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大陆碰撞与成矿作用是当代成矿学研究的重要前沿。与板块构造成矿作用研究相比,大陆碰撞造山带的成矿作用研究则明显薄弱。文章以青藏高原主碰撞带为对象,研究了印度—亚洲大陆主碰撞过程与区域成矿作用的耦合关系,并初步建立了主碰撞造山成矿模型。研究表明,印度—亚洲大陆主碰撞始于65Ma,延续至41Ma,形成了以藏南前陆冲断带、冈底斯主碰撞构造_岩浆带和藏北陆内褶皱_逆冲带为特征的青藏高原碰撞造山带主体。伴随陆_陆碰撞,在冈底斯带相继发育①壳源白云母花岗岩_钾质钙碱性花岗岩组合(66～50Ma)、②+εNd花岗岩_辉长岩组合(52～47Ma)和③幔源玄武质次火山岩_辉绿岩脉组合(42Ma),以及大面积分布的巨厚(5000m)的林子宗火山岩系(65～43Ma),反映深部相继发生大陆碰撞和板片陡深俯冲(65～52Ma)→板片断离(52～42Ma)→板片低角度俯冲(<40Ma)等重要过程。在主碰撞期,初步识别出4个重要的成矿事件:①与壳源花岗岩有关的Sn、稀有金属成矿事件,在藏东滇西形成腾冲Sn、稀有金属矿集区;②与壳/幔花岗岩有关的Cu_Au_Mo成矿事件,在冈底斯南缘形成长达百余公里的Cu_Au矿化带;③与碰撞造山有关的剪切带型Au成矿事件,沿雅鲁藏布江缝合带分布,形成具有较大成矿潜力的Au矿化带;④与挤压抬升有关的Cu_Au成矿事件,形成以雄村大型铜金矿为代表的斑岩型/浅成低温复合型Cu_Au矿床。在综合研究基础上,初步建立了大陆主碰撞造山区域成矿模型。
The collision and mineralization in the mainland are important frontiers in the study of mineralization. Compared with the tectonic mineralization of plate tectonics, the research on the metallogenesis of the continental collision orogenic belt is obviously weak. Taking the main collision zone of the Qinghai-Tibet Plateau as an example, this paper studies the coupling relationship between the main collision process and regional mineralization in India-Asia continent, and establishes a primary collision orogenic metallogenic model. The study shows that the main collision in India-Asia continent starts from 65Ma and lasts to 41Ma, and is characterized by the southern Tibet-southern continental belt, the Gangdese main collision structure-magmatic belt and the inland continental fold-thrust belt Qinghai - Tibet Plateau orogenic belt main body. In the Gangdese belt, accompanied by the continental-continental collision, the crustal dolomite granite-potash calc-alkaline granitoid assemblage (66-50Ma), ② + εNd granite-gabbro assemblage (52-47Ma) and ③ mantle (42 Ma) and the Linzizong volcanic series (65 ~ 43 Ma) with a large area of 5000 m, reflecting the occurrence of continental collisions and steep-deep subduction in the deep ~ 52Ma) → plate off (52 ~ 42Ma) → plate low angle subduction (<40Ma) and other important processes. In the main collision period, four important metallogenic events were initially identified: (1) Sn and rare metallogenic events related to shell source granites, forming Tengchong Sn and rare metal ore deposits in western Yunnan; (2) Cu_Au_Mo metallogenic event related to mantle granite, forming a Cu_Au mineralization belt up to 100 km in the southern margin of Gangdese. (3) The shear-zone Au mineralization event related to collision orogeny is distributed along the Brahmaputra suture zone Larger Au mineralization potential; ④ Cu_Au metallogenetic events associated with crustal uplift and the formation of a porphyry-epithermal Cu_Au deposit represented by the Xiongcun large copper-gold deposit. Based on the comprehensive study, a preliminary metallogenic model of the main collision orogen in the mainland has been established.