大巴山弧形构造的成因——来自数值模拟的证据
Origin of the Dabashan Salient: Evidence from Numerical Modelling
王瑞瑞 1许志琴 2梁凤华2
作者信息
- 1. 中国矿业大学资源与地球科学学院,江苏徐州,221116;煤层气资源与成藏过程教育部重点实验室,中国矿业大学,江苏徐州,221116;大陆构造与动力学国家重点实验室,中国地质科学院地质研究所,北京,100037
- 2. 大陆构造与动力学国家重点实验室,中国地质科学院地质研究所,北京,100037
- 折叠
摘要
大巴山弧形构造位于秦岭造山带的南缘,以其醒目的弓形几何形态而获得广泛的关注.大巴山弧形构造的形成机制历来是研究的热点.前人提出了若干大巴山弧形构造的成因模式.然而,目前存在的模式无法很好地解释为什么大巴山构造带会形成一系列形态独特的构造.最近,一些学者的应力场反演的工作显示,大巴山地区具有放射状的最大水平主压应力场的分布.因此,本文运用数值模拟的方法模拟了大巴山地区的主造山期的应力场和位移场,并在笔者之前物理模拟工作的基础上对大巴山弧形构造的成因进行了探讨.模拟结果表明,大巴山地区印支-燕山主造山期的最大水平主应力轨迹受城口房县弧形断裂和前缘两侧隆起所控制.大巴山弧形构造足以早期伸展背景下形成的弧形断裂边界、前缘两侧隆起的砥柱作用和底部滑脱作用为主要控制因素而形成的.
Abstract
Dabashan salient,located in the southern margin of the Qinling orogenic belt,has attracted much attention by its remarkable bow-shaped geometry.The mechanics of the salient has long been discussed and several models have been proposed.However,these models can not account for the forming of a series of specific characteristics in the Dabashan structural belt.Recently,some researchers'works have revealed that the maximum horizental principal stress field is radial.Using the numerical modelling method,the displacement field and stress field during intra-continental orogeny are modelled in the article.And the formation mechanism of the Dabashan salient is discussed.The numerical modelling results show that the pre-existing salient-shaped boundary originated in extensional setting and a pair of indenters in the front control the trajectory of the maximum horizontal principal stress during intra-continental orogeny.Considering the background and previous analogue modelling results by the author,décollement is also considered to be a key role in the process.The Dabashan salient resulted mainly from pre-existing salientshaped boundary formed in extensional setting,a pair of indenters in the front and lower décollement.
关键词
数值模拟/大巴山/弧形/边界/砥柱/滑脱Key words
numerical modelling/Dabashan/salient/boundary/indenter/décollement引用本文复制引用
基金项目
中国地质调查局工作项目(1212011120161)
出版年
2013
国家科技期刊平台
NSTL
维普
万方数据