中文摘要：

＂三江＂的兰坪、昌都、玉树、沱沱河地区发育丰富的沉积岩容矿贱金属矿床,构成一条极具成矿潜力的巨型矿化带。综合分析表明,带内矿床形成于新生代印-亚大陆碰撞环境,发育在大陆碰撞造山带内部的褶皱-逆冲带内,与逆冲和走滑构造控制的新生代盆地相伴。不同矿区均发育逆冲断层,矿体主要赋存于逆冲断层上盘的碳酸盐岩或碎屑岩内,受与逆冲相关的盐底辟、逆冲断裂的次级断裂、热液溶洞、白云岩化、灰岩破碎、矿前溶洞垮塌、与褶皱有关的密集劈理或断裂等构造或岩相变化控制。金属呈现Pb-Zn、Pb-Zn（-Cu-Ag）、Cu-Co、Cu等组合,其中,Pb-Zn矿床主要发育闪锌矿、方铅矿、黄铁矿、±白铁矿、方解石、白云石,一些矿床富硫酸盐矿物和萤石,也常见沥青,矿化以交代和开放空间充填为主;Pb-Zn（-Cu-Ag）矿床主要发育闪锌矿、细/灰硫砷铅矿、方铅矿、黝铜矿、黄铁矿、方解石、白云石,矿化以脉体或热液溶洞内交代/开放空间充填式出现;Cu矿床由石英-方解石/白云石-Cu硫化物（黄铜矿、黝铜矿、斑铜矿、辉铜矿）脉构成。Pb-Zn和Pb-Zn（-Cu-Ag）矿床成矿流体以低温（〈210℃）和高盐度主体[w（Na Cl）〉10%]的盆地卤水为主,脉状Cu矿床成矿流体可能来自富CO2、具相对高温（180~230℃）和低盐度[w（NaCl）〈11%]的变质流体。盆地卤水中硫酸盐遭受细菌还原±有机热还原或仅经历有机热还原,为Pb-Zn和Pb-Zn（-Cu-Ag）矿床提供了还原硫,下伏火山岩和沉积地层中的硫可能是脉状Cu矿床硫的来源,它们的成矿金属物质均来自于上地壳。该带矿床是一套与岩浆活动无关的后生矿床,以世界上已知的矿床类型来划分,金顶、赵发涌、东莫扎抓、莫海拉亨和茶曲帕查矿床等Pb-Zn矿床及白秧坪东矿带的Pb-Zn（-Cu-Ag）矿床可归为类MVT矿床,白秧坪西矿带脉状Pb-Zn（-Cu-Ag）矿床和脉状C

英文摘要：

Significant economic sediment-hosted base metal deposits occur in Lanping,Changdu,Yushu and Tuotuohe areas of Sanjiang region in southwest China.The authors hold that they were formed during Indian-Asian continental collision and developed within the fold-thrust belt combined with thrust and/or strike-slip-related Cenozoic basins in the interior of the collsional zone.Ore bodies are hosted by carbonate and/or clastic rocks as hanging wall of the thrust fault,controlled by thrust-related salt diapir,second-order faults of the thrust fault, syn-ore hydrothermal karst,dolomitization,thrust-related breccias zones in carbonate,pre-ore karst,and fold-related intense cleavages/faults.The metals have Pb＋Zn,Pb＋Zn（＋Cu＋Ag）,Cu＋Co,or Cu associations in individual ore deposits.Sphalerite,galena,pyrite,±marcasite,calcite/dolomite,and bitumen are common in the Pb-Zn deposits whereas sulfates and fluorite are abundant only in some of these ore deposits.The ores exhibit replacement and open-space filling forms.The main minerals in the Pb-Zn（-Cu-Ag） deposits include sphalerite, jordanite,galena,tetrahedrite,pyrite,calcite,and dolomite.They occur in veins or in hydrothermal karst as replacements and open-space fillings.The Cu deposits are composed of quartz ＋ carbonate minerals ＋ Cu sulfides（chalcopyrite,tetrahedrate,bornite and chalcocite） veins.The ore-forming fluids in the Pb-Zn and Pb-Zn（-Cu-Ag） deposits are dominated by basin brines with low temperatures （210℃） and higher salinities [mainly w（NaCl）10%].The ore-forming fluids are characterized by CO2-rich fluids of metamorphic origin having relatively higher temperatures（180～230℃） and lower salinities [w（NaCl）11%）] in the Cu veins.Biogenic sulfate reduction±thermochemical reduction of sulfate by organic matter might have provided reduced sulfur for most Pb-Zn and Pb-Zn（-Cu-Ag） deposits whereas reduced sulfur in the Cu veins probably originated from volcanic rocks and sedimentary rocks.Upper crustal rocks contributed lea