研究生知识库

位于中国西南部、扬子地台西缘的川滇黔铅锌矿集区含有400多个铅锌矿床（矿化点），这些矿床总共含有大约200Mt铅锌矿石，是我国重要的铅锌生产基地之一。这些铅锌矿床赋存在震旦系至二叠系碳酸盐岩地层中，矿体受断层或者断裂控制明显，空间分布上与峨眉山溢流玄武岩（～260Ma）分布关系密切。为了更好的阐明该地区铅锌矿床的成矿物质来源、含矿流体的运移路径及其与峨眉山玄武岩的关系（峨眉山玄武岩是否为铅锌矿床提供成矿物质），本文在前人工作的基础上，在川滇地区选取了5个具有代表性的铅锌矿床，分别为：四川天宝山铅锌矿床、四川大梁子铅锌矿床、云南富盛铅锌矿床、云南金沙厂铅锌矿床、云南茂租铅锌矿床。其中，天宝山、大梁子、茂租和金沙厂铅锌矿床赋矿围岩主要为上震旦统灯影组（Z2d）白云岩，富盛铅锌矿床赋矿围岩为下二叠统茅口组（P1m）白云岩。从这五个铅锌矿床中选取了不同类型的铅锌矿石，且从中挑选了闪锌矿、方铅矿、重晶石单矿物，并对闪锌矿进行了S-Pb-Zn-Cd同位素分析，方铅矿、重晶石进行了S同位素分析；此外，对矿床附近的峨眉山玄武岩进行了选择性取样，选择代表性样品进行了主微量元素、Pb-Zn同位素分析。所得到的主要结论如下：S同位素数据显示，所研究矿床中富盛、大梁子、茂租铅锌矿床硫化物（闪锌矿、方铅矿）具有相似的δ34SVCDT值（n，平均值±1σ；n表示样品数量，1σ表示n个样品的标准偏差），变化范围为+5.9‰～+15.9‰（n=48，+13.4‰ ± 2.1‰）；而天宝山铅锌矿床硫化物（闪锌矿、方铅矿）δ34SVCDT值变化范围较窄为+2.2‰～+5.4‰（n=5，+4.0‰ ± 1.3‰）；相比之下，金沙厂铅锌矿床硫化物（闪锌矿、方铅矿）δ34SVCDT值则处于以上两者之间，为+3.0‰～+12.6‰（n=17，+6.3‰ ± 2.8‰），且金沙厂重晶石δ34SVCDT值为+20.8‰～+32.6‰（n=2，+26.7‰ ± 8.4‰）。因此，本文认为富盛、大梁子、茂租铅锌矿床的硫主要来源于寒武系-三叠系沉积地层中蒸发岩或者海水硫酸盐的热化学还原作用；天宝山铅锌矿床的硫主要来源于震旦系灯影组地层下的中-新元古代褶皱基底；金沙厂铅锌矿床的硫具有混合来源，即褶皱基底、与硫化物共存的硫酸盐矿物。闪锌矿Pb同位素数据显示，所研究矿床中天宝山和富盛铅锌矿床具有相似的Pb同位素分布范围，206Pb/204Pb、207Pb/204Pb、208Pb/204Pb值变化范围为：18.415～18.608、15.689～15.727、38.563～38.771；大梁子和茂租铅锌矿床Pb同位素分布范围较一致，206Pb/204Pb、207Pb/204Pb、208Pb/204Pb值变化范围分别在18.211～20.259、15.676～15.840、38.407～40.466之间；而金沙厂铅锌矿床较其他矿床富含发射性Pb同位素，为20.609～21.183、15.852～15.898、40.768～41.442。峨眉山玄武岩样品的Pb同位素比值(206Pb/204Pb)204Ma、(207Pb/204Pb)204Ma、(208Pb/204Pb)204Ma范围分别为：17.975-18.648、15.594-15.680、38.102-38.969。通过和各地层Pb同位素值比较，本文认为天宝山、富盛、大梁子、茂租铅锌矿床的铅主要来源于上震旦统、泥盆系-下二叠统沉积地层，少部分来源于元古代基地地层；金沙厂铅锌矿床富含放射性成因铅，主要来源于寒武系地层，不排除有元古代基地地层铅的加入；由于二叠系峨眉山玄武岩和所研究矿床铅同位素的组成范围不同，并且与所研究铅锌矿床形成有关的峨眉山玄武岩大规模热液蚀变尚未被发现，因此峨眉山玄武岩不太可能为所研究矿床提供铅。Zn同位素数据显示，天宝山、富盛、大梁子、茂租、金沙厂铅锌矿床的闪锌矿的δ66Zn值变化范围分别为：+0.23‰～+0.26‰（n=3，+0.24‰ ± 0.01‰）、+0.09‰～+0.33‰（n=8，+0.23‰ ± 0.08‰）、?0.21‰～+0.22‰（n=17，?0.01‰ ± 0.13‰）、?0.49‰～?0.10‰（n=6，?0.22‰ ± 0.15‰）、?0.05‰～+0.16‰（n=11，+0.05‰ ± 0.06‰）；研究区峨眉山玄武岩δ66Zn值总体变化范围为+0.28‰～+0.34‰（n=13，+0.31‰ ± 0.02‰），与铅锌矿床的Zn同位素相比，δ66Zn值大且变化范围小。通过和各地质单元Zn同位素值比较，本文认为所研究铅锌矿床的锌主要来源于震旦系-下二叠统地层沉积岩，但不排除天宝山铅锌矿床有少部分锌来源于元古代褶皱基底，峨眉山玄武岩为所研究矿床提供Zn的可能性不大。Cd同位素数据显示，天宝山、富盛、大梁子、茂租、金沙厂铅锌矿床的闪锌矿的δ114Cd值变化范围分别为：+0.25‰～+0.29‰（n=3，+0.28‰ ± 0.02‰）、+0.07‰～+0.53‰（n=8，+0.40‰ ± 0.17‰）、?0.10‰～+0.44‰（n=17，+0.11‰ ± 0.13‰）、?0.05‰～+0.10‰（n=6，+0.05‰ ± 0.06‰）、+0.08‰～+0.22‰（n=11，+0.16‰ ± 0.05‰）。所研究矿床同位素数据在图1/Cd–δ114Cd和图Zn/Cd–δ114Cd中显示出与MVT铅锌矿床相同的特征。由于闪锌矿中的Zn同位素与Cd同位素具有相似的分馏机制，从茂租铅锌矿床?→大梁子铅锌矿床?→金沙厂铅锌矿床?→天宝山铅锌矿床，δ66Zn值和δ114Cd值逐渐增大。由于这四个矿床的赋矿围岩均属于上震旦统灯影组地层，所以假设这四个矿床的成矿流体来源于同一套热液流体系统，那么根据Zn和Cd同位素的分馏机制，随着含矿流体的迁移和矿石的沉淀，后期流体会越来越富集锌和镉的重同位素。因此结合所研究矿床的古海拔高度、相对地理位置及区域地质特征，含矿流体的运移路径很可能是先流经茂租铅锌矿床，然后沿着小江断裂、安宁河断裂及其次级断裂，分别运移至大梁子铅锌矿床、金沙厂铅锌矿床和天宝山铅锌矿床。因此，Zn和Cd同位素可以很好的示踪成矿流体的运移路径，指示隐伏矿体的潜在位置。结合区域、矿床地质特征与S、Pb、Zn、Cd同位素特征及其相关性，我们推测所研究矿床的成矿过程如下：由于印支期的造山运动，以及三叠纪晚期研究区附近的印支地块与华南地块的缝合，导致在川滇黔成矿三角区外围形成一系列逆冲断裂和前陆盆地。在前陆盆地的形成过程中，海水或者蒸发卤水逐渐演化为盆地卤水。盆地卤水在三叠纪晚期造山运动的影响下，因重力和地势驱动力的作用产生了大规模的运移。由于盆地卤水中含有大量的容易萃取金属阳离子的络阴离子（主要为氯离子），因此盆地卤水在运移过程中会萃取地层中（震旦系-二叠系地层沉积岩、元古代褶皱基底）的金属物质而逐渐演化为富金属流体。另一方面，地层中的蒸发岩或者海水硫酸盐则因为热化学还原作用（TSR）逐渐演化为富还原硫流体。而碳酸盐岩地层由于盆地卤水的溶蚀作用或者其他物理化学作用产生了一系列的开放空间，而开放空间则有利于流体的汇集和存储。当富金属流体沿着断层或者断裂通道遇到富还原硫流体时，会在开放空间中汇集、反应而形成矿石、矿体。因此，富金属流体与富还原硫流体的混合是矿石沉淀和铅锌矿床形成的主要机制。

