In situ U-Pb dating and trace elements of magmatic rutile from Mujicun Cu-Mo deposit,North China Craton:Insights into porphyry mineralization

Porphyry Cu(Mo-Au)deposit is one of the most important types of copper deposit and usually formed under magmatic arc-related settings,whilst the Mujicun porphyry Cu-Mo deposit in North China Craton uncommonly generated within intra-continental settings.Although previous studies have focused on the age,origin and ore genesis of the Mujicun deposit,the ore-forming age,magma source and tectonic evolution remain controversial.Here,this study targeted rutile(TiO_(2))in the ore-hosting diorite porphyry from the Mujicun Cu-Mo deposit to conduct in situ U-Pb dating and trace element composition studies,with major views to determine the timing and magma evolution and to provide new insights into porphyry Cu-Mo metallogeny.Rutile trace element data show flat-like REE patterns characterized by relatively enrichment LREEs and depleted HREEs,which could be identified as magmatic rutile.Rutile U-Pb dating yields lower intercept ages of 139.3–138.4 Ma,interpreted as post magmatic cooling timing below about 500℃,which are consistent or slightly postdate with the published zircon U-Pb ages of diorite porphyry(144.1–141.7 Ma)and skarn(146.2 Ma;139.9 Ma)as well as the molybdenite Re-Os ages of molybdenum ores(144.8–140.0 Ma).Given that the overlap between the closure temperature of rutile U-Pb system and ore-forming temperature of the Mujicun deposit,this study suggests that the ore-forming ages of the Mujicun deposit can be constrained at 139.3–138.4 Ma,with temporal links to the late large-scale granitic magmatism at 138–126 Ma in the Taihang Orogen.Based on the Mg and Al contents in rutile,the magma of ore-hosting diorite porphyry was suggested to be derived from crust-mantle mixing components.In conjunction with previous studies in Taihang Orogen,this study proposes that the far-field effect and the rollback of the subducting Paleo-Pacific slab triggered lithospheric extension,asthenosphere upwelling,crust-mantle interaction and thermo-mechanical erosion,which jointly facilitated the formation of dioritic magmas during the Early Cretaceous.Subsequently,the dioritic magmas carrying crust-mantle mixing metallic materials were emplaced and precipitated at shallow positions along NNE-trending ore-controlling faults,eventually resulting in the formation of the Mujicun Cu-Mo deposit within an intracontinental extensional setting.

Petrogenesis and Physicochemical Conditions of Fertile Porphyry in Non-arc Porphyry Mineralization:A Case from Habo Porphyry Cu-Mo Deposits,SW China

The Habo deposit is a typical porphyry Cu-Mo deposit in the Ailaoshan–Red River metallogenic belt.Ore minerals in the Habo deposit typically occur as veins in the monzonite porphyry.Zircon U-Pb dating suggests that the monzonite porphyry formed at 35.07±0.38 Ma.The monzonite porphyry is characterized by high SiO_(2),Al_(2)O_(3),K_(2)O and Na_(2)O contents,with A/CNK ratios ranging from 0.97 to 1.02.All samples exhibit fractionated REE patterns,characterized by high(La/Yb)N ratios(9.4–13.6,average of 11.2).They show adakite-like geochemical features,high Sr concentrations(627–751 ppm,average of 700 ppm),low Y concentrations(15.13–16.86 ppm,average of 15.81 ppm)and high Sr/Y values(39.5–47.4,average of 44.3).These samples have high initial^(87)Sr/^(86)Sr ratios(0.7074–0.7076)and negativeεNd(t)values(-5.1 to-3.7),whereas the zirconεHf(t)values range from-2.2 to+0.4,suggesting that the monzonite porphyry was derived from the partial melting of a thickened juvenile lower crust.The oxygen fugacity,calculated on the basis of the chemical composition of the amphiboles,shows?NNO values ranging from+1.65 to+2.16(average of 1.94)and lg(fO_(2))ranging from-12.72 to-11.99(average of-12.25),indicating that the monzonite porphyry has high oxygen fugacity.Zircons have high Ce^(4+)/Ce^(3+)ratios(29.29–164.24,average of 84.92),with high?FMQ values ranging from+0.50 to+1.51(average of 0.87)and high lg(fO_(2))values ranging from-14.72 to-12.85(average of-14.07),which also indicates that the oxygen fugacity of the magma was high.The dissolved water content of the Habo monzonite porphyry is 9.5–11.5 wt%,according to the geochemical characteristics,zircon-saturation thermometry(692–794°C)and the mineral phases(amphibole,no plagioclase)in the deep magma chamber.Combined with previous studies,we propose that the high oxygen fugacity and high water content of magma played key roles in controlling the formation of the Habo and other Cu-Mo-Au deposits in the Ailaoshan–Red River metallogenic belt.

