Structural controls on Ni-Cu sulfide mineralization and metal mobility at the Garson Mine, Sudbury

加森矿是安大略省世界级萨德伯里矿营中的几个镍铜矿之一。加拿大约三分之二的镍年产量来自萨德伯里矿。通常，镍铜矿床位于有1.85亿年历史的萨德伯里火成岩的底部。当它们形成时，重金属硫化物金属液滴从冷却的岩浆中分离出来，聚集在火成岩杂岩的底部。在该杂岩结晶数百万年后，萨德伯里岩石在北美大陆的构造碰撞增长期间发生断层、褶皱和剪切。包括加尔森矿床在内的几个矿床，在这次构造事件中发生了变形。尽管这改变了矿床的形状、金属含量和硫化物矿物的分布。在加尔森矿，镍铜硫化物矿化发生在两个主要的剪切带内。但剪切变形对矿化性质和分布的影响程度尚不确定。在变形过程中，矿化要么基本保持原地，在硫化物矿物作为高温延展性浆体的韧性流动过程中，以及在沿剪切带迁移的热液流体内的溶液中金属和硫的运输过程中，或被活化。拟议的研究将确定硫化物矿物受这种变形影响的程度，并将确定在硫化物活化过程中，溶液运输与韧性固体流动的相对重要性。它将进一步表征沿剪切带金属聚集的有利构造部位，并将识别可用于引导镍-铜矿化的地球化学富/亏特征。

The Garson Mine is one of several nickel-copper mines in the world-class Sudbury mining camp in Ontario.  Two thirds of Canada's annual nickel production is from Sudbury mines.  The nickel-copper deposits occur at the base of the 1850 million years old Sudbury Igneous Complex.  They formed as heavy sulphide metal droplets segregated from the cooling magma and accumulated along the floor of the igneous complex.  Several millions of years after crystallization of the complex, the Sudbury rocks were faulted, folded, and sheared during tectonic collisional growth of the North American continent.  Several deposits, including the Garson deposit, were deformed during this tectonic event.  This changed the shape of the deposits, their metal content, and distribution of sulphide minerals.  At the Garson Mine, Ni-Cu sulfide mineralization occurs within two main shear zones.  The degree to which shear deformation has affected the nature and distribution of the mineralization is uncertain.  Mineralization either remained largely in place during deformation, or was mobilized during ductile flow of sulfide minerals as high-temperature malleable pastes and during transport of metals and sulfur in solution within hydrothermal fluids that migrated along the shear zones.  The proposed research will establish the degree to which sulfide minerals have been affected by this deformation and will determine the relative importance of solution transport versus ductile solid flow during mobilization of the sulfides.  It will further characterize favorable structural sites for the concentration of metals along the shear zones and will identify geochemical enrichment /depletion signatures that can be used to vector toward nickel-copper mineralization.