构造成矿非线性动力学:1.递增应力流变学模型

NONLINEAR DYNAMICS OF TECTONIC MINERALIZATION: 1. AN INCREMENTAL STRESS RHEOLOGY MODEL

本文提出了构造成矿作用动力学研究的递增应力流变学方法。利用该方法将构造变形、应力、流体流动、地球化学反应及成岩成矿作用等多过程耦合起来，可以从多种地质过程的耦合与反馈作用对构造成矿的动力学演化过程进行１～３维数值模拟。模拟的主要内容是在各种过程耦合作用下，以下描述构造成矿体系的主要变量的时空演化：（１）与成矿流体的形成和性质有关的变量，如地层中矿物（包括成矿物质）的溶解速率、流体中各组分的浓度与饱和度、流体温度、压力、离子强度等；（２）与构造变形和流体运移有关的各变量，如应力与变形速率、岩石孔隙度、构造（断裂）渗透率等；（３）与沉淀成矿有关的变量，如矿物（金瞩矿物和脉石矿物）的成核速率、各矿物的沉淀量等；（４）上述各有关变量间的时空耦合关系，如断裂渗透率时空演化与流体流动、汇聚和成矿的耦合关系等。

An incremental stress rheology model is developed to study the dynamics of tee-tonic mineralization. Much geological processes such as structural deformation, stress, fluid flow ,geochemical reaction and diagenesis and mineralization can be coupled through this approach ,so that we can simulate the dynamic evolution processes of tectonic mineralization in 1 to 3 dimensions under coupling and feedback of various processes. Main content in simulation is the spatio-temporal evolution of the set of descriptive variables characterizing tectonic mineralization state under coupling of various processes as following:(1) variables related to forming and property of ore-forming fluid ,such as dissolution rate of minerals(include metal minerals) in rock, concentration and saturation of aqueous species in fluid, temperature, pressure ,and ionic strength etc. ;(2) variables related to structural deformation and fluid flow, such as stress, deformation rate,fracture network,porosity,fracture permeability;(3) variables related to precipitation and mineralization, such as nucleation rate of gangue and metal minerals, accumulation precipitation of various minerals, etc. ;(4) spatio-temporal coupling relation of various variables above, such as the coupling relationship between spatio-temporal evolution of fracture permeability and flow and focus of fluid and ore-forming.