浅成岩体热液成矿系统流体超压和泄压及其动力学计算模拟

This program is designed to probe the intrusion-trigged geodynamic processes of fluid overpressure, rock fracturing, fluid decompression, ore deposition and their controlling factors in the hydrothermal mineralization systems that are closely associated with the shallow intrusions，through researching the deposits of Dongguashan and Anqing Cu skarns in the middle and lower Yangtze River district, Chehugou Cu-Mo porphyry in the Chifeng district, and Dawangding Au porphyry in the Dayaoshan Au belt. In order to achieve the purposes, the morphologic and scale measuring and statistics analyzing of rock cracks, micro-detecting of fluid inclusions and computational modeling of geodynamic processes are used to carry out the researching work. The spatial pattern and mechanism for fracturing of the ore-hosting rock are discussed through measuring and fractal statistics of the macro-morphology and size of the ore-bearing fractures and the mineralized breccias. The pale-pressure of fluids when they trapped in the ore is estimated by a set of methods based on systematically detecting the temperature and composition of the fluid inclusions. The mechanism for fluid overpressure and decompression and its association with ore formation are deduced through analyzing fluid pressure variation and their relationship to the ore-related intrusion, structural and petrological setting and metamorphic reaction. Finally, a set of 3D dynamic models of ore mineralization systems are constructed on the platforms of GOCAD, FLAC and TOUGHREACT, for simulating the geodynamics of coupled deformation, thermal transfer, fluid flow and chemical reaction in the fluid saturated porous medium. The theory model of the mechanism for fluid overpressure and decompression trigged by intrusion and its controlling on ore formation will be created through a set of computational modeling experiments under various conditions and comparison analyzing of the modeling results. The accomplishments achieved in this program must be very important for understanding the shallow intrusion-related mineralization and for facilitating ore prediction of the shallow intrusion-related ore deposits.

选择长江中下游的冬瓜山和安庆矽卡岩铜矿床、赤峰车户沟斑岩铜钼矿床和大瑶山大王顶斑岩金矿为对象，以岩石破裂形态测量与分形统计、流体包裹体测试和动力学计算模拟为主要手段，研究浅成岩体引发流体超压－岩石破裂－流体泄压－矿石沉淀的动力学过程和控制因素。通过对含矿裂隙和角砾岩的几何测量与统计，分析岩石破裂的空间规律与原因。通过流体包裹体的温度和成分的系统测试，以多种方法求取流体被捕获时的压力。通过分析压力变化及其与成矿岩体、构造与岩石环境以及变质反应之间的关系，推测流体超压和泄压机制及其与成矿的关系。利用GOCAD、FLAC和TOUGHREACT等平台构建成矿系统三维动力学模型，进行含水多孔介质的变形-传热-流体流动-化学反应耦合动力学计算模拟。根据一系列不同条件下的计算模拟实验结果的对比分析，建立岩体引发流体超压-泄压的动力学机制及其对成矿控制的理论模式。对浅成岩体成矿分析和成矿预测具有重要意义。

选择车户沟铜斑岩钼矿、冬瓜山矽卡岩铜金矿和大王顶斑岩金矿为对象，以流体包裹体测试和动力学计算模拟为主要手段，研究浅成岩体引发流体超压－岩石破裂－流体泄压－矿石沉淀的动力学过程和控制因素。通过对含矿裂隙和角砾岩的几何测量与统计，分析岩石破裂的空间规律与原因。通过流体包裹体的温度和成分的系统测试，以多种方法求取流体被捕获时的压力。通过分析压力变化及其与成矿岩体、构造与岩石环境以及变质反应之间的关系，推测流体超压和泄压机制及其与成矿的关系。利用GOCAD和FLAC 等平台构建成矿系统三维动力学模型，进行含水多孔介质的多过程耦合动力学计算模拟。根据一系列不同条件下的计算模拟实验结果的对比分析，建立岩体引发流体超压-泄压的动力学机制及其对成矿控制的理论模式。项目已完成了对三个矿床的调查和计算模拟研究工作。通过这些研究，我们已发现：在这些浅成岩体成矿系统中，源自岩体的超压力在矿体的形成和定位中起着非常重要的作用，其作用机制也非常复杂。利用这些成果已写出两篇论文，其中一篇已被国际知名SCI期刊“地球化学勘查”正式接受。