The Sichuan–Yunnan–Guizhou (SYG) Pb–Zn metallogenic province in the western Yangtze Block, southwest China, contains more than 400 carbonate–hosted Pb–Zn deposits (mineralized spot), with about 200 million tons of Pb–Zn ores, and it is one of the important lead and zinc production bases in China. These deposits are hosted in Sinian to Permian carbonate rocks, structurally controlled by thrust fault–fold structures and spatially associated with the Emeishan flood basalts (~ 260 Ma). In order to elucidate the source of metals, the pathway of their ore–forming fluids and whether the Emeishan flood basalts provide metallogenic materials for the Pb–Zn deposits, five representative carbonate-hosted Pb-Zn deposits within different stratigraphic sequences, including the Tianbaoshan, Fusheng, Maozu, Jinshachang and Daliangzi deposits in the southwestern part of the SYG Pb–Zn metallogenic province are selected. Different types of Pb–Zn ores were selected in these five deposits, from which sphalerite, galena and barite separates were selected. S–Pb–Zn–Cd isotopes was systematic investigated for sphalerite and S isotope was investigated for galena and barite. In addition, sampling was carried out on the Emeishan flood basalt which near the deposits, the main elements, trace elements, and Pb-Zn isotopic analysis were performed on representative basalt samples. The host rock of Tianbaoshan, Daliangzi, Maozu and Jinshachang deposit are mainly dolomite of upper Sinian Dengying Formaion (Z2d), while Fusheng deposit is dolomite of middle Permian Maokou Formation (P2m). The main conclusions are as follows:S isotope data show that the sulfide (sphalerite, galena) in Fusheng, Daliangzi and Maozu Pb–Zn deposits has a similar value of 34SVCDT (n, mean ± 1σ; n is the number of samples, 1σ is the standard deviation of values for n sample), with a variation range of +5.9‰ to +15.9‰ (n=48, +13.4‰ ± 2.1‰); While in Tianbaoshan Pb–Zn deposit, the smaller range of the 34SVCDT value is +2.2‰ to +5.4‰ (n=5, +4.0‰ ± 1.3‰); The 34SVCDT value of the Jinshachang Pb–Zn deposit (sphalerite and galena) is between the above two, which is +3.0‰ to +12.6‰ (n=17, +6.3‰ ± 2.8‰), and the 34SVCDT value of the barite in Jinshachang is +20.8‰ to +32.6‰ (n=2, +26.7‰ ± 8.4‰). In conclusion, it appears that S in the Fusheng, Daliangzi, and Maozu deposits is derived mainly from evaporates or seawater sulfates in Cambrian–Triassic sedimentary strata; S in the Tianbaoshan deposit originates mainly from the Meso–Neoproterozoic folded basement beneath the Dengying Formation; and S in the Jinshachang deposit may be derived from both folded basement and sulfates coexisting with sulfides.Pb isotope data of sphalerite show that the Pb isotope distribution ranges of the Tianbaoshan and Fusheng Pb–Zn deposit are similar. The ranges of Pb isotope values of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb are 18.415-18.608, 15.689-15.727 and 38.563-38.771; The Pb isotope ranges of the Daliangzi and Maozu Pb–Zn deposit are relatively consistent, and the ranges of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values are 18.211-20.259, 15.676-15.840 and 38.407-40.466; Compared with other deposits, the Jinshachang Pb–Zn deposit is rich in radiogenic Pb isotopes, which are 