The Reward mine at Hill End hosts structurally controlled orogenic gold mineralization in moderately S plunging, high-grade gold shoots located at the intersection between a late, steeply W dipping reverse fault zone and E-dipping, bedding-parallel, laminated quartz veins (the Paxton’s vein system). The mineralized bedding-parallel veins are contained within the middle Silurian to Middle Devonian age, turbidite-dominated Hill End trough forming part of the Lachlan orogen in New South Wales. The Hill End trough was deformed in the Middle Devonian (Tabberabberan orogeny), forming tight, N-S–trending, macroscopic D₂ folds (Hill End anticline) with S₂ slaty cleavage and associated bedding-parallel veins.Structural analysis indicates that the D₂ flexural-slip folding mechanism formed bedding-parallel movement zones that contained flexural-slip duplexes, bedding-parallel veins, and saddle reefs in the fold hinges. Bedding-parallel veins are concentrated in weak, narrow shale beds between competent sandstones with dip angles up to 70° indicating that the flexural slip along bedding occurred on unfavorably oriented planes until fold lockup. Gold was precipitated during folding, with fluid-flow concentrated along bedding, as fold limbs rotated, and hosted by bedding-parallel veins and associated structures. However, the gold is sporadically developed, often with subeconomic grades, and is associated with quartz, muscovite, chlorite, carbonates, pyrrhotite, and pyrite.East-west shortening of the Hill End trough resumed during the Late Devonian to early Carboniferous (Kanimblan orogeny), producing a series of steeply W dipping reverse faults that crosscut the eastern limb of the Hill End anticline. Where W-dipping reverse faults intersected major E-dipping bedding-parallel veins, gold (now associated with galena and sphalerite) was precipitated in a network of brittle fractures contained within the veins, forming moderately S plunging, high-grade gold shoots. Only where major bedding-parallel veins were intersected, displaced, and fractured by late W-dipping reverse faults is there a potential for localization of high-grade gold shoots (>10 g/t). A revised structural history for the Hill End area not only explains the location of gold shoots in the Reward mine but allows previous geochemical, dating, and isotope studies to be better understood, with the discordant W-dipping reverse faults likely acting as feeder structures introducing gold-bearing fluids sourced within deeply buried Ordovician volcanic units below the Hill End trough.A comparison is made between gold mineralization, structural style, and timing at Hill End in the eastern Lachlan orogen with the gold deposits of Victoria, in the western Lachlan orogen. Structural styles are similar where gold mineralization is formed during folding and reverse faulting during periods of regional east-west shortening. However, at Hill End, flexural-slip folding-related weakly mineralized bedding-parallel veins are reactivated to a lesser degree once folds lock up (cf. the Bendigo zone deposits in Victoria) due to the earlier effects of fold-related flattening and boudinage. The second stage of gold mineralization was formed by an array of crosscutting, steeply W dipping reverse faults fracturing preexisting bedding-parallel veins that developed high-grade gold shoots. Deformation and gold mineralization in the western Lachlan orogen started in the Late Ordovician to middle Silurian Benambran orogeny and continued with more deposits forming in the Bindian (Early Devonian) and Tabberabberan (late Early-Middle Devonian) orogenies. This differs from the Hill End trough in the eastern Lachlan orogen, where deformation and mineralization started in the Tabberabberan orogeny and culminated with the formation of high-grade gold shoots at Hill End during renewed compression in the early Carboniferous Kanimblan orogeny.

