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的萨德伯里采矿营地的几个镍铜矿之一。加拿大每年三分之二的镍产量来自萨德伯里矿。镍铜矿床出现在有1850万年历史的萨德伯里火成岩杂岩的底部。它们是由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而形成的。在杂岩结晶几百万年后，萨德伯里的岩石在北美大陆的构造碰撞生长过程中被断裂、折叠和剪切。包括Garson矿床在内的几个矿床在这次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Garson矿，镍铜硫化物矿化发生在两个主要剪切带内。剪切变形对矿化性质和分布的影响程度尚不确定。矿化要么在变形过程中大部分保持在原位，要么在硫化物矿物作为高温可塑糊状物的韧性流动过程中被动员起来，要么在金属和硫溶液在热液流体中沿着剪切带迁移的过程中被动员起来。拟议的研究将确定硫化物矿物受这种变形影响的程度，并将确定硫化物动员过程中溶液输送与韧性固体流动的相对重要性。它将进一步描述沿剪切带富集金属的有利构造位置，并将确定可用于指向镍铜成矿的地球化学富集/枯竭特征。

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.