【作者】 张刚阳；

【导师】 郑有业；

【作者基本信息】 中国地质大学 ， 矿物学、岩石学、矿床学， 2012， 博士

【摘要】 本论文以藏南金锑成矿带的查拉普金矿、马扎拉金锑矿、车穷卓布锑矿、扎西康铅锌多金属矿为典型矿床,在野外地质调查的基础上,通过详细的成矿期次阶段分析、矿相学观察、流体包裹体研究、矿物H-O-S-Pb同位素分析,锆石U-Pb年代学和含钾矿物Ar-Ar年代学分析、区域成矿规律总结分析,得出以下结论：1、总结了藏南金锑成矿带典型矿床的矿床地质特征和成矿地质条件。查拉普金矿矿体主要受近东西向断裂构造控制,产出蚀变岩型、破碎带型和石英脉型矿石,发育自然金和不可见金,后者主要赋存与毒砂和黄铁矿中。主要发育有石英、绢云母、伊利石、绿泥石等蚀变矿物以及毒砂、黄铁矿等金属矿物。成矿温度在164℃～308℃之间,盐度在2.7wt%Nac1～9.3wt%Nac1之间,形成深度大约为1.1～3.8Km范围,为浅成环境。矿流体具有变质水相似的特征,有地表水的加入。热液蚀变是造成金属沉淀的主要机制,其次为冷却降温和流体混合。马扎拉金锑矿矿体主要受控于地层层间破碎带,产出的矿石类型主要为含金辉锑矿-石英脉。主要发育石英、碳酸盐、绢云母、绿泥石等蚀变矿物以及毒砂、辉锑矿、黄铁矿等金属矿物。金以自然金形式产出为主,极少量以不可见金出现为毒砂、辉锑矿和黄铁矿中。成矿温度在134℃～324℃之间,盐度在0.41wt%Nac1～7.81wt%Nac1之间,形成深度大约为1.1～2.8Km范围,为浅成环境。金属沉淀机制、流体来源与查拉普金矿相似,具有与变质水相似的特征,有地表水的加入。热液蚀变、冷却降温和流体混合是矿质的沉淀机制。车穷卓布锑矿矿体主要受控于近南北向高角度正断层,产出的矿石类型主要为辉锑矿石英脉和辉锑矿方解石脉。主要发育有石英、方解石等蚀变矿物,金属矿物主要为辉锑矿。主要的锑矿化温度在121℃～234.5℃之间,盐度在1.40wt%Nac1～4.65wt%Nac1之间,成矿深度大约为0.6～1.9Km范围,为超浅成环境。成矿流体主要为地表水,显示与建造水混合的趋势。流体混合和冷却降温是造成锑金属沉淀的主要机制。扎西康铅锌多金属矿主要受控于近南北向高角度正断层,产出的矿石类型主要为闪锌矿-铁锰碳酸盐脉、方铅矿-铁锰碳酸盐脉、辉锑矿-石英脉和辰砂-辉锑矿-石英脉。主要发育石英、菱锰矿、方解石、菱铁矿、云母等蚀变矿物,金属矿物主要为闪锌矿、方铅矿、辉锑矿、毒砂、黄铁矿等。主要金属矿化的温度分布在211℃～328℃之间,盐度在0.70wt%Nac1～12.51wt%Nac1之间,成矿深度大约为0.4～1.1Km范围,为超浅成环境。成矿流体主要为建造水,并有与西藏地表水混合的趋势。金属沉淀机制与锑矿相似,主要为流体混合和冷却降温。2、限定了藏南金锑成矿带的成矿和成岩时代。利用锆石U-Pb年代学,确定了沙拉岗锑矿的闪长岩形成于23.6±0.8Ma,间接限定了切割闪长岩的辉锑矿-石英脉的形成时间小于23.6±0.8Ma。利用伊利石Ar-Ar年代学方法,限定了查拉普金矿热液活动的时间大约在20.43Ma。利用锆石U-Pb年代学方法限定了扎西康矿床辉绿岩脉形成于133.1Ma,远早于金锑成矿时间,与区域地层中广泛分布的辉绿岩墙形成时代一致,新特提斯洋晚期大规模扩张的产物。3、根据本文年代学资料,在前人研究基础上,将藏南金锑多金属成矿作用划分为两阶段：(1)同碰撞阶段与韧性剪切相关的金矿,矿体受控于近东西向韧性剪切带及其次级断裂,发育有以含自然金-石英脉为典型特征的矿体,以邦布、马攸木等造山型金矿为代表,形成于59.3Ma～42.0Ma。(2)后碰撞阶段与伸展变形有关的金矿、金锑矿、锑矿和铅锌多金属矿,矿体主要受控于近南北向的高角度正断层和近东西向的层间破碎带,发育有蚀变型金矿体、热液脉状金属矿体,以沙拉岗、车穷卓布、扎西康等为代表,形成于23.6Ma-18.7Mao4、建立了特提斯喜马拉雅金锑多金属控矿构造格架。提出以近东西向的拉孜—邛多江缝合带(北)、绒布生长断层(中)、洛扎生长断层(南)与近SN向的勒金康桑走滑断裂带(西)、下坝走滑断裂带(中)和泽日—洞嘎伸展走滑断裂带(东)围限,构成的羊卓雍错—哲古错—拿日雍错被动大陆边缘裂谷(断陷)盆地周缘的盆山转换部位是成矿有利的地区。金、金锑矿床主要受近东西向拆离构造及其次级构造控制；锑、铅锌多金属矿床主要受近南北向走滑正断系统及其次级构造控制,特别是东西向拆离断裂与南北向走滑正断系统的交汇部位更是寻找锑、铅锌多金属矿的最有利部位。5、在特提斯喜马拉雅划分出三大成矿作用期、三大成矿系列、五大矿床成因类型。三大成矿作用期：(1)被动大陆边缘裂谷(裂陷)喷流(热水)沉积、浊流沉积、有机质富集的同沉积期；(2)大陆边缘弧前增生楔中的动力变质、韧-脆性剪切的同碰撞期；(3)伸展拆离、正断系统及中酸性次火山岩浆热液(包括热泉水)叠加改造的后碰撞期。三大成矿系列：(1)与喷流-沉积-改造有关的AuAs、CuZn、PbZnAg、 PbZnAgMnFe矿床系列；(2)与增生杂岩中与韧-脆性剪切带相关的造山型HgSb、AuSb、AuAs矿床系列；(3)与次火山岩浆热液(包括热泉)有关的Hg→AsSb→AuAg→PbZnAg→PbZn→Cu矿床系列。五大矿床成因类型：(1)喷流沉积-改造型：包括喷流沉积-热泉水改造型(如扎西康、则日铅锌多金属矿)、喷流沉积-次火山岩浆热液改造型(如马扎拉、哲古、姜仓金锑矿)；(2)次火山岩浆热液型(如沙拉岗、得龙锑矿)；(3)热泉型(如车穷卓布、勇日锑矿)；(4)卡林型-类卡林型(如查拉普、熊曲金矿)；(5)造山型(如邦布、洗贡金矿)。6、总结了藏南金锑成矿带的成矿规律和控矿要素,提出特提斯喜马拉雅“四要素”找矿模式。成矿物质主要来源于中生代沉积盆地的黑色岩系,其次为变质基底。成矿流体主要为盆地卤水、下渗的地表水、变质水、岩浆水等流体不同程度的混合。以羊卓雍错盆地为中心,矿床沿区域性近东西向和近南北向断裂带成群分布、分段集中,形成了金矿、金锑矿、锑矿和铅锌多金属矿。同沉积期黑色碳硅泥岩系和中基性脉岩、同碰撞期的韧脆性剪切及动力变质、后碰撞期EW向拆离构造或近SN走滑正断系统、中新世的中酸性次火山岩浆或地表发育的热泉活动遗迹的“四要素”,是特提斯喜马拉雅地区最重要的找矿标志。7、在研究区划分了成矿远景区6个,其中A类远景区2个,分别为马扎拉—扎西康金锑多金属找矿远景区(A1)和洛扎-措美锑成矿远景区(A2)。B类成矿远景区3个,分别为浪卡子金成矿远景区(B1)、沙拉岗-康马锑成矿远景区(B2)和查拉普-三安曲林金成矿远景区(B3)。C类远景区1个,为邦布-白露金成矿远景区(C1)。更多还原

