川西北马脑壳金矿床流体相分离作用及其成矿意义

马脑壳金矿床是近年来在川西北地区发现的一大型微细浸染型矿床。本文通过对流体包裹体系统研究，指出了石英-(白钨矿)-辉锑矿脉型金矿化阶段成矿流体曾发生过较强的相分离作用，并运用热力学原理探讨了流体相分离机制下金的沉淀成矿机理，提出了微细浸染型金矿床形成过程中流体相分离作用与成矿的关系。

Phase Separation of Fluids in the Manaoke Gold Deposit of Northwestern Sichuan and Its Mineralization Significance

The Manaoke gold deposit is a large micro-grained disseminated type deposit found recently in northwestern Sichuan. It is located in Middle Triassic Zageshan Formation, with slates, sandstones and limestones as its main lithologic association. The ore belt is strictly controlled by a NW-striking second-order fault. The mineralization of the deposit can be classified into two types, viz. altered rock type and quartz vein type. The former type is of quartz-arsenopyrite-pyrite-native gold ore formation and is developed along the rock beds, whereas the latter type is of quartz-(scheelite)-stibnite-native gold ore formation and occurs crosscutting the rock beds. A systematic study on fluid inclusions shows that phase separation process happened in the ore-forming solutions at the quartz-(scheelite)-stibnite vein type gold mineralization stage. The paper has discussed the mechanism of gold deposition as the result of fluid phase separation process, and put forward the new view that the fluid phase separation process played an important role in the formation of industrial ore shoots during the formation of micro-grained disseminated gold deposits.