ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    西秦岭成矿带古生界控矿特征及有关成矿作用

    Ore-Controlling Features and Related Mineralization Functiones of the Paleozoic in West Qinling

    • 摘要: 西秦岭成矿带下古生界的赋矿地层分布于南带,主要为志留系,次为寒武系;而上古生界的赋矿地层在南带和北带均有分布,主要为泥盆系,次为石炭系—二叠系。其中,寒武系主要赋存后生浅成中–低温热液作用有关金矿(伴生铜、铀、钼、锑、硒等)。志留系赋存同生沉积作用有关钼钒(伴生镍、铀)、磷、石煤、锰和灰岩矿,后生浅成中-低温热液作用有关金、银、锑、汞和铀矿(伴生铜、钼、镍、钒),局部有表生风化淋滤作用有关褐铁矿、铀矿。南带泥盆系赋存同生沉积作用有关煤、白云岩、石膏、铁和磷矿,后生浅成中–低温热液作用有关铁、金、汞和硫铁矿,局部有表生风化淋滤作用有关褐铁矿;北带泥盆系赋存喷流沉积–改造作用有关铅锌矿及铜矿,后生浅成中–低温热液作用有关铁、铜、金、锑和汞矿,局部有表生风化作用有关白铅矿–菱锌矿。南带石炭系—二叠系赋存沉积作用有关灰岩、白云岩,后生浅成中-低温热液作用有关金和汞矿。北带石炭系—二叠系赋存火山沉积–改造作用有关铅锌矿,后生浅成中–低温热液作用有关金和锑矿等。此外,在西秦岭向东昆仑过渡地带,石炭系—二叠系赋存有火山沉积–改造作用有关铜和锡矿。总之,地层控矿基本分两类:①含矿(同生及准同生关系),矿体是地层的组成部分,成矿时代同于含矿地层时代(志留纪、泥盆纪、石炭纪、二叠纪)。②容矿(后生及表生风化关系),矿体不是地层的组成部分,成矿时代明显晚于容矿地层的时代,区内后生浅成中–低温热液作用主要发生在中生代,风化作用主要发生在新生代。沉积–改造型矿床可视为两种控矿类型的叠加。容矿地层是否矿源层,需具体情况具体分析。

       

      Abstract: The lower Paleozoic ore-bearing strata in the western Qinling metallogenic belt are mainly distributed in the southern belt, predominantly consisting of the Silurian system and followed by the Cambrian system; The upper Paleozoic ore-bearing strata are distributed in both the southern and northern belts, primarily composed of the Devonian system, followed by the Carboniferous-Permian system. Among them, the Cambrian system mainly occurs gold deposits (associated copper, uranium, molybdenum, antimony, selenium, etc.) related to epigenetic hypabyssal medium-low temperature hydrothermal function. The Silurian system occurs molybdenum, vanadium (associated with nickel and uranium), phosphorus, stone coal, manganese and limestone minerals related to syngenetic sedimentation function, epigenetic hypabyssal medium-low temperature hydrothermal function in the formation of gold, silver, antimony, mercury and uranium (associated copper, molybdenum, nickel, vanadium), the local has limonite and uranium deposits related to supergene weathering leaching function. The Devonian system in the southern belt occurs coal, dolomite, gypsum, iron, and phosphate deposits related to syngenetic sedimentation function, epigenetic hypabyssal medium-low temperature hydrothermal function in the formation of iron, gold, mercury, and pyrite, the local has limonite related to supergene weathering leaching function. The Devonian system in the northern belt occurs lead-zinc and copper deposits related to Jet sedimentation-transformation function, epigenetic hypabyssal medium-low temperature hydrothermal function in the formation of iron, copper, gold, antimony, and mercury deposits, the local has cerussite and smithsonite related to supergene weathering function. The Carboniferous-Permian system in the southern belt occurs limestone and dolomite deposits related to sedimentation function, epigenetic hypabyssal medium-low temperature hydrothermal function in the formation of gold and mercury deposits. The Carboniferous-Permian system in the northern belt occurs lead-zinc deposits related to volcanic sedimentary-transform function, epigenetic hypabyssal medium-low temperature hydrothermal function in the formation of gold and antimony deposits. Additionally, in the transitional belt from the west Qinling to the east Kunlun, the Carboniferous-Permian system occurs copper and tin deposits related to volcanic sedimentation- transform function. In summary, the ore control by strata in the area can be classified into two categories: ①ore-bearing deposits (syngenetic and quasi-syngenetic relationship), the ore body is an integral part of a stratum, where the mineralization occurred during the same period as the formation of the ore-bearing strata (Silurian, Devonian, Carboniferous, and Permian). ②ore-hosting deposits (epigenetic and supergene weathering relationship), the ore body is not part of the formation, where the mineralization occurred significantly later than the formation of the ore-hosting strata, epigenetic medium-low temperature hydrothermal function primarily occurred during the Mesozoic era, while weathering function mainly occurred during the Cenozoic era. Sedimentary-transformation type ore deposits can be considered as the overlapping of these two types of ore controls. The identification of whether the ore-hosting strata act as ore source layer depends on specific geological circumstances and requires further analysis.

       

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