摘要
金顶矿床位于澜沧江大断裂与金沙江-红河大断裂之间,兰坪-思茅裂谷盆地北部。该盆地自中生代以来沉积了近二万米厚的含盐红色碎屑岩。盆地的基底是前寒武系变质岩。金顶矿区下第三系云龙组(Ey)可分为E_(y^a)、E_(y^b)、E_(y^c),其中E_(y^b)、E_(y^c)为含矿地层·厚约380米。含矿地层之上为一套外来的(推覆)中生代地层。矿床呈一穹窿构造,东界为批江断层。主矿体呈层状、似层状,东部发育不规则脉状矿体。主要矿石矿物为方铅矿、闪锌矿,矿床规模达超大型,伴生的黄铁矿及共生的石膏、天青石均达大型矿床规模。本文对形成金顶矿床一系列特殊的成矿背景和成因机理进行论述,建立了矿床的成因模式认为金顶超大型铅锌矿床的形成与喜山期的板块构造活动有关;是在次一级的陆相断陷盆地封闭时期受推覆-滑覆圈闭,以滑塌角砾岩和冲积扇粗碎屑岩为容矿岩石,为深部含矿热卤水与地下水混合而形成的后生层控矿床。矿床的形成又与丰富的有机质、有机硫的产出有关。金顶铅锌矿床成因模式有别于沉积-喷溢型(Sedex)铅锌矿床模式,也有别于密西西比铅锌矿床(MVT)模式。
The Jinding ore deposit is situated between the Lancangjiang and Jinah-sjiang-Honghe large fractures, the northern part of Lanping-Simao rift ba-sin. About 20,000 m of salty red clastic rocks had been deposited in the said basin since the Mesozoic Era. Precambrian metamorphic rocks constituted the basin basement. The Eogene Yunlong Formation(Ey) of Jinding ore area is divisible into Ey^a, Ey^b and Ey^c, in which the Eyb and Ey^c are the ore-bea-ring horizons 380m thick and overlaid by a set of allochthonous(overthrus-ting) Mesozoic strata. The ore deposit displays a dome structure, bounded by the Pijiang fracture eastward. The main orebody shows stratiform and stra-toid structures, some irregular veined ore also developed in the eastern part. The major ore minerals are galena and sphalerite. The ore deposit is superduty in scale, associated pyrite, parAgenetic gypsum and celestine also reach the large-size deposits. This paper discussed a series of specially metallogenic setting and genetic mechanism on the ore deposit formation,and established the genetic model of the deposit, thus considering that the ore deposit formation was related to the plate-tectonic activity in Himalayan period, and that it belongs to an epi-genetic ore deposit which was trapped by the overthrust-sliding bodies during the closed period of the continental secondgrade fault-subsidence basin, to-king the sliding-collapse breccia and coarse clastic rocks of alluvial facies as the ore-hosting rock and formed by the mixture of deep-seated ore-bearing hot brine with groundwater. Its formation was also relavant to the occurre-nce of rich organic matter and organic sulfer. The genetic model of the ore deposit distinguishes from that of the sedimento-upwelling type (Sedex)or Mississippi valley-type ore deposit(MVT).
出处
《云南地质》
1991年第2期145-190,共46页
Yunnan Geology
