东昆仑祁漫塔格早中生代大陆地壳增生过程中的岩浆活动与成矿作用

发布时间：2018-05-08 05:00

本文选题：地质学 + 大陆增生　；参考：《矿床地质》2017年02期

【摘要】：东昆仑祁漫塔格地区位于青藏高原北缘,为典型的大陆边缘增生造山带,经历了漫长的古生代—早中生代增生造山过程,其中以早中生代岩浆活动与成矿作用最为发育。文章系统总结了区内早中生代侵入岩分布及成因,对与其相关矿床地质、成矿流体特征及成矿物质来源进行分析,进一步探讨了祁漫塔格地区早中生代大陆地壳增生过程中的壳幔混合岩浆活动与成矿作用的关联。研究结果认为,中二叠世—早三叠世以俯冲阶段的侧向增生为主,中-晚三叠世以碰撞-后碰撞阶段的垂向增生为主,与成矿有关的岩浆岩主要为中-晚三叠世石英闪长岩、花岗闪长岩、二长花岗岩、正长花岗岩、花岗斑岩等,以I型、A型花岗岩为主,且多见暗色包体,Sr-Nd-Hf同位素组成表明其源于古陆壳物质的重熔,有地幔物质的参与,由地幔底侵古老陆壳,幔源基性岩浆与壳源花岗质岩浆发生不同程度混合作用而形成。与该时期岩浆活动关系密切的主要为斑岩型铜钼矿床、矽卡岩型铁多金属矿床、层控矽卡岩型铅锌矿床、与碱性花岗岩有关稀有金属矿化等。成矿时代集中于248~210 Ma,成矿流体主要来源于岩浆热液,成矿物质具有壳幔混合来源,区内中-晚三叠世大陆垂向增生过程中的壳-幔岩浆混合作用为区域大规模金属成矿提供大量热能、成矿流体及成矿物质。
[Abstract]:The Qimantage area in East Kunlun, located on the northern margin of the Qinghai-Tibet Plateau, is a typical continental margin accretionary orogenic belt, which has undergone a long period of Paleozoic to early Mesozoic accretion orogeny, in which the early Mesozoic magmatic activity and mineralization are the most developed. In this paper, the distribution and genesis of early Mesozoic intrusive rocks in the area are systematically summarized, and the geology, ore-forming fluid characteristics and source of ore-forming materials are analyzed. The relationship between crust and mantle mixed magma activity and mineralization during the early Mesozoic continental crustal accretion in Qimantage area is further discussed. The results show that the Mesozoic to early Triassic is dominated by lateral accretion in the subduction stage, the mid-late Triassic is dominated by the vertical accretion in the collision-post-collision stage, and the magmatic rocks related to mineralization are mainly intermediate-late Triassic quartz diorite. Granodiorite, monzogranite, syenite, granitic porphyry, etc., I type and A type granite are dominant, and the isotopic composition of dark inclusion body Sr-Nd-Hf indicates that it originated from the remelting of paleocontinental crust material, with the participation of mantle material. It is formed by the mixing of mantle basement magma and crust-derived granitic magma in the ancient continental crust. The related magmatic activities are mainly porphyry copper-molybdenum deposits skarn iron polymetallic deposits stratabound skarn type lead-zinc deposits and mineralization of rare metals related to alkaline granite and so on. The ore-forming age was concentrated at 248 ~ 210 Ma.The ore-forming fluid was mainly derived from magmatic hydrothermal solution, and the ore-forming material came from the mixture of crust and mantle. The crust-mantle magma mixing in the Meso-late Triassic continental vertical accretion provides a large amount of heat energy, ore-forming fluid and ore-forming material for regional large-scale metal mineralization.
【作者单位】：国土资源部岩浆作用成矿与找矿重点实验室中国地质调查局西安地质调查中心;
【基金】：国家自然科学基金青年项目(编号:41102050) 陕西省自然科学基础研究计划项目(编号:2013JM5010) 陕西省科学技术研究发展计划项目(编号:2015KJXX-71) 中国地质调查局地质调查项目(编号:1212011121088;12120115019501;DD20160015;DD20160346);中国地质调查局青年地质英才计划(2013)联合资助
【分类号】：P588.11;P611.11

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