The Westwood deposit (4.5 Moz Au) is hosted in the 2699–2695 Ma Bousquet Formation volcanic and intrusive rocks, in the eastern part of the Blake River Group, southern Abitibi greenstone belt. The Bousquet Formation is divided in two geochemically distinct members: a mafic to intermediate, tholeiitic to transitional lower member and an intermediate to felsic, transitional to calc-alkaline upper member. The Bousquet Formation is cut by the synvolcanic (2699–2696 Ma) polyphase Mooshla Intrusive Complex, which is cogenetic with the Bousquet Formation.The deposit contains three strongly deformed (D₂ flattening and stretching), steeply S-dipping mineralized corridors that are stacked from north to south: Zone 2 Extension, North Corridor, and Westwood Corridor. The North and Westwood corridors are composed of Au-rich polymetallic sulfide veins and stratabound to stratiform disseminated to massive sulfide ore zones that are spatially and genetically associated with the calcalkaline, intermediate to felsic volcanic rocks of the upper Bousquet Formation. The formation of the disseminated to semimassive ore zones is interpreted as strongly controlled by the replacement of porous volcaniclastic rocks at the contact with more impermeable massive cap rocks that helped confine the upflow of mineralizing fluids. The massive sulfide lenses are spatially associated with dacitic to rhyolitic domes and are interpreted as being formed, at least in part, on the paleoseafloor. The epizonal, sulfide-quartz vein-type ore zones of the Zone 2 Extension are associated with the injection of subvolcanic, calc-alkaline felsic sills and dikes within the lower Bousquet Formation. These subvolcanic intrusive rocks, previously interpreted as lava flows, are cogenetic and coeval with the intermediate to felsic lava flows and domes of the upper Bousquet Formation.The change from fractional crystallization to assimilation- and fractional crystallization-dominated processes and transitional to calc-alkaline magmatism is interpreted to be responsible for the development of the auriferous ore-forming system. The Westwood deposit is similar to some Phanerozoic Au ± base metal-rich magmatic-hydrothermal systems, both in terms of local volcano-plutonic architecture and inferred petrogenetic context. The complex volcanic evolution of the host sequence at Westwood, combined with its proximity to a polyphase synvolcanic intrusive complex, led to the development of one of the few known large Archean subaqueous Au-rich magmatic-hydrothermal systems.

中文翻译：

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加拿大南部 Abitibi 绿岩带 Westwood 矿床：太古宙富金多金属岩浆热液系统——第一部分：火山构造、变形和变质作用

Westwood 矿床（4.5 Moz Au）位于 Abitibi 绿岩带南部布莱克河群东部的 2699-2695 Ma Bousquet 组火山和侵入岩中。Bousquet 组在地球化学上分为两个不同的成员：镁铁质到中层、拉斑到过渡下段和中间到长英质、过渡到钙碱性上段。Bousquet组被同生火山（2699～2696 Ma）多相Mooshla侵入杂岩切割，与Bousquet组共生。该矿床包含三个强烈变形（D ₂平坦和伸展），从北到南堆叠的陡峭 S 倾角矿化走廊：Zone 2 Extension、North Corridor 和 Westwood Corridor。North 和 Westwood 走廊由富含金的多金属硫化物脉组成，层状排列成层状，扩散到块状硫化矿带，在空间和成因上与上 Bousquet 组的钙碱性、中长英质火山岩相关。浸染至半块状矿石带的形成被解释为受到多孔火山碎屑岩与更不透水块状盖层接触的置换的强烈控制，这些盖层有助于限制成矿流体的上流。巨大的硫化物透镜在空间上与英安岩到流纹岩穹顶相关联，并被解释为至少部分形成，在古海底。Zone 2 Extension 的带状硫化物石英脉型矿带与下 Bousquet 组内注入次火山、钙碱性长英质岩床和岩脉有关。这些次火山侵入岩，以前被解释为熔岩流，与中间到长英质熔岩流和上 Bousquet 组的圆顶是共生的。岩浆作用被解释为负责金矿形成系统的发展。Westwood 矿床与一些显生宙的 Au ± 富含贱金属的岩浆热液系统相似，无论是在当地火山 - 深成体系结构方面还是在推断的岩石成因方面。