20.609-21.183, 15.852-15.898, 40.768-41.442, respectively. The Pb isotope ratios (206Pb/204Pb)204Ma, (207Pb/204Pb)204Ma and (208Pb/204Pb)204Ma of Emeishan flood basalt samples are 17.975-18.648, 15.594-15.680 and 38.102-38.969, respectively. Based on the comparison of Pb isotope values with other stratas, this paper holds that the lead of the Tianbaoshan, Fusheng, Daliangzi and Maozu deposit mainly came from upper Sinian, Devonian to Lower Permian sedimentary rocks and the Proterozoic base strata, whereas lead isotope of the Jinshachang deposit is more radiogenic than the other deposits which most likely sourced from the Cambrian sedimentary rocks and the Proterozoic folded basement. In addition, the Permian Emeishan flood basalt and the studied deposit have different ranges of Pb isotope composition, and the large-scale hydrothermal alteration of Emeishan flood basalt associated with the formation of the studied Pb-Zn deposit has not been discovered, so Emeishan flood basalt was likely not provided lead for the studied Pb–Zn deposits. According to the Zn isotope data, sphalerite separates from the Tianbaoshan, Fusheng, Daliangzi, Maozu and Jinshachang deposits display δ66Zn values with ranges of +0.23‰ to +0.26‰ (n=3, +0.24‰ ± 0.01‰), +0.09‰ to +0.33‰ (n=8, +0.23‰ ± 0.08‰), ?0.21‰ to +0.22‰ (n=17, ?0.01‰ ± 0.13‰), ?0.49‰ to ?0.10‰ (n=6, ?0.22‰ ± 0.15‰), ?0.05‰ to +0.16‰ (n=11, +0.05‰ ± 0.06‰), respectively. The range of δ66Zn value of Emeishan flood basalt in the studied area is +0.28‰ to +0.34‰ (n=13, +0.31‰ ± 0.02‰), which is larger than the δ66Zn value of the studied Pb-Zn deposits. By comparing with the Zn isotope values of other stratigraphic units, this paper believes that the source of zinc in the studied Pb-Zn deposit mainly derived from Sinian to Lower Permian sedimentary rocks, but it cannot be excluded that a small part of zinc of Tianbaoshan deposit derived from the Proterozoic folded basement, and the Emeishan flood basalt is unlikely to provide Zn for the studied deposit. Sphalerite separates from the Tianbaoshan, Fusheng, Daliangzi, Maozu and Jinshachang deposits exhibit δ114/110Cd values ranging from +0.25‰ to +0.29‰ (n=3, +0.28‰ ± 0.02‰), +0.07‰ to +0.53‰ (n=8, +0.40‰ ± 0.17‰), ?0.10‰ to +0.44‰ (n=17, +0.11‰ ± 0.13‰), ?0.05‰ to +0.10‰ (n=6, +0.05‰ ± 0.06‰), +0.08‰ to +0.22‰ (n=11, +0.16‰ ± 0.05‰), respectively. The isotopic data of the studied deposits show the same characteristics as the MVT-type Pb-Zn deposit in figure 1/Cd–114Cd and Zn/Cd–114Cd.Cd isotope values of sphalerite share a similar evolution trend with their Zn isotope values display that Zn and Cd isotope composition of sphalerite have similar isotope fractionation mechanism. Furthermore, the Zn and Cd isotope values evolve toward isotopically heavier gradually from Maozu to Daliangzi, Jinshachang and Tianbaoshan, since the host rocks of these four deposits are all Dengying Formation of Upper Sinian, if assumed that the ore-bearing fluid of these four deposits came from the same hydrothermal fluid system, with the migration of fluid and the precipitation of minerals, the ore-bearing fluid would be enriched with more and more heavy isotopes