【作者】 赵军；

【导师】 毛景文； 张作衡；

【作者基本信息】 长安大学 ， 矿产普查与勘探， 2013， 博士

【摘要】 新疆阿吾拉勒山西段为晚石炭世—二叠纪的陆相火山岩区，区内分布众多与陆相火山作用有关的铜矿床（点）。本论文对该区二叠纪火山岩、次火山岩和侵入岩进行了详细的岩石学和岩石地球化学研究，并对花岗岩类侵入岩开展了LA-ICP-MS锆石U-Pb测年分析。同时，对区内5个典型铜矿床（点）进行了详细的矿床地质特征对比研究、流体包裹体和碳、氧、硫、铅稳定同位素分析。在此基础上，对该区铜矿类型进行了重新划分，讨论了不同类型铜矿床的成矿机理和成矿环境，总结了区域铜矿成矿规律，建立了成矿模式，并指出了下一步找矿方向。论文取得的主要成果和认识如下：1．阿吾拉勒山西段下二叠统陆相双峰式火山岩、次火山岩和浅成-超浅成侵入岩以碱性和偏碱性系列为主，整体高Na2O、高Al2O3、低TiO2、富碱，亏损Nb、Ta。三类岩石具有明显不同的成因和岩浆来源，其中，下二叠统玄武岩以碱性玄武岩为主，来源于弱亏损地幔，并受到了少量下地壳物质的混染；次火山岩来源于前寒武纪基底物质（老地壳）的重熔，流纹斑岩兼具S型和A型花岗岩的特征；中—酸性侵入岩可能来源于玄武质下地壳的熔融，但有较多石炭纪岛弧火成岩（新地壳）的加入，花岗岩类为I型花岗岩。2．该区晚古生代晚期的4个花岗岩类岩体锆石U-Pb年龄结果介于278.2±0.8Ma～312.9±1.3Ma之间，与区域火山活动主要发生在晚石炭世—早二叠世一致。但是，这些岩石中含有较多的继承锆石，其年龄值主要分布在早石炭世—晚石炭世之间，可能代表了源岩中加入了石炭纪火成岩的物质。3．群吉萨依辉绿玢岩中含有大量继承变质锆石，其年龄值较一致，介于1781.2±7.7Ma～1807.1±5.1Ma之间，平均为1794.8±4.7Ma，这是西天山地区目前获得的最老的锆石年龄。109矿区流纹斑岩中的继承变质锆石年龄结果也存在750Ma～1254Ma（6个）和1739Ma～1961Ma（4个）两组年龄。尽管这些锆石均为继承变质锆石，但与前人获得的西天山前寒武纪变质岩Nd模式年龄、岩浆锆石年龄和变质事件时代较为一致，说明该区不仅存在早元古代晚期的结晶基底，而且早二叠世次火山岩的形成还与这些前寒武纪基底岩石密切相关。4．重新对阿吾拉勒山西段的铜矿类型进行了划分，将其简化为次火山岩型和热液脉型两种类型。次火山岩型铜矿床（点）产出于中、南部地区，赋矿地层为下二叠统底部或上部火山岩地层，受火山机构中的次火山岩体和断裂破碎带控制，成矿流体规模较小，形成于较“干”的地质环境，成矿物质以地幔或深部岩浆源为主；热液脉型铜矿床（点）产出于北部地区，赋矿地层为下二叠统顶部火山岩地层与中二叠统沉积地层接触面附近，成矿流体为一种中-低温、中-低盐度流体，由火山热液和大气降水混合形成，规模较大，成矿物质来源具有多源性，但以地幔源为主。5．该区晚古生代晚期的裂谷演化持续时间可能较短，早二叠世是其主要阶段，早二叠世末期曾形成很小范围的海盆环境。但中二叠世以后，构造环境由拉伸转为挤压，裂谷演化终止。因此，该区的裂谷为一规模较小的不成熟裂谷。区域成矿与裂谷演化具有空间一致性。裂谷演化导致的陆相火山活动为铜矿的形成提供了矿源层。矿源层的差异、控矿构造的不同以及火山活动的强弱决定了在裂谷带南北不同部位形成两种不同类型的铜矿床。6．由于裂谷拉张规模较小，导致岩浆分异演化较弱，期次少，埋深浅，流体来源和规模均有限，成矿物源缺乏持续供给，因此，该区很难形成规模较大的铜矿床。相较而言，热液脉型比次火山岩型具有更好的成矿条件和复杂的控矿因素，是该区今后铜矿勘查的重点。受成矿环境的制约，区内铜矿形成深度较浅，深部找矿潜力不大，但个别矿床深部仍具一定的找矿前景，如奴拉赛铜矿和克孜布拉克铜矿。更多还原

