| The Chipu Pb-Zn deposit in Ganluo County,Sichuan Province is one of the famous large-scale Pb-Zn deposits in China's Sichuan-Yunnan region.Its tectonic setting is located on the western edge of the Yangtze plate,and on the east side of the northern section of the Kangzi axis,belonging to the west side of the Upper Yangtze block.Proterozoic Kangdian-basis complex belt marginal Paleozoic easteast carbonate platform,controlled by the Malaha break,belongs to Ganluo Xiaojiang metallogenic belt.Through collecting,sorting,and observing the data of predecessors,the orthopedic specimens were described by indoor observation,the identification and analysis under the microscope,the identification of light films and thin sections,and the use of electron probes and chemical analysis methods to summarize the tectonic settings and geological characteristics of the study area.Understand the material composition and structural characteristics of ores,identify the mineral composition and structure of ores,and the relationship between ore minerals and gangue minerals.Analyze the ore genesis in the region,and divide the ore-forming period,and the types of mineral deposits.It was discussed.The research area was produced on the east side of the Ganluo Xiaojiang fault zone-the upper plateau of the Malaha break.In the study area,except for the undiscovered and missing Carboniferous and Cretaceous systems in the Lower Sinian System,the remaining layers are visible,mainly Dengying Formation,Qiongzhusi Formation,and Canglangpu Formation.The Chipu Pb-Zn bed mainly occurs in the Upper Sinian Dengying Formation.The main lithologies are algae-rich dolomite,microcrystalline dolomite and bamboo-leafed dolomite.The ore body is layered,lenticular,and the occurrence of the surrounding rock is basically the same,and is controlled by strata control.It is the tidal flat-tidal?local water stagnation lagoon?environment.Wall rock alterations are weak.The ore minerals in the mining area are mainly galena,sphalerite and pyrite,followed by chalcopyrite and copper,lead and sulfur minerals.Gangue minerals are mainly dolomite,quartz and calcite.The secondary minerals are smithsonite,lead bran,etc.It is a typical medium-low temperature mineral group combination.Observed under the microscope,the ore structures are disseminated structures,spotted structures,veins,strips,brecciated structures.Through the ore's structural features,there are disseminated structures,spotted structures,vein structures,strips,brecciated structures,etc.,which are ore-bearing hydrothermal fluid along the pores,crevices,parallel bedding,or fractures of rocks.Bring the results of the generation.Ore structure has crumpling structure,erosion structure,milky structure,co-edge structure,rubber ring structure and so on.The ore structure shows the characteristics of hydrothermal filling and mineralization.Through the ore-fabric structure characteristics,three metallogenic periods were divided:the sedimentary-diagenetic stage during the sedimentary period,the hydrothermal period,and the epigenetic period.The order of mineral formation was determined.The hydrothermal action period is the main mineralization period and can be further divided into:pyrite stage,sphalerite-galena stage,galena-sphalerite,and carbonate stage.The Ga/In range of sphalerite is from 1.8 to 4.2,and the Zn/Cd value ranges from406 to 726.It is known that the ore-forming temperature is medium and low temperature.The Se content in pyrite is 0.3×10-6,0.3×10-6,and the S/Se values are172.8×104 and 166.4×104,respectively.Se and S in the eutectic pyrite that meet the sedimentary origin.The value of/Se.The component typomorphism of pyrite indicates that the deposit is pyrite for sedimentary origin.In summary,the metallogenic characteristics of the Chipu Pb-Zn deposit are characterized by low-medium temperature environment,sedimentary origin,and hydrothermal filling.It can be inferred that the Chipu Pb-Zn deposit is a deposit-modified deposit.Finally,comparing the Chipu Pb-Zn deposit with the Mississippi valley?MVT?Pb-Zn deposit,the Chipu Pb-Zn deposit conforms to the characteristics of the MVT-type Pb-Zn deposit but has its own uniqueness. |
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