of zinc and cadmium. Combining the geographical position and the geology of these four deposits, the pathways of ore-forming fluids were most likely started from Maozu, along Xiaojiang fault belt, Anninghe fault belt and their branch faults migrated to Daliangzi, Jinshachang and Tianbaoshan, respectively. Thus, Zn and Cd isotopes are good tools in tracing the pathway of ore-forming fluids in the studied Pb-Zn deposits, isotopically heavy Zn and Cd probably can be a geochemical halo in detecting remotely orebodies in a large hydrothermal orebody.Combined with regional, ore deposit geological characteristics and the S, Pb, Zn, Cd isotopes values and correlation, we infer that the metallogenic processes involved in the studied Pb–Zn deposits are as follows. Tectonic events related to the Indosinian Orogeny and post-Late Triassic completion of suturing between the Indochina and South China blocks around the study area led to the development of a series of thrust belts and foreland basins on the periphery of the SYG triangle. During diagenesis in these foreland basins, basinal brines formed from seawater or evaporative brines buried with sediments. Orogenesis during the Late Triassic contributed to long-distance migration and accumulation of basin brines, driven by gravity and topography. Evaporative brines and dissolved halite provided the chloride for metal complexation, while clastic basinal sediments and folded basement provided Zn, Pb, Fe, and other ore-forming metals. The basin brines then migrated along major faults and associated fracture zones or karst systems into reactive carbonates, finally accumulating in different open areas. During this migration, the basin brines evolved into metal-bearing fluids through the extraction of ore-forming metals from upper Sinian and Devonian to lower Permian sedimentary rocks or Proterozoic folded basement, while evaporative brines in host strata evolved into reduced S-bearing fluids through TSR. Faults provided a connection for the mixing of metal-bearing and reduced-S-bearing fluids, leading to precipitation of ore minerals and formation of deposits. In conclution, the mixture of metal-bearing fluids and reduced-S-bearing fluids is the main mechanism of ore precipitation and the formation of Pb-Zn deposit.Fusheng deposit is dolomite of lower Permian Maokou Formation (P1m). The main conclusions are as follows:S isotope data show that the sulfide (sphalerite, galena) in Fusheng, Daliangzi and Maozu Pb–Zn deposits has a similar value of 34SVCDT (n, mean ± 1σ; n is the number of samples, 1σ is the standard deviation of values for n sample), with a variation range of +5.9‰ to +15.9‰ (n=48, +13.4‰ ± 2.1‰); While in Tianbaoshan Pb–Zn deposit, the smaller range of the 34SVCDT value is +2.2‰ to +5.4‰ (n=5, +4.0‰ ± 1.3‰); The 34SVCDT value of the Jinshachang Pb–Zn deposit (sphalerite and galena) is between the above two, which is +3.0‰ to +12.6‰ (n=17, +6.3‰ ± 2.8‰), and the 34SVCDT value of the barite in Jinshachang is +20.8‰ to +32.6‰ (n=2, +26.7‰ ± 8.4‰). In conclusion, it appears that S in the Fusheng, Daliangzi, and Maozu deposits is derived mainly from evaporates or seawater