Geochemical Characteristics and Significance of Major Elements, Trace Elements and REE in Mineralized Altered Rocks of Large-Scale Tsagaan Suvarga Cu-Mo Porphyry Deposit in Mongolia

The alteration types of the large-scale Tsagaan Suvarga Cu-Mo porphyry deposit mostly comprise stockwork silicification, argillization, quartz-sericite alteration, K-silicate alteration, and propylitization. The mineralized and altered zones from hydrothermal metallogenic center to the outside successively are Cu-bearing stockwork silicification zone, Cu-beating argillized zone, Cu-Mo-bearing quartz-sericite alteration zone, Cu-Mo-bearing K-silicate alteration zone, and pro- pylitization zone. The K-silicate alteration occurred in the early phase, quartz-sericite alteration in the medium phase, and argillization and carbonatization （calcite） in the later phase. Ore-bearing-altered rocks are significantly controlled by the structure and fissure zones of different scales, and NE- and NW-trending fissure zones could probably be the migration pathways of the porphyry hydrothermal system. Results in this study indicated that the less the concentrations of REE, LREE, and HREE and the more the extensive fractionation between LREE and HREE, the closer it is to the center circulatory hydrothermal ore-forming and the more extensive silicification. The exponential relationship between the fractionation of LREE and HREE and the intensity of silicification and K-silicate alteration was found in the Cu-Mo deposit studied. The negative Eu anomaly, normal Eu, positive Eu anomaly and obviously positive Eu anomaly are coincident with the enhancement of Na2O and K2O concentrations gradually, which indicated that Eu anomaly would be significantly controlled by the alkaline metasomatism of the circulatory hydrothermal ore-forming system. Therefore, such characteristics as the positive Eu anomaly, the obvious fractionation between LREE and HREE and their related special alteration lithofacies are suggested to be metallogenic prognostic and exploration indications for Tsagaan Suvarga-style porphyry Cu-Mo deposits in Mongolia and China.

Geochronological Constraints on the Haftcheshmeh Porphyry Cu-Mo-Au Ore Deposit, Central Qaradagh Batholith, Arasbaran Metallogenic Belt, Northwest Iran

The Haftcheshmeh porphyry Cu-Mo-Au deposit in the Arasbaran metallogenic belt （AMB） of NW Iran contains more than 185 Mt of ore, with a grade ranging from 0.3% to 0.4%. It is hosted within a porphyritic diorite to granodiorite intruded into an older gabbro - diorite intrusion. 40Ar/39Ar analyses of primary magmatic hornblende from the granodiorite porphyry and gabbro - diorite show plateau ages of 26.41 ± 0.59 Ma, with an inverse isochron age of 25.9 ± 1.0 Ma and a plateau age of 27.47 ± 0.17 Ma, with an inverse isochron age of 27.48 ± 0.35 Ma for these two rock types, respectively. Comparing these new age data with those from the nearby Sungun （20.69 ± 0.35 Ma） and Kighal porphyry deposits defines a northwest-southeast Cu-Mo-Au mineralization zone extending for 20 km over the time span of-27 to 20 Ma. Geochemically, Haftcheshmeh rocks are calc-alkaline with high potassium affinities with tectonic setting in relation to volcanic arc setting. Large ion lithophile elements （LILE） such as Th, U and K show enrichment on a primitive mantle normalized diagram （specially Pb）, and are depleted in high field strength elements （HFSE） such as Ti and Nb, pointing to a mantle magma source contamination with crustal materials by subducted oceanic crust.

