西藏冈底斯中东段矽卡岩铜-铅-锌多金属矿床特征及成矿远景分析  

Characteristics and metallogenic potential of skarn copper-lead-zinc polymetallic deposits in central eastern Gangdese

作　　者：佘宏全[1] 丰成友[1] 张德全[1] 潘桂棠[2] 李光明[2] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]成都地质矿产研究所,四川成都610082

出　　处：《矿床地质》2005年第5期508-520,共13页Mineral Deposits

基　　金：973项目(2002CB412609)的资助

摘　　要：冈底斯中东段矽卡岩型铜_铅_锌多金属矿床分为甲马—林周、贡嘎—扎囊—泽当和拉萨—谢通门3个次级矿带或矿集区,区域上呈现出一定的矿化分带,以甲马—林周矿集区为主要分布区。岩矿石的硫、氢、氧、铅同位素特征表明成矿流体和矿质主要为岩浆热液来源。Re_Os同位素测年说明甲马—林周矿集区的矽卡岩成矿集中在中新世15～17Ma的较窄时间段内,与该区斑岩型铜钼矿具有相似的岩浆_构造控矿条件和深部地球动力学背景,属同一成矿系列。而冈底斯南带矽卡岩矿床可能形成于印度—亚洲板块的主碰撞期。冈底斯中东段具有良好的矽卡岩型铜多金属矿成矿地质、地球化学条件,显示有良好的找矿前景。The skam copper-lead-zinc polymetallic deposits are distributed in an EW-striking metallogenic belt some 450 km long and 90 km wide. The metallogenic belt can be divided into three sub-behs, i.e., Lhasa-Xietongmen in the western part of Gandese, Jiama-Linzhou in the northeast and Gongga-Zalang- Zhedang in the south- ern part along the Brahmaputra River, with most of the ore deposits located in Jiama-Linzhou sub-belt. The ore deposits show apparent regional zonal distribution. There exist various kinds of polymetallic deposits, such as iron-copper, copper-lead-zinc-（gold-silver）, copper-molybdenum-lead-zinc, copper-gold deposits, and independent copper, lead, zinc and iron deposits. The ore-bearing strata consist mainly of Jurassic-Cretaceous marine carbonate strata and carbonate-bearing marine volcanic-detrital strata. The ore-controlling stocks are dominated by small granitic stocks or porphyries belonging to calcic alkaline N high-K-calcic alkaline series. Orebodies mainly occur in stock-contact zones and tectonic zones beside stocks. The main ore-controlling structures include interlaminar tectonic zones, stock-contact zones and fracture zones. The ore formation shows notable multistage mineralization characteristics, the copper, lead and zinc sulfides must have been precipitated mainly at the retrograde skam stage, and the favorable temperatures for ore precipitation range from 160 to 380℃. Sulfur, hydrogen and oxygen isotope studies indicate that the ore-forming fluids and materials were mainly derived from magmatic fluids. The Re-Os isochronic ages of ore deposits in Jiama-Linzhou region are concentrated in a narrow range of 15-17Ma, coincident with the stretching period in the crust after the formation of the main collision belt in Tibet plateau. This implies that the formation of skam deposits was related to the partial melting at depth and the fluid concentration resulting from the stretching after Indian-Asia plate collision. The skam deposits and the porphyry copper deposits in this region have s

关 键 词：地质学 矽卡岩矿床 斑岩矿床 铜-铅-锌多金属矿床 矿床特征 成矿作用 冈底斯 西藏 

分 类 号：P618.41[天文地球—矿床学] P618.42[天文地球—地质学]