【Abstract】 Including huge thick strata of continental volcanic rocks of upper CarboniferousSeries-Permian, the Western Awulale Mountain have many copper deposits which are relatedto continental volcanism. Based on the petrology, geochemistry and geochronology researchof Permian volcanic rocks, subvolcanic rocks and intrusive rocks, this thesis completed fluidinclusion and stable isotope research for five typical copper deposits in this district. Accordingto these research works, the copper deposits types are reclassified, metallogenic mechanismand environment are analyzed. Moreover, this thesis summarizes the the metallogenicregularities of these copper deposits, and discusses the mineralization of this district. Themain innovation and new viewpoints are summarized as following:1. The typical bimodal volcanic rocks(basalts-rhyolite), subvolcanic and hypabyssalintrusive rocks of lower Permian in western Awulale Mountain are alkali and meta-alkaliseries which are generally characterized with higher Na2O and Al2O3contents, lower TiO2content and alkali-rich. Different rock types have different geochemical features which reflectthat they have diverse origin and magma sources. The basaltic magma is derived fromweak-depleted mantle. The subvolcanic rocks possess the characteristcs of S and A-typegranite which are production resulted from remelting of Precambrian basement rocks(oldcrust). Intermediate-acid intrusive rocks are I-type granite and related to the partial melting ofbasaltic lower crust, but many Carboniferous island-arc igneous rocks(new crust) are addedinto its magma.2. LA-ICP-MS U-Pb dating of magmatic zircons from the four granitic rocks in westernAwulale Mountain yield weighted average206Pb/238U ages from278.2±0.8Ma to312.9±1.3Ma, which reveal that the intrusion of magma in late Paleozoic occure from lateCarboniferous to early Permian. Some residual zircon cores have several groups ofCarboniferous age, indicating that the source of the granitic rocks likely containsCarboniferous island arc magmatic rocks.3. U-Pb dating of metamorphogenic zircons from the diabase yield207Pb/206Pb ages from1781.2±7.7Ma to1807.1±5.1Ma and weighted average age of1794.8±4.7Ma which is theoldest age of zircons in western Tianshan Mountain. Similarly, the age results of rhyolite in109ore district include two groups of ages from1739Ma to1961Ma and750Ma to1254Ma.These age results of metamorphogenic zircons are consistent with the Nd model ages,magmatic zircon ages and metamorphic ages of Precambrian metamorphic rocks in western Tianshan Mountain, which indicate that the crystalline basement has been formed in latePaleoproterozoic and the origin of subvolcanic rocks are related to these Precambrianbasement rocks.4. The copper deposits are reclassified to subvolcanic rock-type(SVR) and hydrothermalvein-type copper deposits(HTV). The SVR copper deposits occur in bottom and top strata oflower Permian Series; the orebodies are closely controlled by subvocanic rocks and faults;metal and vein minerals are less; the wall-rock alteration are generally weak; the metallogenicfluid are small size and single source which originate from a dry environment; theore-forming minerals are from deep magma. The HTV copper deposits occur near theinterface of top strata of lower Permian Series and bottom strata of intermediate PermianSeries; the metallogenic fluid are middle-lower temperature and salinity which is mixture ofvolcanic hydrothermal and circulated meteoric water; the ore-forming minerals source iscomplexity which include crustal and mantle source.5. The duration of the late Paleozoic rift evolution perhaps is short and the early Permianis its main stage in western Awulale Mountain. At the end stage of early Permian, sea basinhas been formed shortly in small scale. The rift evolution has ended because the tectonicsetting is changed from extension to compression after middle Permian. So, the rift is smallscale and immature. The regional mineralization is spatially consistent with the rift evolution.The continental volcanic generate numourous volcanic rocks and sedimentary strata whichconstitute the ore-source bed. The formation of different Cu deposit-types in different positonare controlled by the different mineral sources, structure and strength of continental volcanismcaused by the Permian rifting.6. The rift system has a small stretching extent in western Awulale Mountain whichcause the differentiation and evolution of magma activities are weak, accordingly, the igneousrocks are lack of multi-phase and hypabyssal or super-hypabyssal. In this environment, thesource and size of ore-forming fluids are finite, which makes against the formation of largercopper deposits. Comparatively, the hydrothermal vein-type copper deposits are moreimportant than subvolcanic rock-type copper deposits for exploration. Constrained bymetallogenic settings, the forming depth of copper deposits is shallow, thus, the prospect ofdeep exploration is generally not good. But, one or two deposits perhaps have relatively goodprospect for deep exploration, especially for Nulasai and Kezibulake copper deposits.更多还原