西藏努日铜钨钼矿床地质特征及成矿物质来源探讨
发布时间：2018-07-28 19:18
【摘要】：努日铜钨钼矿床位于冈底斯燕山—喜马拉雅期陆缘岩浆弧的东段、雅鲁藏布江板块缝合带北缘。矿体受矿区复式背斜控制,赋存在背斜与向斜共翼地段的比马组四段(K1b4)的层间破碎和节理裂隙带内。共圈定12个矿体,主要是为似层状、透镜状和脉状。矿石矿物主要是黄铜矿、辉钼矿、白钨矿,中-细粒自形半自形结构为主,浸染状、斑点状、块状构造。脉石矿物包括石榴子石、绿帘石、石英及极少量的方解石。辉钼矿微量元素表现为高场强元素(HFSE)亏损,LREE富集。辉钼矿中Y/Ho、Zr/Hf、Nb/Ta的比值变化范围较大,表明主成矿期成矿流体混入了外来流体,总体以早期成矿流体的物理化学性质为主。右倾稀土配分模式,负Eu异常和负Ce异常。负Eu异常可能是岩浆在分离结晶中大量斜长石晶出,使原始流体强烈亏损Eu;负Ce异常可能是因为初始流体为氧化环境,致使Ce3+氧化为Ce4+从而与稀土体系分离。白钨矿微量元素表现为亏损高场强元素(HFSE),富集LREE。Hf/Sm、Th/La、Nb/La比值范围都远低于1,而Y/Ho、Zr/Hf、Nb/Ta比值变化范围较大,暗示努日矿床的成矿流体总体以富Cl热液为主。在主成矿期不同程度混入了外来流体,总体特征仍以早期成矿流体的物理化学性质为主。ΣREE不高,右倾配分模式,稀土元素结构单一,特征值变化小,指示白钨矿中REE具有高度同源性。而弱δEu负异常,基本未见Ce异常或极弱的正Ce异常,很大程度上代表了成矿流体的还原环境特征。石榴子石及石英中流体包裹体?18OH2O值为-2.96~7.14‰。成矿热液主体为岩浆,迁移中接收了天水,热液由原生岩浆水逐渐过渡到原生岩浆水和天水的混合。硫化物的δ34S值波动很小,多为正值,偶见负值,典型塔式分布,向正值偏移。表明硫同位素均一化程度高,硫同位素没有强烈分馏,暗示硫的来源相对单一。铅同位素特征值均小于9.58,介于上地壳和地幔之间,指示出努日矿床成矿物质主要来源于幔源,在运移过程中可能混入了部分壳源物质。结合Re同位素综合分析发现,努日铜钼钨矿床的成矿物质中Mo可能来源于单一的深部幔源。而白钨矿则可能为来源于深部壳源岩浆结晶分异后富钨流体沿着构造裂隙运移过程中与围岩比马组地层发生接触交代反应,最终导致Ca2+与WO3-4结合形成了白钨矿。而成矿热液则主要为初始原生岩浆水逐渐过渡到原生岩浆水和天水的混合流体。S同位素结构较为单一,表明S的主要来源还是岩浆。Pb同位素显示矿床Pb为不含放射成因的普通铅,为混合源。
[Abstract]:The Nuri copper tungsten molybdenum deposit is located in the eastern section of the magma arc of the Yanshan Himalaya continental margin of Gangdise and the northern margin of the Yarlung Zangbo Suture Zone. The ore body is controlled by the compound anticline in the mining area, and there are four segments of the Bi Ma formation (K1b4) of the anticline and Syncline in the interlayer breakup and the joint fracture zone. The 12 ore bodies are delineated, mainly as stratiform and permeable. The ore minerals are mainly chalcopyrite, molybdenite, scheelite, medium to fine self shaped semi self shaped structure, disseminated, speckled and massive structures. The gangue minerals include pomegranite, epidote, quartz and a very small amount of calcite. The trace elements of the molybdenite are HFSE loss, LREE enrichment, Y/Ho and Zr/ in molybdenite. The ratio of Hf and Nb/Ta varies greatly, indicating that the ore-forming fluid in the main metallogenic period is mixed with foreign fluid, and the overall physical and chemical properties of the early metallogenic fluid are mainly. The right rare earth distribution pattern, negative Eu anomaly and negative Ce anomaly. The negative Eu anomaly may be a large number of diagonal feldspar crystals in the crystallization of the magma, causing a strong loss of Eu in the original fluid and negative Ce difference. It is often due to the oxidation environment of the initial fluid, resulting in the oxidation of Ce3+ to Ce4+ to separate the rare earth system. The trace elements of the scheelite are characterized by a loss of high field strength element (HFSE), the concentration of LREE.Hf/Sm, Th/La, Nb/La ratio is far below 1, while the Y/Ho, Zr/Hf, and Nb/Ta ratios vary greatly, suggesting that the ore-forming fluid in the Nu day deposit is generally rich in C. In the main metallogenic period, l has been mixed with foreign fluids in different degrees. The overall characteristics are still dominated by the physical and chemical properties of the early metallogenic fluid. The sigma REE is not high, the right distribution pattern, the rare earth element structure is single, the change of the eigenvalues is small, indicating that the REE is highly homologous in the scheelite, and the weak Delta Eu is negative, and there is no Ce anomaly or extremely weak. The normal Ce anomaly, to a great extent, represents the reduction environment of the ore-forming fluid. The fluid inclusion in the garnet and quartz is -2.96~7.14 per 1000. The main body of the hydrothermal fluid is -2.96~7.14 per thousand. The main body of the hydrothermal fluid is magma, and the transfer of the hydrothermal fluid from the primary rock to the mixture of primary rock and Tianshui. For positive, negative, negative, negative, typical tower distribution, migration to positive value. It shows that the isotopes of sulfur isotopes are high and sulfur isotopes have no strong fractionation, suggesting that the source of sulfur is relatively simple. The characteristics of lead isotopes are less than 9.58, between the upper crust and the mantle, indicating that the ore-forming minerals are mainly derived from the mantle source and can be transported during the migration process. In combination with Re isotopic analysis, it is found that Mo may be derived from a single deep mantle source in the metallogenic material of the Nuri copper molybdenum tungsten deposit, while the scheelite may be derived from the contact of the rich tungsten rich fluid in the process of tectonic fissures in the process of tectonic fractures. The reaction eventually leads to the combination of Ca2+ and WO3-4 to form scheelite, and the metallogenic hydrothermal solution is mainly a single primary primary rock slurry that gradually transitioning to primary rock water and Tianshui. The.S isotope structure of the mixed fluid is relatively simple, indicating that the main source of S is that the.Pb isotope of the magma deposit shows that Pb is a common lead without radioactive origin and is a mixed source.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.6;P618.41