【Abstract】 This thesis, metallogenic model and prospecting potential in Southern Tibet Au-Sb Polymetallic Belt, take the Chalapu Au deposit, Mazhala Au-Sb deposit, Cheqiongzhuobu Sb deposit, and Zhaxikang Pb-Zn polymetallic deposit as representative deposits of Southern Tibet Au-Sb metallogenic belt. The author operate series of field and laboratory work on field geological investigation, detailed mineralization stages, metallogenic structural survey, mineralographical observations, fluid inclusions analysis, mineral H-O-S-Pb isotopic analysis, zircon U-Pb and potassium-bearing mineral Ar-Ar dating geochronology. The detailed conclusions are described as follows:1. This thesis systematically summarized the geological characteristics and metallogenic conditions of the typical deposits in Southern Tibet Au-Sb metallogenic belt.Ore bodies in Chalapu Au deposit are mainly controlled by E-W faults. Three different ore type, alteration type, breccia type and quartz vein type, are exsit in Chalapu Au deposit. The gold appears in native gold and invisible gold minerals, later of which are exist in arsenopyrite and pyrite. The main alteration minerals are quartz, sericite, illite, chlorite, the main metal minerals are arsenopyrite and pyrite. The ore-forming fluid temperature rang from164℃to308℃, with salinities of2.7wt%NaCl-9.3wt%NaCl, The ore-forming depth is about1.1～3.8Km (hypabyssal environment). The characteristic of ore-forming fluid in Chalapu Au deposit is similar with metamorphic water, but added with some earth surface water. Hydrothermal alteration is the key factor to cause metal precipitation, secondly are fluid cooling and fluid mixing.Mazhala Au-Sb deposit is controlled by interlaminar fracture zone. The mainly ore type are quartz (calcite) vein and alteration type. The main alteration minerals are quartz, carbonate, sericite, chlorite; where main metal minerals are arsenopyrite, stibnite, pyrite, etc. gold mainly appears in native gold, only a litter of gold exist in arsenopyrite, stibnite, pyrite as invisible gold. The temperature of ore-forming fluid in Mazhala Au-Sb deposit rang from134℃to324℃, with salinities of0.41wt%NaCl-7.81wt%NaCl, estimated ore-forming depth is about1.1～2.8Km (hypabyssal environment). The mechanism of metal precipitation and ore-forming fluid source are similar with Chalapu deposit. Characteristic of ore-forming fluids are similar with metamorphic water, but mixed with earth surface water. The hydrothermal alteration, cooling and fluid mixing are the main factors to cause mineralization.Cheqiongzhuobu Sb deposit is controlled by S-N high-angle normal faults. The mainly ore types are stibnite quartz vein and stibnite calcite vein. The main alteration minerals in this deposit are quartz and calcite; the main metal mineral is stibnite. The temperature of ore-forming fluid is between121℃and234.5℃, with salinities of1.40wt%NaCl-4.65wt%NaCl. Estimated depth of Sb mineralization is about0.6-1.9Km (ultra-hypabyssal environment). The ore-forming fluids are mainly earth surface water, but appeared trend of mixing with organic water. The cooling and fluid