Numerical simulation of multi-stages tectonic evolution and ore-controlling mechanism of the typical metallogenic province of the South China fold system

作者:Yu, M (Yu Miao)[ 1 ] ; Liang, P (Liang Peng)[ 2 ] ; Chen, JP (Chen Jian-Ping)[ 3 ] ; Gong, JH (Gong Jian-Hua)[ 1 ] ; Li, HL (Li Hai-Long)[ 4 ] ; Wang, JC (Wang Ji-Chun)[ 3 ]

CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION

卷: 58  期: 12  页: 4534-4543

DOI: 10.6038/cjg20151216

出版年: DEC 2015

摘要

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 3D model, that is based on the geological tectonic evolution of the study area, were carried out on a fluid-solid coupling model in FLAC3D. 

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 multi-stages 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 fracture-rock 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 the Gejiu ore district and may be of significance for future exploration in the study area and analogous regions elsewhere. These research findings with space-time dual attributes not only verify the existing understanding of the metallogenic regulation, but also have clear implications for complementing knowledge on the evolution process of geologic structures, genetic relationship and internal mechanism.

通讯作者地址: Yu, M (通讯作者)

Chinese Acad Sci, Inst Remote Sensing & Digital Earth, State Key Lab Remote Sensing Sci, POB 9718, Beijing 100101, Peoples R China.

地址:

[ 1 ] Chinese Acad Sci, Inst Remote Sensing & Digital Earth, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China

[ 2 ] Chinese Acad Geol Sci, Inst Mineral Resources, Beijing 100037, Peoples R China

[ 3 ] China Univ Geosci, Beijing 100083, Peoples R China

[ 4 ] Chinese Acad Geol Sci, Inst Geomech, Beijing 100081, Peoples R China