望儿山金矿床剪切带控矿作用的数学模型与模拟

MATHEMATICAL MODEL AND NUMERICAL SIMULATION OF SHEAR_ZONE METALLOGENESIS IN WANGERSHAN GOLD DEPOSIT

采用有限单元法对成矿期的应力场状态进行模拟，结果表明：构造应力场不仅控制了矿体的形成，而且也控制了矿化类型．高应变能高变化梯度的扩容区，利于石英脉型矿体的形成；而高应变能低变化梯度的扩容区，利于蚀变岩型矿体的形成．高应变能的收缩区类似于“泵”，在泵吸作用的影响下使矿液从“泵”体流向高应变能的扩容区．矿液的流向最终是受渗流势控制，由高值区向低值区流动．

The mathematical model is established in this paper for the shear_zone metallogenesis in Wangershan gold deposit. The finite element method is adopted for the simulation of the stress field in the metallogenic period. The results show that the tectonic stress field not only controls the formation of the ore body, but also controls the type of the mineralization. The dilatancy belt with high strain energy and highly fluctuating gradients is always filled with the gold_bearing quartz veins, while the dilatancy belt with high strain energy and low fluctuating gradients is always metasomatized, favorable for the formation of gold_bearing altered rock orebody. The contraction belt with high strain energy is similar to a “pump” causing the hydrothermal ore_forming solution to flow from the “pump” to the dilatancy belt with high strain energy. The ore_forming solution, finally controlled by the seepage potential, flows from a higher potential area to a lower one.