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Western Hubei stratabound lead-zinc deposits of the ore sources

Author: TanManTang
Tutor: YaoShuZhen
School: China University of Geosciences
Course: Mineralogy,petrology, Mineral Deposit Geology
Keywords: Western Hubei STRATABOUND Lead and zinc Material source
CLC: P618.4
Type: Master's thesis
Year: 2009
Downloads: 309
Quote: 1
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Abstract

Western Hubei stratabound lead-zinc mine prospecting work in recent years made great progress, but related metallogenic theory lags behind. Qinling fold system across western Hubei and Yangtze paraplatform two a tectonic units, in order to break Qingfeng a wide-hsiang is bounded to the south part of the Yangtze platform, north part of the Qinling orogenic belt. Magmatic intrusive rocks in the region, mainly distributed in Huangling complex rock area, South Qinling orogenic belt Shennongjia dome localized. Stratigraphy of Quaternary from Archean outcrops to complete, which according to lithological, Sinian Doushantuo can be subdivided into four lithologic, DENGYING can be divided into three lithologic respectively, in steep mountain Da DENGYING have four layers with black shale development. Lead and zinc were found in western Hubei region is more than 150 points, mainly concentrated in the south of Qingfeng fracture, Shennongjia faulted dome periphery Huangling anticline northern margin of the other places. Lead-zinc ore formation is relatively stable, strictly controlled by the horizon, including Qingfeng fault near DENGYING dolomite, Yichang DENGYING brecciated dolomite, Shennongjia region Doushantuo brecciated dolomite, has obvious \This study examines the key cave mountain, river bathing, concave and Tan Son Gang Fort lead-zinc deposits (points) were collected or selected 30 rock geochemistry of ore samples, 20 samples of lead isotopes of sulfur, 4 CHO isotope samples, three samples of fluid inclusions were tested. Ice Caves Mountain, River lead-zinc mine located in Shennongjia bathed broken dome periphery, ore mainly occurs Doushantuoan four sets of black shales sandwiched among brecciated dolomite, ore-bearing rocks are sedimentary environment high system Domain restricted platform (dolomite) and lagoons (black shales). Ore minerals are sphalerite, galena, pyrite, dolomite (calcite), quartz, barite, etc., with the formation of multi-phase multi-stage characteristics. Rock geochemistry shows a metallic element has a high background values ??in chert rock belongs to the continental margin rather than biogenic submarine hydrothermal deposits were; chert, carbonaceous shale and dolomite were significant negative Ce anomalies, the former two are more obvious negative Eu anomalies, and dolomite weak positive Eu anomaly, negative anomalies are present, indicating a weaker during diagenesis hydrothermal fluids involved. Huangling Aozigang Zinc located off the north eastern edge of the dome, ore body at DENGYING toad hole section in the upper dolomite, ore-bearing rocks on behalf of a tidal flat facies carbonate platform deposition combinations. Ore minerals are mainly sphalerite, followed by smithsonite, pyrite; gangue minerals are dolomite (calcite), quartz. Rock geochemistry shows a metallic element has a high background values, REE distribution patterns showed a significant negative Ce anomaly in REE enrichment type, indicating that the process of adsorption in seawater precipitate containing a certain amount of Pb, Zn, etc. including the particles and cause sensitive elements Pb, Zn degree of enrichment. Tan lead-zinc mine located in Fort Artemisia Ping Qingfeng fault along the south side of West orebody is mainly produced in DENGYING top dolomite, ore-bearing rocks are sedimentary environment HST open platform system. Ore mineral assemblage mainly galena, sphalerite, pyrite, dolomite (calcite), quartz and fluorite. Wallrock dolomite has obvious negative Ce anomaly, Eu anomalies relative depletion of heavy REE REE distribution patterns, indicating that the role of the deposition process with a certain amount of hot water mixed with seawater. Pb isotope Zartman illustration, the ores and rocks are falling most upper crust, only a rock sample Tam Fort relatively close to the orogenic belt that bathed the river, concave sub Gang, lead and zinc ores and confining mountain cave Castle Rock and Tan lead-zinc ore is the main source of lead crust; while Tan Fort lead with lead-zinc rock orogenic crustal lead and lead a mixed source. Sulfur isotope sulfur-rich heavy is characterized, in which bathing river, concave sub-Gang, Ice Cave Hill lead-zinc δ ^{34 S between the value of 17.57-33.90 ‰, indicating that sulfur is mainly derived from marine sulfate salt formation itself that; while Tan lead-zinc ore galena Fort of δ ^{34 S was 12.35%, sulfate and evaporated in rocks intersect range, which should be due to orogenic hydrothermal sulfur The mix makes its δ ^{34 S to the range of metamorphic hydrothermal sulfur undergone some shift. Analysis of fluid inclusions indicate lead-zinc ore river bathing fluid inclusions gas composed mainly of methane, carbon dioxide less liquid composed mainly of water. Temperature measurement results showed that: Aozigang Zinc freezing temperature of -14.4 ℃ - 5.1 ℃, corresponding salinity W (NaCl)% of 9.79-18.27%; homogenization temperatures of 100.3 ℃ -171.6 ℃, statistical histogram shows a peak, indicating that the basic mineral formation experienced only a formative stage. Bathing River lead-zinc freezing temperatures -24.1 ℃ - 0.5 ℃, salinity corresponding to W (NaCl)% of 0.87-25.42%; homogenization temperatures of 80.6 ℃ -167.3 ℃. Histogram shows the peak value of about 3, indicating that the mineral formation has undergone three stages. Bathing river Aozigang Zinc ore-forming fluids are low temperature and pressure and mineralizing fluids mainly basin hot brine. Western Hubei Sinian Doushantuo and DENGYING several layers of black shale and dolomite content of metal elements analysis showed that: Whether in black shales or carbonate sedimentary diagenesis process, from the shell source Pb, Zn and other metal elements can to some extent the initial enrichment, and thus the formation of the ore source even mine (of) layer. Comprehensive analysis indicated that: 1. EXI stratabound Pb-Zn ore metals (Pb, Zn, etc.) mainly from the upper crust, the initial enrichment in Doushantuoan and lights in the black shales of carbonate rocks and stage in the diagenetic stage has been further enriched ore source beds and even the formation of ore (oriented) layer; orogeny in the latter can be affected by hydrothermal alteration and mineralization enrichment occurs again, local rock mixed in orogenic lead. 2 sulfur ore mainly from marine sulfate, ie the formation itself; Qingfeng lead-zinc mine near fault zones have a hydrothermal origin of sulfur added. 3 ore-forming fluids are mainly underground hot brine, such as brine or sedimentary basin of water, in the early stages of diagenesis in sedimentary basins with hot brine can be extracted ore leaching of metal and migrate to the inter-and dolomite breccia mineralization; in Late orogeny during the cycle of hot brine infiltration can carry mineral interlayer structural zone and fracture filling fissures formed in the early mineralization and ore (source) layer varying degrees of transformation. 4 EXI stratabound Pb-Zn mineralization model has transformed from a hydrothermal sedimentary mineralization trends to the process; different structural parts of different strata are endowed with subtle differences, can be divided sedimentary (with concave sub- Gang zinc represented), deposition - transformation type (represented by Ice Cave Hill Pb-Zn) and hydrothermal re-modeling (Artemisia Ping Tan fort west of lead and zinc as the representative) three kinds of genetic types.}}}

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