北衙金矿区构造应力场数值模拟

NUMERICAL SIMULATION FOR TECTONIC STRESS FIELD OF THE BEIYA GOLD DEPOSIT

在矿区地质背景研究的基础上,运用有限元原理采用线弹性模型,对北衙地区进行了三维构造应力场数值模拟。模拟结果表明,北衙向斜为一断陷盆地,向斜西翼存在隐伏断裂。在东西向挤压力作用下,在向斜两翼的应力拉张区内产生四条近南北向的断裂(组),为斑岩岩浆上侵以及金铅锌多金属矿的赋存提供了有利的构造部位。

Based on the study on the geological background of the Beiya gold deposit, with line elasticity model of finite element, the authors study the numerical simulation of 3D tectonic stress field in the Beiya mine area. The results show that the Beiya syncline is a depression basin. Under the EW compressional stress, the carbonate rock strata of the Beiya Group was transformed into a syncline; it transformed nonsymmetrically because there exist concealed faults on west limb of the syncline. There occur four regions of tensile stress on both limb of the syncline wings, the regions of tensile stress with a strip shape distribute symmetrically and parallelly, the respective range and the shape of tensile stress region are variable in plane and vertically. Finally, the regions of tensile stress trend to produce four N S fault groups under the action of the maximum principal stress in plane and the tensile stress in uprightness. These faults provide benificial tectonic positions for porphyry intrusion and Au Pb Zn ores formation. It shows that tectonic stress field controls the transformation field, and the driving forces controlled by tectonic stress field result in structural forming and magma activating and metallic elements depositing.