Re-Os isotopic dating and geological significance of molybdenite from Xintian Cu-Mo polymetallic deposit in Yanbian,Jilin

Xintian polymetallie deposit is a hydrothermal vein type Cu-Mo deposit. Analysis on Re-Os isotopic dating for the molybdenite from this deposit is undertaken to determine metallogenic epoch and dynamics setting of the deposit. Re-Os isotopic dating for the molybdenite yields model ages ranging from 123.9 ± 1.9 Ma to 124.7 ± 1.8 Ma, with a weighted mean age of 123.4 ±0.81 Ma, and an isochron age of 127 ± 16 Ma, MSWD = 0.25, indicating that the metallization was at late Yanshanian. The content of Re in molybdenite is （330.1 ±4.0-367.9 ± 3.1 ） xl0^-6, which demonstrates mantle derived metallogenic sources. Integrating the region-al tectonic evolution and the metallogenic characteristics of other contemporaneous Cu-Mo deposits in the re-gion, it is suggested that the Cu-Mo mineralization of this deposit occurred in an active epieontinental environ-ment under lithospheric extension resulted from the subduction of the Izanagi plate to the Paleo-Asia continental margin at late Yanshanian. The Mantle wedge was partially melted with large amount of metallogenic elements dissolved in it. Under the favorable conditions of crust-mantle interaction, large-scale magmatic activity turns out to be the important mechanism of the mineralization of many Cu-Mo deposits in the Xiaoxingan Range-Zhangguangcai Mountain metallogenic belt, including the Xintian Cu-Mo polymetallic deposit.

Re-Os geochronology of Cu and W-Mo deposits in the Balkhash metallogenic belt,Kazakhstan and its geological significance

The Central Asian metallogenic domain （CAMD） is a multi-core metallogenic system controlled by boundary strike-slip fault systems. The Balkhash metallogenic belt in Kazakhstan, in which occur many large and super-large porphyritic Cu--Mo deposits and some quartz vein- and greisen-type W-Mo deposits, is a well-known porphyritic Cu--Mo metallogenic belt in the CAMD. In this paper 11 molybdenite samples from the western segment of the Balkhash metallogenic belt are selected for Re--Os compositional analyses and Re--Os isotopic dating. Molybdenites from the Borly porphyry Cu deposit and the three quartz vein-greisen W--Mo deposits--East Kounrad, Akshatau and Zhanet--all have relatively high Re contents （2712--2772 μg/g for Borly and 2.267--31.50 μg/g for the other three W-Mo deposits）, and lower common Os contents （0.670-2.696 ng/g for Borly and 0.0051--0.056 ng/g for the other three）. The molybdenites from the Borly porphyry Cu--Mo deposit and the East Kounrad, Zhanet, and Akshatau quartz vein- and greisen-type W-Mo deposits give average model Re--Os ages of 315.9 Ma, 298.0 Ma, 295.0 Ma, and 289.3 Ma respectively. Meanwhile, molybde- nites from the East Kounrad, Zhanet, and Akshatan W-Mo deposits give a Re--Os isochron age of 297.9 Ma, with an MSWD value of 0.97. Re--Os dating of the molybdenites indicates that Cu-W-Mo metallogenesis in the western Balkhash metallogeuic belt occurred during Late Carboniferous to Early Permian （315.9--289.3 Ma）, while the porphyry Cu--Mo deposits formed at ~316 Ma, and the quartz vein-greisen W--Mo deposits formed at ~298 Ma. The Re--Os model and isochron ages thus suggest that Late Carboniferous porphyry granitoid and pegmatite magmatism took place during the late Hercy- nian movement. Compared to the Junggar-East Tianshan porphyry Cu metallogenic belt in northwestern China, the formation of the Cu-Mo metallogenesis in the Balkhash rnetallogenic belt occurred between that of the Tuwu-Yandong in East Tianshan and the Baogutu porphyry Cu deposits in West Junggar. Collectively, the large-scale Late Carboniferous porphyry Cu-Mo metallogenesis in the Central Asian metallogenic domain is related to Hercynian tectono-magmatic activities.

