The Watershed tungsten deposit (49.2 Mt avg 0.14% WO₃) lies within the Mossman orogen, which comprises deformed Silurian-Ordovician metasedimentary rocks of the Hodgkinson Formation intruded by Carboniferous-Permian granites of the Kennedy Igneous Association. The Hodgkinson Formation in the Watershed area comprises skarn-altered conglomerate, psammite, and slate units that record four deformation events evolving from ductile, isoclinal, colinear folding with transposition (D₁–D₃) to brittle ductile shear zones (D₄). Multiple felsic to intermediate dikes cut across the metasedimentary rocks at Watershed including the following: (1) Carboniferous, monzonite dikes (zircon U/Pb age of 350 ± 7 Ma) emplaced during D_1–2; and (2) Permian granite plutons and dikes (zircon U/Pb ages of 291 ± 6, 277 ± 6, and 274 ± 6 Ma) and diorite (zircon U/Pb age of 281 ± 5 Ma) emplaced during D₄. Tungsten mineralization is largely restricted to skarn-altered conglomerate, which preserves a peak metamorphic mineralogy formed during ductile deformation and comprises garnet (Grt_40–87 Alm_0–35Sps_1–25Adr_0–16), actinolite, quartz, clinopyroxene (Di_36–59Hd_39–61Jhn_1–5), and titanite. A first mineralization event corresponds to the crystallization of disseminated scheelite in monzonite dikes (pre-D₃) and adjacent units, with scheelite grains aligned in the S_1–2 fabric and affected by D₃ folding. This event enriched the Hodgkinson Formation in tungsten. The bulk of the scheelite mineralization formed during a second event and is concentrated in multistaged, shear-related, quartz-oligoclase-bearing veins and vein halos (muscovite ⁴⁰Ar-³⁹Ar weighted average age of 276 ± 6 Ma), which were emplaced during D₄. The multistage veins developed preferentially in competent, skarn-altered conglomerate units and formed synchronous with four retrograde alteration stages. The retrograde skarn minerals include clinozoisite after garnet, quartz, plagioclase, scheelite, and phlogopite with minor sodium-rich amphibole, which formed during retrograde stages 1 and 2, accompanied by later muscovite, calcite, and chlorite formed during retrograde stage 3. Retrograde stage 4 was a late-tectonic, noneconomic sulfide stage. The principal controls on scheelite mineralization at Watershed were the following: (1) early monzonite dikes enriched in scheelite; (2) D₄ shear zones that acted as fluid conduits transporting tungsten from source areas to traps; (3) skarn-altered conglomerate lenses that provide a competent host to facilitate vein formation and a source for calcium to form scheelite; and (4) an extensional depositional environment characterized by vein formation and normal faulting, which provide trapping structures for tungsten-bearing fluids, with decompression being a likely control on scheelite deposition. The coexistence of scheelite with oligoclase in monzonite dikes and veins suggests that tungsten was transported as NaHWO40. Exploration in the area should target Carboniferous monzonite, associated with later syn-D₄ shear zones cutting skarn-altered conglomerate.

中文翻译：

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澳大利亚昆士兰州东北部的分水岭钨矿床：二叠纪变质钨矿化覆盖了石炭纪岩浆钨矿

分水岭钨矿床（49.2 Mt平均0.14％WO ₃）位于Mossman造山带内，包括由肯尼迪火成岩协会的石炭-二叠纪花岗岩侵入的霍奇金森组变形的志留纪-奥陶纪准沉积岩。分水岭地区的霍奇金森组包括矽卡岩蚀变的砾岩，滑石和板岩单元，记录了从变形，等斜，共线折叠转位（D ₁ –D ₃）到脆性韧性剪切区（D ₄）演变的四个变形事件。在分水岭的浅水沉积岩中切割了多个长英质至中级堤防：（1）D _1–2期间安放了石炭纪，蒙脱石堤防（锆石U / Pb年龄为350±7 Ma）_；（2）D ₄期间放置了二叠纪花岗岩岩体和堤坝（锆石U / Pb年龄为291±6、277±6和274±6 Ma）和闪长岩（锆石U / Pb年龄为281±5 Ma）。钨矿化在很大程度上仅限于矽卡岩蚀变的砾岩，它保留了韧性变形过程中形成的峰值变质矿物学，包括石榴石（Grt _40–87 Alm _0–35 Sps _1–25 Adr _0–16），阳起石，石英，斜辉石（Di _36-59高清_39-61。约_1-5），和榍。第一个矿化事件对应于在长石岩堤中弥散的白钨矿的结晶（D _3之前））和相邻单元，白钨矿颗粒在S _1-2织物中对齐，并受D ₃折叠的影响。这一事件丰富了钨的霍奇金森组。白钨矿成矿的大部分在第二个事件中形成，并集中在多级，剪切相关，含石英寡糖的静脉和晕圈（白云母⁴⁰ Ar- ³⁹ Ar加权平均年龄276±6 Ma）中，在第_4天。多级矿脉优先在称职，矽卡岩化的砾岩体中发育，并与四个逆行蚀变阶段同步形成。逆行矽卡岩矿物包括石榴石，石英，斜长石，白钨矿和金云母后的斜长石矿物，在逆行阶段1和2期间形成了少量的富钠闪石，伴随着在逆行阶段3之后形成的白云母，方解石和绿泥石。 4是晚期构造的非经济硫化物阶段。流域白钨矿成矿的主要控制措施如下：（1）富含白钨矿的早期蒙山石堤；（2）₄剪切带充当将钨从源区传输到陷阱的流体导管；（3）矽卡岩蚀变的砾岩晶状体，可提供有力的宿主以促进静脉形成，并为钙形成白钨矿提供来源；（4）以静脉形成和正常断裂为特征的伸展沉积环境，为含钨流体提供了捕集结构，减压可能是白钨矿沉积的控制手段。白铁矿和脉石中白钨矿与寡糖酶的共存表明钨以NaHWO40的形式运输。该地区的勘探应针对石炭纪的蒙脱石，并与随后的syn-D ₄剪切带切割矽卡岩蚀变的砾岩相关。