Computer simulation builds simulation model on the base of computer and models running state and changes procession of real system along with time. Computer simulation is an effective experimental technique using it creates a kind of computer experimentation environments for complex system, the capacity and long-term dynamic nature of system were comprehensive performed in the short time by the computer. With the development of techniques, the application of simulation is expanding, there appear so many simulation styles, many projects and scientific problems are resolved by simulation. Especially recent years, it resolved many geological difficulties. Therefore, computer simulation will become an important way to apply computer science to geology science.
Metallogenetic series is a series of ore deposits located in the same geological tectonics which have definite comparability in the mineralization time, ore-forming mechanism, some commonness in the cause of metallogenetic and geological conditions of controlling ore deposits, intrinsic relation in the output of the ore deposition and space distribution. The ore deposit distribution of metallogenetic series in the igneous region, as their kinds and the causes of forming, are various and complex. The different type ore deposits were formed in terms of different metallogenetic evolvement phases, different concrete metallogenetic location, different conditions of the tectonic and wall rock. In the igneous region in eastern Zhejiang province, metallogenetic series’ space banding has dual characteristics which are deposition genus banding and forming cause banding. Surrounding the core of the volcanic framework, depositions show high temperature, medium temperature, low temperature banding output from inner to outer and from deep to shallow. The cause type of ore-forming appears hydrothermal after magma type phase, porphyry, hydrothermal-pseudomorphic replacement type, volcanic sedimentary type and intergrade type sequence output.
Through detailed studying of metallogenetic geological background, controlling conditions of deposition and metallogenetic law, from fluid dynamics of ore-forming processes, author thinks the fundamental metallogenetic factor of metallogenetic series in the igneous region is heat-substance flowing and transporting in thermodynamic field in metallogenetic phase, heat-flow field’s dynamic temporal and spatial evolvement should be concrete embodiment of unification ore-forming processes. Magmatic intruding to the porous medium (wall rock)full bearing liquid arose the temperature gradient which induce quantity of heat conduct from magmatic to wall rock and magmatic become cooling, on the other hand, which induce density gradient in the liquid in the medium. The two action change the field of heat flow in the ore-forming system. Metallogenetic geological fluid diffuses and transports with the driving of heat power, sediments one after another in the right location and finally forms the metallogenetic series.
In the light of this idea, we apply computer simulation technique to simulate and modeling the field of the heat flow in the igneous region in eastern Zhejiang province. First of all, constitute the controlling equation sets in terms of the law of mass conservation, the law of energy conservation, and Darcy law. Then following the procedure of computer simulation, it is established the mathematical model and simulation model by coding programs. The third, the simulation experiment is conducted. Finally the simulation results are output with drawing flow line charts and temperature distribution charts by the figure function of the Matlab software.We suppose that the study areas are porous medium full bearing fluid, although there are respective porosities and permeability in different locations, the movement of fluid is seepage basically satisfying Darcy law. Math model was described by a set of equations (including conservation equation, movement equation, state equation). For conveniently dynamic analysis and numerical computing, the sets of equations were concluded with Boussinesq approximation and de-dimension. Finally a set of partial differential equation consists of an ellipse equation set and a parabolic equation set is obtained. Boundary condition and initial condition were constituted according to the peculiarity of study areas and real situation.
It is hard to solve the coupled partial deferential equations because there are no exact resolving methods at present time. We apply the finite differential method to discrete numerical value for mathematical model and boundary conditions, then deducted the computer simulation model. Based on the Matalb platform, the programs were coded with Matlab language. Finally the heat-flow fields in mineralization regions are represented with flow-line charts and temperature distribution charts. In order to verify the simulation model and study the effective of dynamic coefficients to simulation results, the simulation experiment is conducted with various values of permeability, porosity, and viscosity coefficient within reasonable values. The system of heat-flow field is reacted correspondingly to the experiments, and we can conclude that the quantitative model is acceptable and has reflected the real world of the heat-flow fields.
Considering real magnetic intrusions, we simulated three shapes of magnetic intrusions, and the results are same. Through computer simulation, we conclude that heat-flow field played an important role in meineralization of metallogenic series accruing and space evolution in igneous region in eastern Zhejiang province. The basic mechanism of the mineralization of metallogenic series was heat-flowing and circulating with attracting minerals from deep bottom, transporting them to somewhere then minerals were deposited.
The unique aspects of this paper are as follows:
1) A new idea and method regarding discovering mineralization mechanism for a group of ore deposits which are originally related each other has been proposed firstly in this paper. With the proposed method, the forming and distribution regulation of metallogenic series of ore deposits can be quantitatively revealed and described by computer simulation.
2) A quantitative model, a dynamic equation of heat-flow, has been established upon studying the mechanism of heat-flow and various factors of mineralization and analyzing the geological background, the ore-controlling factors, and the mineralization mechanism in igneous region in eastern Zhejiang Province. This model represents key controlling factors and relationship of independent ore deposits in the chain of metallogenic series. This study is significant for further establishing quantitative prediction model of metallogenic series and discovering buried ore deposits.
3) A set of programs of computer simulating heat-flow is developed with Matlab professional tool that can monitor the forming procedure of metallogenic series heat-flow fields.
Combining computer simulation techniques with quantitative study of metallogenic series firstly proposed in this paper that open up a new way and may eventually solve the problem of shortage of mineral resources in China.