Geology,Geochemistry and Zircon U-Pb Geochronology of Porphyries in the Dabate Mo-Cu Deposit,Western Tianshan,China:Petrogenesis and Tectonic Implications

The Dabate Mo-Cu deposit is a medium-sized porphyry-type deposit in the Sailimu Lake region, western Tianshan, China. We present the geology, geochemistry and zircon U-Pb geochronology of granite porphyries from the Dabate district with the intent to constrain their tectonic setting and petrogenesis. Porphyries in the Dabate district include granite porphyry I（gray white color with large phenocrysts）, granite porphyry II（pink color with small phenocrysts） and quartz porphyry. Granite porphyry II is the Cu and Mo ore-bearing granitoid in the Dabate deposit. LA-ICPMS zircon U-Pb analyses indicate that granite porphyry II was emplaced at 284.2±1.8 Ma. Granite porphyry I and II have similar geochemical features and are both highly fractionated granites：（1） They have high SiO2 content（70.93–80.18 wt% and 72.14–72.64 wt%, respectively）, total alkali（7.58–8.95 wt% and 9.35–9.68 wt%, respectively）, mafic index（0.95–0.98 and 0.93–0.94, respectively） and felsic index（0.79–0.94 and 0.89–0.91, respectively）;（2） They are characterized by pronounced negative Eu anomaly, ＂seagullstyle＂ chondrite-normalized REE patterns and ＂tetrad effect＂ of REE;（3） They are rich in Rb, K, Th, Ta, Zr, Hf, Y and REE, but depleted in Sr, P, Ti and Nb. The magma of granite porphyries in Dabate can be interpreted to have been generated by partial melting of the upper crust due to mantle-derived magma underplating in a post-collisional extensional setting.

Rare Earth Element Behaviour in theWunugetushan Copper - Molybdenum Deposit,Inner Mongolia, and Its Implications

Considering porphyry and wall rocks as a whole system, the behaviour of rare earth elements (REE) in hydrothermal alteration and mineralization of the exceedingly large Wunugetushan porphyry Cu-Mo deposit of Inner Mongolia has been studied. It has been found for the first time that there exists complementary REE variation in hydrothermal alteration between porphyry and wall rocks, and Eu depletion has certain significance in indicating mineralization. Based on an analysis of the variation in REE contents of relevant minerals during the hydrothermal alteration, the ore-forming fluids are inferred to be depleted in ∑REE, comparatively enriched in ∑Y and strongly depleted in Eu. In the intermediate-strong alteration zones, porphyry and wall rock took part in hydrothermal metasomatism and alteration almost in equal ratio mass. Furthermore, studies of REE and hydrogen and oxygen isotopes and fluid inclusions confirm the existence of hydrothermal convection and the possibility of supplying part of ore materials by the wall rock and indicate that the application of REE geochemistry in mineral prospecting is promising.

Late Jurassic Cu-Mo Mineralization at the Zhashui-Shanyang District,South Qinling,China:Constraints from Re-Os Molybdenite and Laser Ablation-Inductively Coupled Plasma Mass Spectrometry U-Pb Zircon Dating

