江南造山带钨锡稀有金属矿床成矿作用特征

江南造山带是世界上重要的钨锡稀有金属成矿带之一，发育矽卡岩型钨/锡矿、细脉浸染型钨矿、石英脉型黑钨矿/白钨矿、电气石-石英脉型锡矿、云英岩型钨/锡矿和花岗岩-伟晶岩型铌钽矿床，成矿时代包括新元古代、加里东期、印支期和燕山期。依据成矿元素组合，可将成矿花岗岩划分为W-Mo、W、Sn和Nb-Ta花岗岩，其演化程度和地球化学特征显示出明显差异，铌钽矿化发生在极端分异的钠长石花岗岩中。不同时代、不同类型的成矿花岗岩可能来自不同源区的部分熔融，江南造山带可能存在多个稀有金属富集的源区。成矿物质和成矿流体主要源自花岗质岩浆，岩浆分异演化促进了成矿元素在熔体中的富集。铌钽矿主要为岩浆成因，叠加热液矿化，钨锡矿主要通过流体充填和交代作用形成。

Metallogenic Characteristics of Tungsten,Tin, and Rare Metal Deposits in the Jiangnan Orogenic Belt

The Jiangnan Orogenic Belt is an important tungsten, tin, and rare metal metallogenic belt in the world. Skarn tungsten-tin deposits, veinlet-disseminated tungsten deposits, quartz-vein wolframite/scheelite deposits, tourmaline-quartz vein tin deposits, greisen tungsten-tin deposits, and granite-pegmatite niobium-tantalum deposits are developed in this belt. Four metallogenic epochs including Neoproterozoic, Caledonian, Indosinian, and Yanshanian have been identified. The ore-bearing granites can be divided into W-Mo, W, Sn, and Nb-Ta granites based on the metallogenic element assemblages, and their evolution degree and geochemical characteristics show significant differences. Nb-Ta mineralization occurs in the extremely differentiated albite granite. The ore-bearing granites with different ages and types are likely to have been derived from partial melting of sources. The ore-forming materials and fluids mainly originate from the granitic melts, where the magmatic fractionation facilitates the enrichment of ore elements in the melts. The Nb-Ta deposits are primarily of magmatic origin and subordinately overprinted by hydrothermal mineralization, while the W and Sn deposits are dominantly formed through fluid filling and metasomatism.