中国云南易门式铜矿床的主要类型及成因

系统地概括了易门铜矿田的成矿地质背景及2种矿床类型的地质特征,在此基础上论证了火山热水沉积作用、构造改造作用、岩浆叠加作用、地下热水再造作用与成矿密切相关。易门式铜矿床为"裂谷成矿背景-火山热水沉积-构造改造富集-深源岩浆叠加-地下热水再造"型多因复成矿床,建立了新的成矿模式,为该类矿床深部及外围的找矿预测指明了方向。

Major deposit types and genesis of Yimen-type copper deposits, Yunnan, China.

The Yimen copper deposit is a large-scale copper deposit with exploration indicated the basic reserves and pre-mining reserves of economy of about 0.6 million tonnes with Cu averaging 1.0%. There are two major deposit types in the Yimen copper orefield: one is the volcano-hydrothermal sedimentation-reworking type (the Shishan-type), while the other is the volcano-hydrothermal sedimentation-strong reworking-magmatic superimposition type (the Fengshan-type). On the basis of the geological setting of metallogenesis of the Yimen copper orefield and the geological characterstics of the Yimen-type copper deposits, the relations between volcano-hydrothermal sedimentation, tectonic transformation, magmatic superimposition, underground hot water reworking and metallogenesis is discussed in this paper. It is considered that the ore-forming materials are of diverse sources, and are complex in origin. The homogenization temperatures and salinities of mineral fluid inclusions fall mainly within the two ranges: 110～200 ℃ and 220～320 ℃; 20.5wt% and 4～10 wt% and 12～18 wt%. The δ34S values of minerals (Chalcopyrite, Pyrite, bornite and bismuthinite) vary within the range of - 7.2～-20.0 ‰. The metallogenic model of Yimen-type deposits is the "rift metallogenic setting→volcano-hydrothermal sedimentation→tectonic transformation-enrichment→deep-source magmatic superimposition→underground hot water reworking ". The ore-forming model has been established for the dynamics of tectonic ore-forming processes and the exploration of Yimen-type copper ore deposits.