| 论东天山土屋-延东(斑岩)铜矿的容矿岩 |
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| 引用本文：.2002.Host Rocks of Tuwu_Yandong (Porphyry) Copper Deposit in Tianshan Mountains[J].Mineral Deposits,21(4):331~340 |
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| 基金项目:国家自然科学基金(编号：4997032)及国土资源部地质大调查项目(编号：K4.3.2.1) |
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| 中文摘要:通过对土屋_延东(斑岩)铜矿容矿岩的时空分布、物质组分及结构构造研究，认为该矿床的容矿岩是一套由中酸性_基性火山岩(包括沉凝灰岩)经富Na、Si热流体交代而成的钠质酸性_基性火山岩，按岩性及结构分以下4类：①具斑状或似斑状结构的钠质酸性_中酸性火山岩或称之为钠长石英斑岩与石英斑岩，它常位于矿体的上部，约占容矿岩的20%；②以自形、半自形板状、粒状交织结构为主的(含少量斑晶)钠质中酸性_中基性火山岩，或称之为安山玢岩，它常位于矿体的中部及中下部，约占容矿岩的50%；③以自形、半自形板状、粒状交织结构为主的富铝基性火山岩，或称之为高铝玄武岩，它常位于矿体的下部及底板围岩，约占容矿岩的20%；④以凝灰结构、碎屑结构为主的钠质中酸性_中基性火山碎屑岩，它常位于矿体的下部及底板围岩，约占容矿岩的10%。 |
| 中文关键词:岩石学 斑岩铜矿 容矿岩 Na-Si交代 延东-土屋 |
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| Host Rocks of Tuwu_Yandong (Porphyry) Copper Deposit in Tianshan Mountains |
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| Abstract:The Tuwu-Yandong (porphyry) copper deposit, a large-size copper deposit discovered recently in China, is located at the juncture of the Tarim plate and the Junggar plate, in the Late Paleozoic Qoltag island arc belt on the northeastern margin of the Central Tianshan paleo_uplift. The host rocks of this deposit occur in a transitional zone between the Second Member and Third Member of the Upper Paleozoic Qi'eshan Group. Geologists hold different views on the lithology and genetic mechanism of the host rocks. The authors consider that the host rocks of this deposit comprise a suite of sodic acid_basic volcanic rocks (including sedimentary tuffs) formed by metasomatism of intermediate_acid_basic volcanic rocks due to the action of Na_and Si_rich hydrothermal fluids. According to lithologies and textures, four types of host rocks may be identified: (1) sodic acid_intermediate_acid volcanic rocks with a porphyritic or porphyroid texture, also called albite_quartz porphyry, which are usually localized in the upper part of an orebody and account for some 20% of the host rocks; (2) sodic intermediate_acid_intermediate_basic volcanic rocks dominated by subhedral lath_shaped and granular pilotaxitic textures (containing a small quantity of phenocrysts), also called andesite_porphyrite, which commonly occur in the middle and middle_lower parts of an orebody and make up about 50% of the host rocks; (3) Al_rich basic volcanic rocks dominated by euhedral_subhedral lath_shaped and granular pilotaxitic textures, also called peraluminous basalt, which are generally located in the lower part and footwall of an orebody and make up around 20% of the host rocks; and (4) Na_rich intermediate_acid _intermediate_basic pyroclastic rocks dominated by tuffaceous and clastic textures, which usually occur in the lower part and footwall of an orebody and occupy appoximately 10% of the host rocks. |
| keywords:petrology, porphyry copper deposit, host rock, Na-and Si-metasomatism, Tuwu-Yandong |
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