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Study On Geochemical Characteristics Of Copper(Gold), Iron Deposits In The Western Section Of Bangonghu-Nujiang Metallogenic Belt, Tibet

Posted on:2010-03-10Degree:MasterType:Thesis
Country:ChinaCandidate:Y TianFull Text:PDF
GTID:2120360272996253Subject:Mineralogy, petrology, ore deposits
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The research area is located in the western area of the Qingzang-Tibet Plain. The geological work degree is low, the gap are many, regardless of the known ore deposit is in quantity or the quality all also is insufficient to reflect the mineralization truly the true self. Tibet's copper mine holds the important status in China, east Tibet's Yulong porphyry copper mine belt is the Chinese cainozoic era most important hypogene deposit concentrates the habitat, but Ban Gonghu the - Nujiang collision structure belt also has the similar mineralization condition, although the known formation ore deposit are not many, but it has the good prospecting prospect. Along with the social development need, it is increase to metal minerals demands and the mining quantity and so on the copper, iron, in the national economy construction to under the mid-west shift overall strategy instruction, we have sought the century our country national economy construction the new raw material base on diligently an extremely urgent duty, but south the Qingzang-Tibet Plain is our country non-ferrous metal and the precious metal mineral resource high degree of concentration area. Therefore, under the western big development background, forecasting the mineral resource potential appraisal was one item imperative. Forecast to the known ore deposit dissect and the mineralization forecast to the Tibet ore deposit resources strength appraisal the positive function, this also was the foundation to forecast this area mineral resource strength.This article take the western section of Bangonghu - Nujiang mineralization belt in Tibe the Duobuza, Gaerqiong Fuye and Caima deposits as the object of study, through petrology, the petrochemistry, the trace element and analyses and so on rare-earth element geochemistry determines Ban Gonghu west the - Nujiang mineralization belt the section and the mineralization related magmatic rock type, the rock series; Analyzing its source area nature, becomeing the crag structural environment and so on. And it discusses mineralization related magmatic rock U-P the SHRIMP zircon age geological significance in this area.Through to above question research, it has yielded the main result as follow:1. It may see Tibet area the western section of Bangonghu - Nujiang mineralization belt in Tibe from the constant element and the trace element analysis of the mineralization related magmatic rock which belongs to the potassium unreliable petrographic province and enriched K and Ca in the alkali series row arc-shaped archipelago porphyry, in which Duobuza mining areas and Fuye mining area displays obvious rich K poor Na, Gaerqiong and Caima mining area relatively are enriched Na.Duobuza mining areas and the mineralization related granite-porphyry formed in the collision time, Gaerqiong mining area granite-porphyry formed after the collision jacks the time, Fuye mining area diorite-porphyrite formed in the tectonic plate collision earlier period, the Caima mining area granite-porphyry formed before the tectonic plate collision the transitional stage which jacks after the collision.2.It may see from the rare-earth element analysis: Duobuza, Caima and Gaerqiong and the mineralization related magmatic rock rare-earth element distribution curve has certain similarity, namely hasδEu or concentrates weakly for the weak loss, the weight rare earth fractionation degree low characteristic, suggests these magmatic rocks to be supposed for the shell curtain granite. Although these three mining areas and the mineralization related magmatic rock formed the time is possibly different, but the mantle rock magma all are possibly once had the big scale diapire function, the rock magma which was in the diapire process, mixed intensely with the earth's crust material dyes, and took place by the force way. Fuye mining area rare-earth element characteristic compares other three mining areas to have certain difference, the light rare earth content is low, light, the heavy rare earth fractionation is not obvious, its rare-earth element partition curve displays the model the intermediate rock characteristic, the rare earth partition curve demonstrates the Eu serious loss. Its reason possibly has following several points: (1) diorite-porphyrite source area possibly has the plagioclase feldspar remaining; (2) existence plagioclase feldspar fractional crystallization; (3) later period silk quater lithification, the mineralization and so on created in the diorite-porphyrite Eu drag-out.3. Through Fuye mining area and the Caima mining area including ore porphyry zircon U-Pb SHRIMP measured the year indicated, Fuye mining area ore rock body age for 130±1.4Ma, the Caima mining area ore rock body age divides into three groups respectively be 173.8±2.2 Ma, 153.8±1.9Ma, 123.4±13Ma, possibly forms on behalf of the Caima mining area magmatic rock in the Mt. yanshan early time (173.8±2.2 Ma), afterwards passes through 153.8±1.9Ma hydrothermal transformation, finally in Mt. yanshan intermediate stage (123.4±13Ma) again process hydrothermal transformation. The newest age has possibly represented the Caima mining area mineralization age. Compared the conclusion with the Caima mining area, the trace element analysis obtains the Caima mining area granite-porphyry formed before the tectonic plate collision the transitional stage conclusion which jacks after the collision tallies.4. Analyzing from fluid inclusion laser Laman can see two copper mine mining area quartz inclusion by CO2 primarily in the Duobuza and Gaerqiong, which represent a kind of relative oxidized environment, but the mining area quartz inclusion by CH4 primarilyin Fuye and Caima, which represents a kind of weak return to original state and the weak oxidation transitional environment. It is different in Fuye from Caima mining area garnet and the diopside demonstrated formed the environment is one kind restores the environment, but the Caima mining area garnet and the diopside demonstrated formed the environment is one kind of oxidized environment.5. Silica isotope analyses demonstrated the research area four mining area various types rockδ30Si the value distributes in the hydrothermal quartz scope, approaches in the secondary enlargement quartz.Four mining area various types rocks δ18O the value distributes in the fire becomes in the quartz scope.It ndicated silicon dioxide originates the hydrothermal which forms in the rock magma or the rock magma.6. Carbon oxygen isotope analysis demonstrated carbon which is in Caima mining area skarns possibly mainly comes from the mantle, but does not remove the atmospheric precipitation and the wall rock dissolved material ingredient permeated factors, the carbon in the marble origin may come from the carbonate dissolution, the carbon in the magnetite marble may originate from the marine facies carbonate rocks dissolution or the low temperature alteration function; Fuye mining area rock sample the carbon in Fuye mining area rock sample possibly originates from the marine facies carbonate rocks dissolution or the low temperature alteration function; the carbon in Gaerqiong mining area possibily main originates from marine facies carbonate rocks dissolution.
Keywords/Search Tags:Ban Gonghu - Nujiang mineralization belt, geochemistry, zircon SHRIMP measures year, Tibet
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