中文摘要:拉诺玛铅锌锑多金属矿床位于西藏昌都盆地，在吉塘镇北约10 km处。矿体赋存在三叠系上统波里拉组（T3b）灰岩的构造破碎带中，是澜沧江沉积岩容矿型铅锌成矿带内的一个重要矿床。该矿床的成矿元素组成与该成矿带内其他铅锌矿床及国内外其他主要沉积岩容矿型铅锌矿床有所不同，以锑铅锌共生组合为特征。矿石成分分析及矿石矿物成分的电子探针分析表明，该矿床铅锑密切共生，且呈纤硫锑铅矿产出。流体包裹体分析结果表明：该矿床形成于中 低温到低温（140～350℃）、中低盐度〔w(NaCleq)为2%～13％〕，以含NaCl为主，包裹体的气相成分以CO2为主，含有CH4、C2H6等短链烃类，成矿流体为NaCl型含烃富CO2流体。热液方解石的碳同位素组成δ13CV-PDB=-3.5‰～+1.8‰，氧同位素组成δ18OV-SMOW=+11‰～+16‰，介于海相碳酸盐岩和与花岗岩有关的热液之间，反映出其来源为深部构造-岩浆活动与海相碳酸盐岩溶解作用的混合。矿石硫化物的硫同位素组成δ34SV-PDB=-1.6‰～+2.6‰，集中在0值附近，反映出硫主要为深部来源。经综合分析认为，该矿床的成矿作用可能与新生代深部构造_岩浆活动有密切关系，其成矿背景与印度板块碰撞作用有关，成矿物质主要来源于与剪切作用有关的构造-岩浆活动，但昌都盆地内沉积地层中的建造水或地下水参与了成矿，部分成矿物质可能来源于三叠系，成矿流体的驱动机制包括上部重力驱动，以及深部构造-岩浆活动热源驱动所形成的大规模成矿流体运动。
中文关键词:地质学 地球化学 澜沧江Pb-Zn成矿带 拉诺玛铅锌锑多金属矿床 昌都盆地 西藏
Abstract:The Lanuoma Pb-Zn-Sb polymetallic deposit is located 10 km north of Jitang in Changdu basin, hosted by carbonate of Triassic Bolila Group (T3b). The ore deposit occurs in an ore district which is considered to be a part of the Sanjiang base-metal ore-forming belt along the Lancang River. It is unique in metallic composition of the ores. Different from the lead-zinc deposits in the Lanping basin and other major sedimentary rock hosted lead-zinc deposits both in China and abroad, the Lanuoma ore deposit is characterized by mineralization of Sb associated with Pb, Zn. Ore composition analysis and electron microprobe analysis of ore minerals show that Sb is closely associated with Pb and occurs as robinsonite. The ore deposit was formed at intermediate-low to epithermal temperatures. Fluid inclusions in hydrothermal quartz and calcite veins are mainly in the two-phase (L+V) state at room temperature and are homogenized to the liquid phase between 140 and 350 ℃. Their salinities 〔w(NaCleq)〕 range from 2% to 10%.Results of bulk analysis of the fluid inclusions show that Na+ and Cl- are most abundant components in liquid phase. CO2 and trace CH4, C2H6 were detected by bulk analysis and laser Raman spectrometry in vapor phase of the fluid inclusions. These data indicate that the ore-forming fluid is NaCl-type, CO2-rich and hydrocarbon-bearing fluid brine. δ13CV-PDB values of hydrothermal calcite range from -3.5‰ to +1.8‰, and δ18OV-SMOW values of hydrothermal calcite range from +11‰ to +16‰, suggesting the characteristics between marine carbonate rocks and granite-related fluids and the mixing of magmatic components with hydrothermal dissolution of marine carbonate. The sulfide minerals have a restricted range of δ34S values from -1.6‰ to +2.6‰ around zero, indicating that the sulfur is of deep crustal derivation. The authors hold that the mineralization was related to Cenozoic magmatism associated with Indo-Asian collision. The sulfur and metals were derived mainly from igneous source or leached from crustal rocks related to tectono-magmatic activity, and partly from the Triassic strata. The fluid-driven mechanism included topography-driven fluid flow in cover sequences and deep magmatic heat source driving for large-scale ore-forming fluid flow.
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基金项目:本文得到国家重点基础研究发展计划（编号：2009CB421005）、中国科学院重要方向项目（编号：KZCX2-YW-O04-08）和国家自然科学基金项目(编号：40973039)的联合资助
引用文本：
陶琰,毕献武,辛忠雷,朱飞霖,廖名扬,李玉帮.2011.西藏昌都地区拉诺玛铅锌锑多金属矿床地质地球化学特征及成因分析[J].矿床地质,30(4):599~615陶琰,毕献武,辛忠雷,朱飞霖,廖名扬,李玉帮.2011.Geology, geochemistry and origin of Lanuoma Pb-Zn-Sb deposit in Changdu area, Tibet[J].Mineral Deposits30(4):599~615
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