| Dengbuxian tungsten tin-polymetallic deposit in Hunan nonferrous group xiang dong tungsten co. LTD is located in the northward of Dengbuxian-Xi Tian depos its,which is oriented south and north.With good metallogenic conditions,located i n easily forming large ore-concentration area, this wolframite deposits is of high te mperature liquid filling quartz vein type.The north place is Nb-Ta mineral deposits of hydrothermal alteration rock mass..containing rich W, Sn, Nb, Ta and other valuable materials. It’s an old mine with a history of nearly a century. Since the exploration and mining from1950s to1960s of the last century, proven resources a re serious shortage and impact the stability and development of the mine.So it is of very important and economic significance to do this work. Thesis is done with a comprehensive system of basic collecting and organizing the data of past research, exploration, mining, etc.Through several times of field geological investigation an d a large number of indoor test analysis and comprehensive study, the systematic mineralogy, petrology, mineral deposit, ore deposit geochemistry, ore-forming model of summary for Dengbuxian tungsten tin-polymetallic ore deposit is done.Through the research, mainly points are the followings:1. The geological, geophysical and geochemical data of Xi Tian area shows t hat the region owns superior ore-forming geological conditions. Tungsten tin, lead a nd zinc polymetallic ore are related to the movement of the indosinian and yanshan period, closely related to acidic magmatic rocks. In the contact zone of rock mas s,there exists tungsten, tin, copper polymetallic mineralization, such as quartz vein type, metamorphic granite type tungsten tin polymetallic tungsten;Outside Contact z one is mainly form stratabound scheelite polymetallic skarn type, tectonic fracture z one type deposit, especially in the protuberant part of the contact zone and the coll apse area of the secondary fold axis, where are at favorable structures of mineraliz ation enrichment.2Dengbuxian tungsten deposit is a kind of high temperature hydrothermal qu artz vein type tungsten tin polymetallic deposit, according to the output characteristi c of the minerals vein and the relationship of mineral association in the mining are a. Dengbuxian tungsten ore is a kind of kiwolframite quartz vein type deposit. In t he light of the mineral composition, wall rock alterations, and fluid inclusion sugge st the characteristics of the ore-forming hydrothermal, combined with the activity ti me of metallogenic granitic magma and the features of ore-controlling tectonic, mi neralization period of time is divided into4stages in Dengbuxian vein tungsten. In space, the mineral quartz vein mineralization have the characteristics that there are clearer vertical zoning and horizontal zoning; The upper vein is cassiterite-black tungsten ore belt;The middle part is wolframite-copper pyrites (molybdenite) belt;The lower or deeper is scheelite-arsenopyrite belt; The ore-forming elements co mbination from top to bottom is W、Sn'Wn Cu (Mo)'W、Ws (Cu). Thus, acco rding to mineral assemblage and mineralization in vein vertical zoning features, It i s realized that Dengbuxian tungsten deposit has the typical characteristics of reverse zoning.3. It is tested that the fine grained mica granite zircon LA-ICP-MS U-Pb age of Dengbuxian rock mass is (159±0.8Ma),which is keeping with the predece ssors of molybdenite Re-Os isotope age. The causes of tin deposit is closely linked to Dengbuxian rock mass and tin field complex massif. The producton belongs to the same tectonic-magmatic-ore-forming fluid system, combined with the recent year s research result of Xi Tian region tungsten tin diagenetic metallogenic epoch.Com pare this deposit with the Nan Ling region tungsten tin polymetallic metallogenic a ge, it shows that south China tungsten tin polymetallic metallogenic epoch mostly c oncentrates on150～160Ma, belonging to late Mesozoic Jurassic. Therefore, late Mesozoic Jurassic is the outbreak period of the Nan Ling region mineralization. Th e area is in the same diagenetic mineralization system, and unified the geodynamics background. In the dynamics of regional crustal extension, thinning environment, f ormed a series of large-super large tin polymetallic tungsten.4. Dengbuxian two-mica granite is strongly peraluminous, with high Si and al kali contents and low Mg and Fe contents, showing geochemical characteristics of high differentiation. Granite is rich in large ion lithophile elements (Cs, Rb and K) and high field strength elements (Th U and Pb), but deplete in Ba, Sr, Ti and P. These two-mica granitic rocks have low FREE content, pronounced negative Eu an omaly and LREE enrichment. The chondrite-normalized REE distribution pattern is right-inclining gull distribution trend. On the basis of above rock element geochem ical characteristics, Dengfuxian two-mica granite is believed to be S-type granite.5. Through this paper testing and combining previous data, researching part of sulfide of Dengbuxian quartz vein type wolframite deposits. Results show that the δ34S value between2%o～+0.61‰, of which-1.5‰～0.5%o tended to between, average of-0.94‰. In Dengbuxian tungsten tin polymetallic deposit metallogeni c hydrothermal2δ34S∑is approximately equal to chalcopyrite834S roughly34-0.94‰. Which stated that chalcopyrite sulfur value represents the total sulfur of the ore-forming solution. And sulfur isotopic composition concentrated near the0‰has o bvious effect of tower, which shows that sulfur source of sulfide generated by the ore-forming hydrothermal in a single is igneous origin. Which reflects sulfur source related to mineralization of important material comes from homogenization magmat ic hydrotherm of the high temperature of sulfur isotope, without formation of foreig n sulfur to join, indicated sulfur of the ore-forming process may mainly comes fro m the deep magma formed the area of ancient crustal remelting. The two-mica gra nite rock mass in the mining area and similar diagenetic metallogenic epoch shows that the ore-forming fluid is mainly related to two-mica granite rock mass in the mining area6. By comprehensive research of Dengbuxian vein tungsten deposit such as g eological characteristics, the characteristics of main minerals output and composition in vein, ore deposit geochemistry, diagenetic mineralization age, ore-forming fluid and ore-forming mechanism, etc, it is Establishsd the type of deposit metallogenic model in the region. Comparing geological characteristics and metallogenic mechanis m of with the Nanling region important tungsten deposit,"five floors and basement " prospecting model is established according to the thickness of vertical zoning reg ularity in the vein.Considering the feature of regional mineralization, the type depo sit prospecting model of the tin area is established... |
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