sulfates in Cambrian–Triassic sedimentary strata; S in the Tianbaoshan deposit originates mainly from the Meso–Neoproterozoic folded basement beneath the Dengying Formation; and S in the Jinshachang deposit may be derived from both folded basement and sulfates coexisting with sulfides.Pb isotope data of sphalerite show that the Pb isotope distribution ranges of the Tianbaoshan and Fusheng Pb–Zn deposit are similar. The ranges of Pb isotope values of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb are 18.415-18.608, 15.689-15.727 and 38.563-38.771; The Pb isotope ranges of the Daliangzi and Maozu Pb–Zn deposit are relatively consistent, and the ranges of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values are 18.211-20.259, 15.676-15.840 and 38.407-40.466; Compared with other deposits, the Jinshachang Pb–Zn deposit is rich in radiogenic Pb isotopes, which are 20.609-21.183, 15.852-15.898, 40.768-41.442, respectively. The Pb isotope ratios (206Pb/204Pb)204Ma, (207Pb/204Pb)204Ma and (208Pb/204Pb)204Ma of Emeishan flood basalt samples are 17.975-18.648, 15.594-15.680 and 38.102-38.969, respectively. Based on the comparison of Pb isotope values with other stratas, this paper holds that the lead of the Tianbaoshan, Fusheng, Daliangzi and Maozu deposit mainly came from upper Sinian, Devonian to Lower Permian sedimentary rocks and the Proterozoic base strata, whereas lead isotope of the Jinshachang deposit is more radiogenic than the other deposits which most likely sourced from the Cambrian sedimentary rocks and the Proterozoic folded basement. In addition, the Permian Emeishan flood basalt and the studied deposit have different ranges of Pb isotope composition, and the large-scale hydrothermal alteration of Emeishan flood basalt associated with the formation of the studied Pb-Zn deposit has not been discovered, so Emeishan flood basalt was likely not provided lead for the studied Pb–Zn deposits. According to the Zn isotope data, sphalerite separates from the Tianbaoshan, Fusheng, Daliangzi, Maozu and Jinshachang deposits display δ66Zn values with ranges of +0.23‰ to +0.26‰ (n=3, +0.24‰ ± 0.01‰), +0.09‰ to +0.33‰ (n=8, +0.23‰ ± 0.08‰), ?0.21‰ to +0.22‰ (n=17, ?0.01‰ ± 0.13‰), ?0.49‰ to ?0.10‰ (n=6, ?0.22‰ ± 0.15‰), ?0.05‰ to +0.16‰ (n=11, +0.05‰ ± 0.06‰), respectively. The range of δ66Zn value of Emeishan flood basalt in the studied area is +0.28‰ to +0.34‰ (n=13, +0.31‰ ± 0.02‰), which is larger than the δ66Zn value of the studied Pb-Zn deposits. By comparing with the Zn isotope values of other stratigraphic units, this paper believes that the source of zinc in the studied Pb-Zn deposit mainly derived from Sinian to Lower Permian sedimentary rocks, but it cannot be excluded that a small part of zinc of Tianbaoshan deposit derived from the Proterozoic folded basement, and the Emeishan flood basalt is unlikely to provide Zn for the studied deposit. Sphalerite separates from the Tianbaoshan, Fusheng, Daliangzi, Maozu and Jinshachang deposits exhibit δ114/110Cd values ranging from +0.25‰ to +0.29‰ (n=3, +0.28‰ ± 0.02‰), +0.07‰ to +0.53‰ (n=8, +0.40‰ ± 0.17‰), ?0.10‰ to +0.44‰ (n=17, +0.11‰ ± 0.13‰), ?0.05‰ to +0.10‰ (n=6, +0.05‰ ± 0.06‰), +0.08‰ to +0.22‰ (n=11, +0.16‰ ± 0.05‰), respectively. The isotopic data of the studied deposits show the same characteristics as the MVT-type Pb-Zn deposit in figure 1/Cd–114Cd and Zn/Cd–114Cd.Cd isotope values of sphalerite share a similar evolution trend with their Zn isotope values display that Zn and Cd isotope composition of sphalerite have similar isotope fractionation mechanism. Furthermore, the Zn and Cd isotope values evolve toward isotopically heavier gradually from Maozu to Daliangzi, Jinshachang and Tianbaoshan, since the host rocks of these four deposits are all Dengying Formation of Upper Sinian, if assumed that the ore-bearing fluid of these four deposits came from the same hydrothermal fluid system, with the migration of fluid and the precipitation of minerals, the ore-bearing fluid would be enriched with more and more heavy isotopes of zinc and cadmium. Combining the geographical position and the geology of these four deposits, the pathways of ore-forming fluids were most likely started from Maozu, along Xiaojiang fault belt, Anninghe fault belt and their branch faults migrated to Daliangzi, Jinshachang and Tianbaoshan, respectively. Thus, Zn and Cd isotopes are good tools in tracing the pathway of ore-forming fluids in the studied Pb-Zn deposits, isotopically heavy Zn and Cd probably can be a geochemical halo in detecting remotely orebodies in a large hydrothermal orebody.Combined with regional, ore deposit geological characteristics and the S, Pb, Zn, Cd isotopes values and correlation, we infer that the metallogenic processes involved in the studied Pb–Zn deposits are as follows. Tectonic events related to the Indosinian Orogeny and post-Late Triassic completion of suturing between the Indochina and South China blocks around the study area led to the development of a series of thrust belts and foreland basins on the periphery of the SYG triangle. During diagenesis in these foreland basins, basinal brines formed from seawater or evaporative brines buried with sediments. Orogenesis during the Late Triassic contributed to long-distance migration and accumulation of basin brines, driven by gravity and topography. Evaporative brines and dissolved halite provided the chloride for metal complexation, while clastic basinal sediments and folded basement provided Zn, Pb, Fe, and other ore-forming metals. The basin brines then migrated along major faults and associated fracture zones or karst systems into reactive carbonates, finally accumulating in different open areas. During this migration, the basin brines evolved into metal-bearing fluids through the extraction of ore-forming metals from upper Sinian and Devonian to lower Permian sedimentary rocks or Proterozoic folded basement, while evaporative brines in host strata evolved into reduced S-bearing fluids through TSR. Faults provided a connection for the mixing of metal-bearing and reduced-S-bearing fluids, leading to precipitation of ore minerals and formation of deposits. In conclution, the mixture of metal-bearing fluids and reduced-S-bearing fluids is the main mechanism of ore precipitation and the formation of Pb-Zn deposit.