中文翻译：

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澳大利亚新南威尔士州希尔德山奖励矿高品位金芽的结构控制

位于希尔恩德（Hill End）的雷德（Reward）矿床位于S倾角为W的深反向断裂带与E倾角，平行平行，层状石英脉（ Paxton的静脉系统）。平行于矿床的矿化脉包含在志留纪至中泥盆世时代，以浊石为主的山端槽中，形成了新南威尔士州拉克兰造山带的一部分。Hill End槽在中泥盆世（Tabberabberan造山运动）中变形，形成紧密的，NS趋势的宏观D ₂褶皱（Hill End背斜线），具有S ₂片状劈裂和相关的顺层平行脉。结构分析表明，D ₂弯曲滑动折叠机制形成了平行的床层运动区域，在折叠铰链中包含弯曲滑动的双相体，平行的床层静脉和马鞍礁。平行于顺层的脉层集中在称职砂岩之间的薄弱，狭窄的页岩层中，倾角最大为70°，这表明沿顺层的挠曲滑动发生在方向不利的平面上，直到褶皱闭锁。折叠过程中析出了金，随着四肢的旋转，流体沿着床上用品集中，并由床上用品平行的静脉和相关结构占据。然而，黄金是偶发性的，通常具有次经济品位，并且与石英，白云母，绿泥石，碳酸盐，黄铁矿和黄铁矿有关。 ），产生了一系列陡峭的W倾角反向断层，这些断层横切了Hill End背斜线的东边。W浸入逆断层与E浸入层平行的主脉相交的地方，金（现在与方铅矿和闪锌矿相关）沉淀在脉内的脆性断裂网络中，形成中等程度的S倾角，高档金芽。只有在主要的平行于顺层的脉被相交，错位和晚W倾倒断层断裂的地方，才有可能定位高品位的金枝（> 10 g / t）。修改后的Hill End地区的结构历史不仅可以解释Reward矿山中金矿的位置，还可以更好地理解先前的地球化学，测年和同位素研究，与不连续的W倾倒断层可能作为馈线结构引入了在Hill End槽下方深埋的奥陶纪火山岩单元中开采的含金流体，对东部的Hill End的金矿化，构造样式和时间进行了比较拉克兰造山带，维多利亚州西部的拉克兰造山带，有维多利亚的金矿床。构造样式相似，在折叠过程中形成金矿化，在东西向区域缩短期间形成反向断层。但是，在希尔德山端，由于褶皱相关的展平和松土作用较早，一旦褶皱被锁定（与维多利亚州本迪戈地区的沉积物相比），与弯曲滑动折叠有关的弱矿化的层状平行矿脉就会重新激活至较小的程度。 。金矿化的第二阶段是由一系列横切的，陡峭的W浸入反向断层形成的，这些断层使早已存在的顺层平行脉裂开，从而形成了高级金枝。拉克兰造山带西部的变形和金矿化开始于奥陶纪晚期至志留纪贝纳姆邦造山带中段，并继续在宾甸（早泥盆世）和塔伯拉贝兰（早中泥盆世晚期）造山带中形成更多的沉积物。这与东部拉克兰造山带的希尔德槽不同，后者在塔伯拉贝兰造山带开始变形和矿化，并最终在早期石炭纪卡尼姆布兰造山带的新压缩过程中，在希尔德形成高品位的金芽。陡峭的W倾覆反向断裂使早已形成的平行床脉破裂，形成了高级金芽。拉克兰造山带西部的变形和金矿化开始于奥陶纪晚期至志留纪贝纳姆邦造山带中段，并继续在宾甸（早泥盆世）和塔伯拉贝兰（早中泥盆世晚期）造山带中形成更多的沉积物。这与东部拉克兰造山带的希尔德槽不同，后者在塔伯拉贝兰造山带开始变形和矿化，并最终在早期石炭纪卡尼姆布兰造山带的新压缩过程中，在希尔德形成高品位的金芽。陡峭的W倾覆反向断裂使早已形成的平行床脉破裂，形成了高级金芽。拉克兰造山带西部的变形和金矿化开始于奥陶纪晚期至志留纪贝纳姆邦造山带中段，并继续在宾甸（早泥盆世）和塔伯拉贝兰（早中泥盆世晚期）造山带中形成更多的沉积物。这与东部拉克兰造山带的希尔德槽不同，后者在塔伯拉贝兰造山带开始变形和矿化，并最终在早期石炭纪卡尼姆布兰造山带的新压缩过程中，在希尔德形成高品位的金芽。拉克兰造山带西部的变形和金矿化开始于奥陶纪晚期至志留纪贝纳姆邦造山带中段，并继续在宾甸（早泥盆世）和塔伯拉贝兰（早中泥盆世晚期）造山带中形成更多的沉积物。这与东部拉克兰造山带的希尔德槽不同，后者在塔伯拉贝兰造山带开始变形和矿化，并最终在早期石炭纪卡尼姆布兰造山带的新压缩过程中，在希尔德形成高品位的金芽。拉克兰造山带西部的变形和金矿化开始于奥陶纪晚期至志留纪贝纳姆邦造山带中段，并继续在宾甸（早泥盆世）和塔伯拉贝兰（早中泥盆世晚期）造山带中形成更多的沉积物。这与东部拉克兰造山带的希尔德槽不同，后者在塔伯拉贝兰造山带开始变形和矿化，并最终在早期石炭纪卡尼姆布兰造山带的新压缩过程中，在希尔德形成高品位的金芽。