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

加尔森矿是位于安大略的世界级萨德伯里采矿营地的几个镍铜矿之一。 加拿大每年镍产量的三分之二来自萨德伯里矿山。 镍铜矿床位于18.5亿年前的萨德伯里火成杂岩的底部。 它们形成为重硫化物金属液滴，从冷却的岩浆中分离出来，并沿着火成岩复合体的底部积聚。 在复合体结晶后的数百万年，萨德伯里岩石在北美大陆的构造碰撞生长过程中发生了断层，褶皱和剪切。 包括加尔森存款在内的几个存款在这一构造事件中发生了变形。 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剪切带内。 剪切变形对矿化的性质和分布的影响程度尚不确定。 矿化在变形过程中大部分保持在原地，或者在硫化物矿物作为高温韧性膏体的韧性流动过程中以及在热液流体中的溶液中的金属和硫的运输过程中被动员，热液流体沿沿着剪切带迁移。 拟议的研究将建立硫化物矿物受到这种变形的影响的程度，并将确定在硫化物的流动过程中，溶液运输与韧性固体流动的相对重要性。 它将进一步确定有利的构造部位，使金属沿着剪切带富集，并将确定可用于引导镍铜矿化的地球化学富集/贫化特征。

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.