本文编号：2151322
[Abstract]:The Nuri copper tungsten molybdenum deposit is located in the eastern section of the magma arc of the Yanshan Himalaya continental margin of Gangdise and the northern margin of the Yarlung Zangbo Suture Zone. The ore body is controlled by the compound anticline in the mining area, and there are four segments of the Bi Ma formation (K1b4) of the anticline and Syncline in the interlayer breakup and the joint fracture zone. The 12 ore bodies are delineated, mainly as stratiform and permeable. The ore minerals are mainly chalcopyrite, molybdenite, scheelite, medium to fine self shaped semi self shaped structure, disseminated, speckled and massive structures. The gangue minerals include pomegranite, epidote, quartz and a very small amount of calcite. The trace elements of the molybdenite are HFSE loss, LREE enrichment, Y/Ho and Zr/ in molybdenite. The ratio of Hf and Nb/Ta varies greatly, indicating that the ore-forming fluid in the main metallogenic period is mixed with foreign fluid, and the overall physical and chemical properties of the early metallogenic fluid are mainly. The right rare earth distribution pattern, negative Eu anomaly and negative Ce anomaly. The negative Eu anomaly may be a large number of diagonal feldspar crystals in the crystallization of the magma, causing a strong loss of Eu in the original fluid and negative Ce difference. It is often due to the oxidation environment of the initial fluid, resulting in the oxidation of Ce3+ to Ce4+ to separate the rare earth system. The trace elements of the scheelite are characterized by a loss of high field strength element (HFSE), the concentration of LREE.Hf/Sm, Th/La, Nb/La ratio is far below 1, while the Y/Ho, Zr/Hf, and Nb/Ta ratios vary greatly, suggesting that the ore-forming fluid in the Nu day deposit is generally rich in C. In the main metallogenic period, l has been mixed with foreign fluids in different degrees. The overall characteristics are still dominated by the physical and chemical properties of the early metallogenic fluid. The sigma REE is not high, the right distribution pattern, the rare earth element structure is single, the change of the eigenvalues is small, indicating that the REE is highly homologous in the scheelite, and the weak Delta Eu is negative, and there is no Ce anomaly or extremely weak. The normal Ce anomaly, to a great extent, represents the reduction environment of the ore-forming fluid. The fluid inclusion in the garnet and quartz is -2.96~7.14 per 1000. The main body of the hydrothermal fluid is -2.96~7.14 per thousand. The main body of the hydrothermal fluid is magma, and the transfer of the hydrothermal fluid from the primary rock to the mixture of primary rock and Tianshui. For positive, negative, negative, negative, typical tower distribution, migration to positive value. It shows that the isotopes of sulfur isotopes are high and sulfur isotopes have no strong fractionation, suggesting that the source of sulfur is relatively simple. The characteristics of lead isotopes are less than 9.58, between the upper crust and the mantle, indicating that the ore-forming minerals are mainly derived from the mantle source and can be transported during the migration process. In combination with Re isotopic analysis, it is found that Mo may be derived from a single deep mantle source in the metallogenic material of the Nuri copper molybdenum tungsten deposit, while the scheelite may be derived from the contact of the rich tungsten rich fluid in the process of tectonic fissures in the process of tectonic fractures. The reaction eventually leads to the combination of Ca2+ and WO3-4 to form scheelite, and the metallogenic hydrothermal solution is mainly a single primary primary rock slurry that gradually transitioning to primary rock water and Tianshui. The.S isotope structure of the mixed fluid is relatively simple, indicating that the main source of S is that the.Pb isotope of the magma deposit shows that Pb is a common lead without radioactive origin and is a mixed source.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.6;P618.41
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