四川西范坪斑岩铜矿床中锌铜矿的发现及成因意义

The Discovery and Genesis of Zinccopperite in a Porphyry-Copper Deposit in Xifanping,Sichuan Province

西范坪锌铜矿是一种罕见的天然锌铜金属互化物,是锌铜互化物系列中的新变种,发现于四川省盐源县西范坪地区石英二长斑岩中。共生矿物有钾长石、钠更长石、石英、黑云母。伴生矿物为黄铁矿、黄铜矿、斑铜矿等。锌铜矿呈金黄色,均质性,粒度0.1～0.5mm,显微硬度VHN10=190kg mm2。视觉反射率Rvis=67.97%,电子探针分析矿物化学成分为Cu59.15%～62.55%,Zn36.3%～39.85%,晶体化学式为Cu7Zn4。该类矿物多数与造岩矿物共生,形成于高温、还原、缺硫的条件,不同于大多数金属硫化物的形成条件。

Zinccopperite is a rare native alloy mineral discovered in quartz monzoniteprophyry in the Xifanping area, Yanyuan county, Sichuan province. It is a new species of zinccopper alloy mineral found in the porphyrycopper deposit, and the associated minerals include pyrite and chalcophyrite. It is characterized by golden reflection colour and isotropic (isometric), with the grain size ranging from 0.1 to 0.5mm, microhardness VHN10=190 kg/mm2, and reflectance Rvis=67.97%. Electron microprobe (Model JXA733) analysis shows Cu = 59.15%-62.55% and Zn =36.32%-39.85%. The crystallochemical formula is Cu7Zn4. This type of minerals was formed in the environment with high temperature, reduction and sulphur lacking. The majority of this type minerals were paragenetic with rockforming minerals and their forming conditions were different from many metal sulphides also. 