南秦岭山阳-柞水矿集区构造-岩浆-成矿作用

Tectono-magmatism and metallogeneses of Shanyang-Zhashui ore concentration area in Qinling Orogen

山阳-柞水矿集区是南秦岭成矿带主要矿集区之一。从新元古代到晚侏罗世-早白垩世,山阳-柞水地区经历了洋壳俯冲和陆陆碰撞的构造演化,在演化的不同阶段形成了不同矿化类型、矿化组合的Cu、PbZn、Ag、Fe、Mo、Au矿床。新元古代时期,由于洋壳的俯冲作用,山阳-柞水地区形成了与基性岩有关的钛磁铁矿;泥盆纪-二叠纪时期,古秦岭洋消减形成山阳-柞水弧前盆地的同时,也形成一系列沉积型Fe、Ag、PbZn矿床;三叠纪时期,华北、扬子板块全面碰撞并形成了与碰撞作用密切相关的晚三叠世斑岩型Mo矿和造山型Au矿;晚侏罗世-早白垩世时期,则形成了碰撞后伸展环境下的矽卡岩-斑岩型CuMo-Au矿床。山阳-柞水矿集区内的各种时代和类型的矿床是秦岭造山带不同阶段的构造-岩浆活动的产物,对真实、客观的理解秦岭地区的构造演化具有重要意义。

Shanyang-Zhashui ore concentration area is one important unit of the Qinling metallogenic belt. It experienced oceanic subduction and continental collision during Neoproterozic and Late Jurassic-Early Cretaceous periods,which formed different types of mineralization and ore deposits such as Cu,PbZn,Ag,Fe,Mo and Au in different process of tectonic evolution. The titanomagnetite deposit which is hosted in the mafic rocks was formed by subduction of the Paleo-Qinling Ocean during Neoproterozoic. Continous subduction of the Paleo-Qinling Ocean resulted in formation of Shanyang-Zhahui forearc basin which hosted in sedimentary-type deposits of Fe,Ag and PbZn during Devonian-Permian. From Triassic to Late Jurassic-Early Cretaceous,North China collided with South China and related mineralization also formed during this process,but the Triassic porphyry-skarn type of Mo deposits and orogenic type of Au deposits formed in the collisional environment and Late Jurassic-Early Cretaceous porphyry-skarn type of CuMo-Au deposits formed in a post-collisional extensive environment. These facts indicate that these ore deposits in Shanyang-Zhashui ore concentration area are the products of the tectono-magmatism,corresponding with different stage of tectonic evolution. It is important to objectively understand the evolution the Qinling orogenic belt.