大洋洲斐济群岛的成矿地质背景、矿床类型及成矿期划分

Metallogenic geological setting, deposit types and metallogenic periods in Fiji Islands,Oceania

斐济群岛具有厚而年轻的硅镁质地壳,其成矿作用与构造演化有着密切的联系。斐济群岛的地层主要由新生代海底碎屑型火山岩及相关沉积岩组成。碳酸盐岩和在中—晚中新世一次重要的构造运动中侵入的辉长岩—英云闪长岩质的深成岩也很发育。斐济群岛的矿床类型包括各种块状硫化物型矿床、斑岩型铜金矿、夕卡岩型铜多金属矿、浅成低温热液型金矿、沉积型锰矿、残积矿床、砂矿床等。斐济群岛的成矿期有4个不同的阶段(时期),这些阶段(时期)与构造运动紧密相关,反映了纵贯斐济群岛的各种矿化类型的空间和时间分布特征。

The Fiji platform has a thick, youthful crust of ensimatic origin, and its metallization is related to tectonic evolution. Stratigraphy within the Fiji Islands indicates a history restricted to the Cenozoic, with volcanic rocks, principally submarine fragmental types with related sediments, dominating the succession. There are also carbonate sediments and plutonic rocks ofgabbroic to tonalitic composition which were intruded during an important middle to late Miocene tectonic event. Mineral deposits in Fiji Islands include various types of massive sulfide deposits, porphyry Cu-Au deposits, skarn deposits, epithermal Au deposits, sedimentary manganese deposits, residual deposits and placer deposits. Four distinct stages in the development of Fiji Islands have been identified. These stages are related to changes in tectonic development and are reflected in the spatial land temporal distribution of various styles of mineralization presently found across Fiji Islands.