mixing are the main factors for Sb metal deposits.Zhaxikang Pb-Zn polymetallic deposit are controlled by S-N high-angle normal faults. The ore types contain sphalerite-Fe-Mn carbonate vein, galena-Fe-Mn carbonate vein, stibnite quartz vein and cinnabar stibnite quartz vein. The main alteration minerals are quartz, rhodochrosite, calcite, siderite, mica; main metal minerals are sphalerite, galena, stibnite, arsenopyrite and pyrite. The temperature of ore-forming fluid is between211℃and328℃, with salinities of0.70wt%NaCl-12.51wt%NaC. Estimated mineralization depth is about0.4～1.1Km (ultra-hypabyssal environment). The ore-forming fluids are mainly organic water, but mixed with Tibet surface water. The mineralization mechanism is similar with stibnite deposits, which are mainly caused by cooling and fluid mixing.2. Constrains the metallogenic epoch of Southern Tibet Au-Sb metallogenic belt. The diorite in Shalagang Sb deposit is formed at ca.23.6±0.8Ma, constrained by zircon U-Pb geochronology. This data indirectly restrict that mineralization time of stibnite-quartz veins, which cross cut diorite, is younger than23.6±0.8Ma. The hydrothermal activity time of Chalapu Au deposit is ca.20.43Ma, constrained by illite Ar-Ar geochronology. Zircon U-Pb geochronological age of diabase dike in Zhaxikang deposit is133.1Ma, which is consistent with the age of diabase dikes widely distributed in Tethyan Himalayan, indicate that Tethyan Himalaya was in a strong extension tectonic environment.3. Combined with previous study, there are two mineralization stages in Southern Tibet Au-Sb mellogenic zone:(l)Shear-zone related Au deposit in sy-collision stage. The ore-bodies are controlled by shear-zone and secondary faults, charactered with natural gold-quartzs veins. The representative deposits of this stage are Bangbu and Mayoumu Au orogenic deposits, which are formed during59Ma-42Ma.(2) Extention-relared Au, AuSb, Sb and PbZnAg polymetal mineralization in post-collision. The ore bodies are controlled by N-S high angle normal fault and E-W interlayer fragmentized fault belt, charactered with alteration type gold ore and hydrothermal vein type ore. The represented deposits of this stage are Shalagang, Cheqiongzhuobu and Zhaxikang deposits, which are formed during23.6Ma-18.7Ma.4. Tethyan Himalaya metallogenic structures model are established. The basin-orogeny transition district in Yamzho Yum Tso-zhegucuo-Puma Yun Tso passive continent rift basin, which are consisted by E-W striking faults (Lazi-Qiongduojiang suture belt, Rongbu fault, Luozha fault) and N-S striking stike-slip fault belt (Lejingkangsang, xiaba stike-slip fault belt and Zeri-Dongga extension stike-slip fault), are the favorable place for mineralization. The regional E-W structure and its secondary faults controlled the distribution of major Au and Au-Sb deposits; the regional N-S faults mainly controlled the distribution of Sb and Pb-Zn polymetallic deposits. The places, N-S faults interwith E-W faults, are potentional locations for Sb,Pb-Zn polymetallic deposits exploration. 