三江特提斯叠加成矿作用样式及过程

Style and process of the superimposed mineralization in the Sanjiang Tethys

三江地区经历了特提斯洋的多期洋-陆俯冲和新生代以来的陆-陆碰撞;成矿主要集中在大洋生长与俯冲造山阶段以及碰撞造山主碰撞向晚碰撞的转换阶段,控制了区域喜马拉雅期斑岩型铜金矿带、沉积岩容矿型铅锌多金属矿带与造山型金矿带等。在不同时期构造环境作用下,在矿田与矿床范围内形成了复杂多样的叠加成矿作用。叠加成矿作用可划分为3种类型及9种方式:(1)VMS-岩浆热液叠加型。包括喜马拉雅期岩浆热液型矿体叠加海西期-燕山期"VMS型"矿体(老厂式Pb-Zn-Mo矿床和鲁春式Cu-Pb-Zn矿床),印支/燕山期岩浆热液型矿体叠加海西期VMS型矿体的羊拉式Cu-Mo-Pb-Zn矿床;(2)沉积-热液叠加型。包括喜马拉雅期岩浆热液型矿体叠加燕山期沉积矿源层的白秧坪式Cu-Pb-Zn矿床,喜马拉雅期建造热液型Ge矿体叠加沉积煤层的大寨/中寨式Ge矿床,燕山期岩浆热液叠加加里东期分水岭式Fe-Cu矿床;(3)多期热液叠加型。主要为喜马拉雅期与印支期两期叠加成矿作用的老王寨床式Au矿床,燕山期叠加印支期普朗-红山式Cu矿床,喜马拉雅期多期次叠加的金满Cu矿床。叠加成矿作用增加矿床的资源储量,丰富了矿种类型;但是现在仅有部分年代学与矿田-矿床尺度地质现象的某些证据,叠加矿床的矿体-矿石结构特征、形成条件与地球化学及矿物学约束仍有待于进一步研究。

The Sanjiang area in China has experienced the multi-episodes of ocean-continent subductions in the Tethys Period and the continent-continent collision in Cenozoic;various ore deposits formed in the ocean growth and subduction environment,and they are also situated in the transition time from the main collision to late collision stages,the Cenozoic collision induce the formation of the porphyry copper-gold belt,the lead-zinc deposits hosed in sedimentary rocks as well as the orogenic belt.The multiple episodes of metallogenesis located in the different time and tectonic background occurred in one orefield or ore deposit,causing various types of superposed deposits.These deposits can be categorized into three types and further into nine subtypes,that is：（Type 1） superposition of magmatic hydrothermal deposit on the previous VMS deposit,including subtype of Himalayan hydrothermal superposing on the Hercynian-Yanshanian VMS deposit,represented by Laochang Pb-Zn-Mo deposit and Luchun Cu-Pb-Zn deposit,that of IndosinianYanshanian hydrothermal upon the Hercynian VMS deposit,e.g.,Yangla deposit;（Type 2） superposition of magmatic hydrothermal deposit on the previous sedimentary deposit,comprising the subtype of Himalayan hydrothermal superposing on the primary Yanshanian metal-enriched strata,such as Baoyangping Cu-Pb-Zn deposit,that of the Himalayan sedimentary Ge-bearing hydrothermal absorbed by the Miocene coal seam（Dazhai and Zhongzhai Ge deposit）,and that of the Yanshanian hydrothermal superposing the Caledonian metamorphic Fe-bearing horizon（Fenshuiling Fe-Cu deposit） ;（Type 3） superposition of between multiple episodes of magmatic hydrothermal deposit,for instance between Himalayan hydrothermal and the Indosinian one（Laowangzhai gold deposit）,between the Yanshanian upon the Indosinian（Pulang-Hongshan Cu deposit） and between the different Himalayan hydrothermal（Jinman Cu deposit）.The superstition increased the metal types,reserve quantity,economic value of the deposits,yet it was mainly supported by chronological data and general phenomena in deposit and orefield scale,the detailed formation conditions,spatial orebodies and ore structure and the geochemical and mineralogical evidences are still necessary for further study.