斑岩矿床成矿金属大规模高效富集机制的动力学过程计算模拟

Numerical simulation and stochastical modelling have advantages on investigation of kinetic mechanism for geological processes and estimation of uncertainty for geological variables or/and events, respectively. Currently, there are two controversial perspectives of metallogenic mechanisms for the large-scale and efficient enrichment of metals in porphyry ore deposits: extracted by magmatic hydrothermal fluids as well as sulfide deposition and cannibalization, which is hindered for understanding the genesis of porphyry deposits. In order to investigate both the dynamic evolution processes and metallogenic responses of magmatic-hydrothermal system for these two mechanisms in detail, this project planned to simulate kinetic processes of the two mechanisms for the large-scale and efficient enrichment of metals in porphyry ore deposits using a hybrid computational modeling method, which has combined the advantages of both numerical simulation and the stochastic modelling (Monte Carlo method). Firstly, the multi-field coupling dynamic models will be established for simulating the evolution process for the enrichment of metallogenic metals in porphyry mineralization under the two different metallogenic mechanisms. Then, the numerical computational simulation model for the dynamic models will be constructed and the stochastic modeling approach applied to produce parameters for numerical modelling will be furtherly implemented. Finally, using the real data of Jiangxi Dexing super-large porphyry copper deposit to check reasonableness of the modelling results for the two metallogenic mechanisms, wishing to verify or/and falsify the efficient of them. The new ideas of computational modeling kinetic processes of porphyry mineralization could provide more scientific evidences for revealing the genesis of porphyry deposits (or large/super-large porphyry deposits), and will fatherly enrich and perfect the ore-forming and prospecting theories for porphyry deposits.

数值模拟与随机建模分别在研究地质过程动力学机制和分析表征地质事件或变量不确定性方面具有独特优势。当前，对斑岩矿床成矿金属大规模高效富集机制存在两种争议较大的认识：岩浆热液萃取模式与硫化物堆晶拆解模式，制约了斑岩矿床成矿机理的认识与发展。为了有效揭示这两种机制下斑岩岩浆-热液系统的动力学演化过程及其成矿响应情况。本项目将在两种机制动力学过程剖析以及前人工作的基础上，将数值模拟与随机建模的优势相结合，首先构建不同机制下斑岩矿床成矿金属富集的多场耦合动力学模型，进而实现相应的数值计算模型并提出基于边界条件和模型参数随机建模（蒙特卡洛模拟）的计算模拟新方法，最后进行基于德兴铜矿实测数据的数值模型计算与模拟结果的对比验证研究，以期证实或证伪两种不同机制的有效性。拓展了成矿动力学计算模拟的新思路，为揭示斑岩矿床（或大型/超大型斑岩矿床）的成因提供科学的理论依据，进一步丰富和完善斑岩矿床成矿与找矿理论。

数值模拟在研究地质过程动力学机制和分析表征地质事件或变量不确定性方面具有独特优势。当前，对斑岩矿床成矿金属大规模高效富集机制存在两种争议较大的认识：岩浆热液萃取模式与硫化物堆晶拆解模式，制约了斑岩矿床成矿机理的认识与发展。为了有效揭示这两种机制下斑岩岩浆-热液系统的动力学演化过程及其成矿响应情况，本项目在深入剖析斑岩矿床成矿金属大规模高效富集的两种机制动力学过程的基础上，构建了不同机制下斑岩矿床成矿金属富集成矿过程的地质概念模型及相应的几何实体模型，并进一步分析总结了该过程中应力应变、热传递、流体流动、质量传递的多场耦合数学-物理方程，建立了斑岩矿床成矿金属富集过程的力-热-流-质多场耦合动力学模型。随后进行了基于德兴铜矿实测数据的数值模型计算与模拟结果的对比验证研究，探究了不同地质参数对成矿金属富集的效率与规模的影响，斑岩岩浆-热液系统金属元素富集成矿过程中揭示了斑岩矿床岩浆-热液系统的动力学演化过程及其成矿响应情况，拓展了成矿动力学计算模拟的新思路，为斑岩矿床成矿金属元素高效富集的机制提供了数值模拟实验的新证据，进一步丰富和完善了斑岩矿床成矿与找矿理论。