与金有关的深部流体成矿作用地球化学研究和热力学分析

Based on the study of Huangjindong gold deposit, Hunan, Rushan and Dazhuangzi gold deposits, Shandong, combining fluid inclusion data from the literatures, the characteristics of Au-forming fluids related to deep-derived sources are summarized, which belong to H2O-rich system (NaCl-CO2 -CH4体H2O-NaCl-CO2), with low to middle salinities and largely varying temperatures and pressures. Major geological and geochemical evidences are discussed related to deep-derived fluids. Using the equations of state of typical geofluid, H2O-NaCl-CO2 -CH4 system, simulation is conducted on its phase change and immiscibility properties, it shows that CO2 and/or CH4-bearing fluids are substantial important to the immiscibility, which occurs at low to middle temperatures and generally was caused by drop of pressure. According to the simulation data, density profile is established in a large scale from the surface of the crust down to the middle of the lithosphere, which varies from large to small, and then become large again at depths of tens kilometers. That provides a theoretical support to vertical fluid convection. .In addition, a study is focused on a rear earth element mineral, monazite , found firstly in the quartz veins of the Rushan gold deposit; Au-bearing arsenopyrite is researched by EPMA and HRTEM, structure gold is determined as an important state in the Huangjindong deposit; And a systematic work is geologically and geochemically performed on the Dazhuangzi deposit newly found at southwest margin of the Jiaobei terrene, which is believed a different type gold deposit from the ones found before in the middle to northeast part of the area. It is of big significance for understanding gold-forming mechanism and further prospecting work..

深部流体对许多矿床的形成至关重要。本专题拟以江南和胶东典型金矿为对象，通过地质地球化学解剖研究和对比，查明与深部流体有关金矿的基本特征及其特殊成矿条件。并拟通过热力学理论计算，对深部富挥发分超临界流体的性质和行为（相变规律、金属溶解能力和成矿机制等）进行分析探讨，为丰富深部流体成矿模式提供理论基础。