5. Three mineralization stage, three metallogenic series and five genetic deposit type are identified in Tethyan Himalaya. The three mineralization stage are (1) passive margin rift sy-sedimentary stage with organic-rich exhalative sediments and turbidite sediments;(2) Continent margin accretionary wedge sy-collision stage with dynamic metamorphism and ductile-brittle shear;(3) Post-collision stage with extension detachment, normal faults, and intermediate-felsic volcanic magmatic hydrothermal (include hot spring water) superimposition and rework. Three metallogenic series are (1) exhalative-sediment-rework related AuAs, CuZn, PbZnAg, PbZnAgMnFe metallogenic series;(2) orogenic HgSb、AuSb、AuAs metallogenic series related with ductile-brittle shear zone in accretionary complex rock;(3) Sub-volcanic magmatic hydrothermal (hot spring) related Hg→AsSb→AuAg→PbZnAg→PbZn→Cu metallogenic series. Five genetic deposit type are (1) exhalative sediment-rework type: including exhalative sediments-hot spring water superimposition rework type (Zhaxikang Zeri Pb-Zn polymetal mineralization), exhalative sediments-Sub-volcanic magmatic hydrothermal superimposition rework (Mazhala, zhegu, Jiangcang AuSb deposits);(2) Sub-volcanic magmatic hydrothermal type(Shalagang,Delong Sb deposits);(3) hot spring type (Cheqiongzhuobu, Yongri sb deposits);(4)Calin, Calin-ke type (Chalapu Au, Xiongqu Au deposit);(5) orogenic type (Bangbu, Xigong Au deposits).6. The metallogenic regularity, ore-controlling factors and "four factors of prospecting model" are summarized. Ore-forming materials are mainly derived from the black rock formation of Mesozoic sedimentary basins, only a litter comes from regional metamorphic basement. Ore-forming fluids are from different partly mixed basin brine fluid, infiltrated surface water, metamorphic fluid and magma fluid. The Au, Au-Sb, Sb, Pb-Zn polymetallic deposits are distributed as a group and segment concentrate surrounded with Yamzho Yum Tso basin, and along the E-W and N-S regional fault belts. The most important prospecting criterias are the "four factors":sy-sediments black carborndum mudstone suits and mafic dikes; sy-collsion ductile-brittle shear and dynamic metamorphism; post-collision extension detachment or S-N strike slip normal faults; Miocene neutral-acidic volcanic magmatic rock or hot Springs activities.7. The study area are subdivided the into6metallogenic prospective areas.1. two class A prospective area:Mazhala-Zhaxikang Au-Sb polymetallic metallogenic prospective area (A1) and Luozha-Cuomei Sb metallogenic prospective area (A2).2. three class B metallogenic prospects:Langkazi Au metallogenic prospective area (B1), Shalagang-Kangma Sb metallogenic prospective area (B2) and Chalapu-Sananqulin Au metallogenic prospective area (B3).3. one class C prospective area:Bangbu-Bailu Au prospective area (C1).更多还原