摘要
本文基于流-固耦合模型对研究区主要控矿构造的发育演化过程和控矿机制进行数值模拟研究.根据研究区不同构造期次下形成的最大主应力、体积应变、剪切应变、岩层渗透率变化、孔隙压力以及流体流动样式等成矿地质环境的定量结果,分析个旧超大型成矿系统的构造-岩浆-流体要素的相互作用机制.模拟结果显示,在成矿期构造应力场作用下,在先存背斜构造部位形成了强烈的张应力环境,构成了一系列沿北北东走向的有利侵位通道和空间.岩浆反复侵位于此并产生巨大浮力作用,控制了背斜构造发育并形成了低压力、高渗透的扩容空间,促进矿液长效聚集成矿.另一方面,根据东西向断裂组的应力-应变状态及共轭剪切断裂成生发育情况,剖析了该组断裂的形成机制以及在成矿期的性质、运动状态及导矿容矿作用.
The Gejiu ore district in Yunnan Province,southwestern China,is a world-class super large tin-polymetallic ore-concentrated area.The aim of this study is to reveal quantitatively the process and mechanism of mineralizing fluids and controlling factors of the study area.The mathematical model,simulation model and boundary conditions were constructed according to the geological setting and experimental objectives.In the research three groups of numerical simulation experiments with various boundary conditions on a simplified regional-scale 3Dmodel,thatis based on the geological tectonic evolution of the study area,were carried out on a fluid-solid coupling model in FLAC3 D.On the basis of calculated quantitative results,including maximum principal stress,volume strain,shear strain,rock permeability,pore pressure and fluid flow pattern,under different geological conditions, we analyzed comparatively and attained more systematic and in-depth understanding of metallogenic geologic conditions in the metallogenic epoch,the development of multistages structural compounding and combination,and the ore-forming process.The simulation results show that high tensile stress values are concentrated upon the existing anticline zone and distributed along the NNE direction under horizontal tectonic stress at metallogenic epoch.This type of structure provided the favorable channel and space for magmatic emplacement.With the great buoyancy effect,a series of superimposed anticline zones with low pore pressure,high permeability and expansion space were formed and promoted the ore fluid long-term gathering and metallogenesis.In addition,according to the stress-strain of the E-W faults and the development of the conjugate shear fracture,we analyze the formation mechanism,property and state in metallogenic epoch and the formation of the fracturerock groove structure,and the ore conducting role of the faults.The results provide insights into the multi-stages composite structures which may have controlled localization of mineralization in
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第12期4534-4543,共10页
Chinese Journal of Geophysics
基金
国家“深部探测技术与实验研究”专项课题(SinoProbe-03-02)
国土资源部公益性行业科研专项(201011002)联合资助
关键词
构造演化
控矿机制
流固耦合
数值模拟
个旧矿区
Tectonic evolution
Ore-controlling mechanism
Fluid-solid coupled
Numerical simulation
Gejiu ore district