The Zhashui-Shanyang district is one of the most important sulfide deposits in the Qinling Orogen where the formation of porphyry-skarn Cu-Mo deposits has a close genetic link with the Yanshannian magmatism.Laser Ablation-Inductively Coupled Plasma Mass Spectrometry（LA-ICP-MS） U-Pb zircon dating of two granodiorite intrusions（Xiaohekou and Lengshuigou deposits）was investigated in the Zhashui-Shanyang district and the rock-forming ages obtained from 148.3±2.8 to 152.6±1.2 Ma,averaging 150.5 Ma,accompanied by a younger disturbance age of 144.3±1.7 Ma in the Lengshuigou intrusion,which is in excellent agreement with published sensitive high resolution ion micro-probe（SHRIMP）zircon date on the later monzodiorite porphyry phase in the Lenshuigou deposit.Two samples were selected for molybdenite ICP-MS Re-Os isotopic analyses from the Lengshuigou granodiorite porphyry,yielding Re-Os model ages from 149.2±2.7 Ma to 150.6±3.4 Ma, with a weighted mean age of 149.7±2.1 Ma.These mineralization ages overlap rock-forming ages of the host intrusions within the error range.This implies that the mineralization occurred in the Late Jurassic,which belongs to the tectonic phase B event of the Yanshan Movement,not Cretaceous as previously thought.Therefore,the Late Jurassic mineralization of the Zhashui-Shanyang district could be connected to the large-scale Yanshan molybdenum metallogenic period,the geodynamic regime of which is attributable to the far field response of convergence of surrounding plates,perhaps the approximately westward subduction of the Izanagi plate beneath the Eurasian continent.

西南三江北段纳日贡玛铜钼矿床地质特征与成矿模式

纳日贡玛铜钼矿床是位于三江成矿带的大型铜(钼)矿床。虽然该矿床在找矿工作上取得重大突破,但关于矿床成矿模式的理论研究较少。在总结矿床地质特征的基础上,对矿区内花岗斑岩的矿物岩石化学成分、微量元素和稀土元素特征进行分析,测试包裹体均一温度、盐度、化学成分及C、H、O同位素组成,探讨其热液蚀变类型及分带特征。结果表明:该矿床为斑岩型铜钼矿床,其成矿物质主要来源于花岗斑岩体,成矿流体为岩浆水和大气降水组成的混合热液。在此基础上,提出了纳日贡玛铜钼矿床的成矿模式,利用Micromine软件建立了矿床三维立体模型,其成果为矿床成因的认识与找矿工作提供了参考。

青海纳日贡玛斑岩钼(铜)矿床：岩石成因及构造控制

初步矿产普查评价成果表明,三江北段已初步显示出巨大的成矿潜力。在该区东部,以纳日贡玛-陆日格含矿斑岩体为中心的斑岩-矽卡岩大型成矿系统已初露端倪。纳日贡玛,作为该区的最具代表性的斑岩型矿床,了解其含矿斑岩的性质,查明斑岩的可能源区,厘定其与玉龙铜矿带的关系,具有重要的理论与现实意义。为此,本文对纳日贡玛矿区出露的主要斑岩体开展了详细的年代学、岩石地球化学及 Sr-Nd—Pb 同位素地球化学研究,结果表明:纳日贡玛主含矿斑岩锆石 U-Pb 年龄为43.3±0.5Ma,明显为玉龙斑岩铜矿带的北延;其主含矿斑岩为高钾钙碱性系列,高度演化的斑岩为钾玄岩系列,岩浆源区可能为50～80km 处壳幔过渡带,经历了明显的流体交代;与玉龙铜矿带含矿斑岩相比,纳日贡玛斑岩钾含量偏低,Sr-Nd—Pb同位素组成更向亏损地幔靠拢,反映岩浆源区自 NW 至 SE 地壳组分逐渐增多和/或流体交代逐渐增强。自纳日贡玛至玉龙带,成矿斑岩的结晶年龄逐渐变新,说明斑岩的形成不仅具有统一的源区,可能受控于统一的动力学机制,因印度-亚洲大陆碰撞产生的始新世右行断裂系统,可能是控制区域岩浆上侵及时空分布的动力学机制。纳日贡玛带矿床矿化以 Mo 为主,显著不同于玉龙带的 Cu-Mo(-Au)矿化组合,造成区域上矿化组合的差异即可因深部过程,也可因岩浆就位后的结晶分异过程,更多的证据显示可能受后者控制明显;因此,纳日贡玛矿床可能遭受了较强的剥蚀。区内应加强斑岩侵位较深时形成的斑岩钼矿及夕卡岩型矿床的寻找。

