湖北大冶铜山口铜(钼)矿床中钨矿化特征及其地质意义

Characteristics of Tungsten Mineralization from the Tongshankou Skarn-Porphyry Cu(Mo) Deposit in Daye,Hubei Province,and Its Geological Implications

为了查明鄂东矿集区内铜山口矽卡岩-斑岩型铜(钼)矿床中钨矿化作用的地质特征.对该矿床中的钨矿(化)体开展了系统的矿床地质特征、岩石学和矿物学研究,并探讨基底对区内钨矿在空间上分布的影响.钨矿体主要产出于花岗闪长斑岩与碳酸盐岩地层的接触部位及其附近,其产状受接触面形态的控制;钨既可形成独立的钨矿体,也可作为铜和钼矿体的伴生组分;钨矿物主要为含Mo的白钨矿.铜山口矿床中的钨矿化与矽卡岩化有着密切的时间、空间和成因联系,具有典型的氧化性矽卡岩型钨矿特征,钨和铜矿化是同一岩浆-热液事件不同阶段的产物,但钨矿体的产出位置比铜矿化相对更深;鄂东矿集区南部的钨矿化岩体具有很多相似性,他们很可能在一定程度上受富含铜和钨的江南式基底控制,江南式和董岭式基底在鄂东矿集区的结合部位可能位于阳新岩体附近.

The Tongshankou deposit is a typical skarn-porphyry Cu(Mo)deposit in the East Hubei Province,thick tungsten ore bodies have been discovered in deep part of this deposit recently.In this paper,systematic researches on geological characteristics,petrology,and mineralogy were carried out on tungsten mineralization from the Tongshankou deposit.It is found that tungsten ore bodies were mainly produced at or near the contact zone between sedimentary rocks and granodioritic porphyry.Therefore,their occurrences are controlled by the shape of contact surface.Tungsten can be produced either as a separate tungsten ore body or as a byproduct element in Cu and Mo ore bodies.Scheelite is the mainly tungsten-bearing mineral,and is characterized by a significant enrichment of Mo.Tungsten mineralization process of the Tongshankou deposit is temporally,spatially and genetically associated with skarn alteration,and these features are consistent with those of oxidized W skarns.Tungsten and Cu mineralization are the product of different stages from the same magmatic-hydrothermal process,but the location of W ore bodies are relatively deeper than that of Cu.The Tongshankou porphyry stock shears a lot of similarities with stocks associ-ated with W mineralization in East Hubei Province,suggesting that they were probably partly controlled by Cu and W fertile Jiangnan basement,and the connect part of Jiangnan and Dongling basement under the East Hubei Province probably located nearby the Yangxinpluton.