶皱的形成，并导致了该地区东北部和西南部之间明显的位移。后期，伊扎那吉板块在欧亚板块下俯冲的西南分量产生了微弱的NE-SW挤压作用，作用于东北边界，局部构造发生了较小程度的变形。靠近区域边界的高断层密度促进了相互连通的断裂系统的形成，有利于岩浆的迁移和侵位，也有利于与火成岩活动有关的矿床的发育。
The Tongling region, an important Cu + Au ore district, consists of a series of S-folds and is defined by an irregular set of boundaries. The regional structural framework was traditionally considered to be the result of coaxial compression, followed by simple shear. By analysing the spatial distribution of fold geometries and fault densities, we propose a new deformation model. Two tectonic stages, that is, early NW–SE compression, and later NE–SW compression, have been newly identified in this region. In the early stage, shortening produced by the collision between the Lower Yangtze block and the North China block mainly acted on the south-eastern and north-western boundaries; NE–SW-trending anticlines adjacent to the regional boundaries are tight to isoclinal and overturned, and the density of NW–SE-trending strike-slip faults is high as revealed by the large box dimensions of the spatial fault distribution. In addition, NW–SE compressions of the two stress boundaries are non-coaxial and asymmetric. With regard to the disposition of the irregular boundaries, non-coaxial and asymmetric compression led to the formation of S-folds and to obvious displacement between the north-eastern and south-western parts of the region. In the later stage, weak NE–SW compression, derived from the south-westward component of subduction of the Izanagi plate beneath the Eurasian plate, acted on the north-eastern boundary and redeformed the local structures to a minor extent. High fault density near the region boundaries promoted the formation of an interconnected fault system, which facilitated magma migration and emplacement, as well as the development of deposits genetically related to the igneous activity.