Lead-zinc deposits in Northeast Yunnan MAOPING I mine group , alteration - mineralization zoning mode of
|School||Kunming University of Science and Technology|
|Course||Mineral prospecting and exploration|
|Keywords||Alteration zoning Mineralization zoning Ore-forming fluids Three-dimensional alteration - facies mapping MAOPING lead-zinc deposits Northeast Yunnan|
The Zhaotong MAOPING Zn mining area is northeast of Yunnan rich lead-zinc polymetallic ore belt and a very large ore-forming potential ore concentration area, in the past, especially Genesis fresh to carry out their weak deposit of. In this thesis, occur in the inversion of the Cat Mountain anticline, West Wing, Upper Devonian slaughter group (D3zg2) crystalline dolomite I # mine group in the fault zone northeast of Yunnan lead-zinc-rich region gross gross floor lead-zinc Ping lead and zinc as the research object, the system to carry out mine three-dimensional alteration mapping and petrographic study, based on detailed study of geological and geological characteristics, focusing on the lead-zinc deposits I MAOPING mine group (group ) mineralization - Causes of alteration zonation, alteration and mineralization zonation model, combined with the analysis of fluid inclusions and isotopic tracer of the deposit. Thesis to take a look at the results and understanding of: (1) in accordance with the mine (of) body, the veins interspersed relations, mineral assemblages and ore texture and structure characteristics, diagenetic mineralization processes in the region include diagenesis of oil and gas of hydrothermal mineralization and supergene oxidation period. The hydrothermal mineralization period can be divided into five stages, including II, III stage is one of the major lead-zinc mineralization stages. A large number of solid bitumen found in the ore body and altered wall rock both directions diagenetic organic matter and hydrothermal ago signs of cracking, but also reflects the hydrothermal mineralization process of organic matter mixed with hydrogen and oxygen isotopes results support this inference. (2) to the periphery from the center of the ore body, bottom-up, alteration showing silicide → carbonate significant zonation of the silicide argillation → carbonation, dense block of high-grade ore mineralization → dense block pyrite shell → disseminated, vein, patchy low-grade ore → star point pyrite housing zoning characteristics of the mineral assemblages flag chalcopyrite, marcasite, pyrite, arsenopyrite, pyrite illite, galena, pyrite British siderite and dolomite, calcite. (3) horizontal belt pinch-out of the eastern end of the North-rich galena with instructions orebody. The vertical elements of the sub-band, Pb is located in the lower part, Zn front, indicating the presence of fluid additive effect. The banded ore fluid superimposed another evidence. II, III stage of mineralization elements occur in the vicinity of 670 to 784m superposition stage II mineralization over 784m. (4) The the pyrite shell is the product of the early fluid. Rich ores are the dense massive pyrite shell wrapped star point-like low-grade ore are pyrite shell wrapped in dense massive pyrite shell appears in the side of, and in the upper part of the lenticular ore bodies, within the bonanza and pyrite mine pentagonal dodecahedron crystal form is more in the bonanza site. Sulfide minerals from the ore body center to the sides and upper gradually become less ore constructed type from the bottom-up easier. (5) dolomite, quartz, pyrite ring band structure appears only in the edge and in the upper part of the bonanza, does not appear in the lower part, is a sign of fluid forward, guiding significance for prospecting. (6) the fluid has more than one activity center, along the fault the fractured zone channel from south to north east to the upward migration of fracture and formation is a key factor in the mineralization control. The evolution of the ore-forming fluid, there is a significantly lower temperature and pressure, salinity and density trend (not significant). The same stage of the fluid in the vertical direction, from the bottom upwards salinity, density is reduced, but the pressure and temperature increase. Stage II - high temperature and high pressure low-salt, low-density fluid; stage III temperature and low pressure low-salt, low-density fluid. The special combination of pyrite, dolomite crystal form analysis, the indicating crystals exothermic effect on the fluid properties can not be ignored. The quartz crystal crooked one-way fluid supply and flow occurred in the local loop. (7) mineralization age Yanshanian. Into minerals from the upper crust base construction, there are also the contribution of the Upper Devonian carbonate rock salt formation. Ore-forming fluids atmospheric water, hot brine, the organic water and metamorphic water mixed fluid, indicating the participation of organic matter and fluid leaching cycle of mineralization have a certain role, and metallogenic significance of the Emeishan basalt eruptions. (8) the establishment of the alteration and mineralization zoning mode helps the ore-forming fluid migration and accumulation and in-depth study of the enrichment and mineralization, indicated deep looking for blind ore bodies. According to expose the situation of the gross floor mine I mine group, there is still a lot of deep prospecting potential.