云南思茅-南坪盆地边缘造山带金(铜)成矿流体动力学

从研究云南思茅 -南坪盆地边缘造山带金 (铜 )成矿流体的地质地球化学特征和物理化学条件入手 ,通过氢 -氧、碳 -氧、氦 -氩同位素组成示踪和矿物流体包裹体温度 -压力、流体成分测试及物理化学参数计算 ,认为成矿溶液主要来自大气降水 ,并且成矿物质具有壳源的特点 ,不能排除构造 /岩浆活动中其他壳源流体加入的可能性 ,其性状为浅成 (低压 )、低温、高盐度、弱碱性和弱还原性 ,流体组分别具有Na+ >K+ 和Ca2 + +Mg2 + 、Cl->F-的特点 ,还原形式存在的硫占绝对优势 ,它对金的迁移和沉淀起着关键的作用 ;运用古水文地质学方法模拟成矿流体的水动力场与排泄条件 ,强调多成因含矿流体受古水文动力场运移、分布形式制约 ,高能量、高矿化度成矿流体经历漫长的地下反复溶滤、渗透、岩浆和构造驱动双重作用下 ,在水动力低压区排泄、沉淀富集成矿 .

Au (Cu) Ore-Fluid Dynamics in Bordering Orogenic Belt of Simao-Nanping Basin, Yunnan Province

We studied geologic and geochemical characteristics and physical chemical condition of the Au (Cu) ore fluid, bordering the orogenic belt of the Simao Nanping basin. The studies of isotopic tracing on H-O, C-O, He-Ar, T and p , composition in the mineral inclusions testing and their physical chemical parameter calculation in the fluid inclusion indicate that ore forming fluid is derived from meteoric water and that the ore forming materials may be from crustal source and other origin fluid joined. The fluid presents some characteristics such as epithermal, high salinity, alkalescency and deoxidizescency, Na +>K + and Ca 2+ +Mg 2+ , Cl ->F - in the compositions. In the fluid, S 2- is dominated and plays a key role in transference and precipitation of Au. The hydrodynamic field and discharge conditions are simulated by paleo hydrogeologic method with a stress on the control of migration and distribution pattern of paleo hydrodynamics field over the multi genetic ore fluid. The ore fluid of high energy and high degree of mineralization is discharged in the low hydrodynamics pressure area and precipitated to form the ore after a long time of repeated leaching and permeation, driven by magmatic dynamics and tectonics.