三江北段纳日贡玛斜长花岗斑岩的年代学及地质意义

纳日贡玛斑岩产于三江北段，由大小不同的6个斑岩体组成，岩石化学显示属于高钾钙碱性系列岩石；稀土配分型式为几乎不具负Eu异常的轻稀土富集型。笔者利用锆石U—Pb方法首次测得纳日贡玛斜长花岗斑岩的生成年龄为41．0±0．18Ma，属喜马拉雅早期。从区域构造演化的角度来看，三江北段大部分花岗质岩体的形成都与喜马拉雅造山作用过程中的岩浆侵位相关，表现为多数同位素年龄都集中在21～66Ma。鉴于纳日贡玛铜钼矿产于纳日贡玛斑岩体中，属于斑岩型，花岗斑岩体为纳日贡玛铜钼矿提供了成矿物质来源。同时三江北段发育较多的中酸性岩体，纳日贡玛铜钼矿床成岩年龄的确定对于在该区寻找斑岩型铜钼矿有重要的理论和现实意义。

纳日贡玛斑岩钼铜矿床：玉龙铜矿带的北延--来自辉钼矿Re-Os同位素年龄的证据

纳日贡玛钼(铜)矿床位于西南"三江"北段青海南部地区,构造上位于金沙江缝合带与班公湖-怒江缝合带所夹持的羌塘地体之上,该区是吸纳和调节印度-亚洲大陆碰撞应力应变的构造转换带;受印度-亚洲大陆斜向碰撞事件的影响,区内新生代构造变形异常复杂,至51Ma 以来,区内形成了一系列 NW-SE 向的逆冲断裂系统及走滑断裂系统,并伴有少量钾质岩浆活动;纳日贡玛斑岩钼(铜)矿床便产于新生代黑云母花岗斑岩及其接触带中。长期以来,由于缺少可靠的年代学数据,人们对纳日贡玛矿床的产出环境尚不清楚,与玉龙癍岩铜矿带的关系还比较模糊。为此,本文选取了纳日贡玛钼铜矿6件辉钼矿样品进行 Re-Os 同位素测年,结果给出了一条均方差为0.79的 Re-Os 等值线,其年龄为40.86±0.85Ma,这与玉龙斑岩铜矿代的成矿年龄基本一致,应为玉龙铜矿带的北延;较大的成矿带延长范围表明,在玉龙至纳日贡玛上千公里的范围内,仍有寻找大型斑岩铜(钼)矿床的巨大潜力。

纳日贡玛含矿斑岩体形成机制及其成矿模式分析

通过系统研究纳日贡玛含矿斑岩体的地质、地球化学特征,深入剖析了含矿斑岩体的形成机制及其成矿模式。研究结果表明,纳日贡玛含矿斑岩体与藏东玉龙含矿斑岩体同属一个成矿带,是喜玛拉雅运动第一幕(40～35Ma)的产物。斑岩体主体部分是黑云母二长花岗斑岩,少部分为花岗闪长斑岩,围岩为中二叠世尕笛考组(P2gd)的玄武岩。含矿斑岩为同源岩浆经长期演化、多期侵位而形成的复式岩体,它们多沿区域性断裂呈串珠状断续分布。斑岩体的内外接触带以及各种裂隙是主要矿体的产出部位。岩体侵入后,由于热重力扩散作用和Cu、Mo元素化学性质的差异,导致成矿元素在空间分布上具有分带性,并且显示出下部富钼、上部富铜的分布特征。研究结果对于深入认识该区的成矿地质条件、成矿规律和指导下一步勘探均具有重要的参考价值。

青藏高原北羌塘盆地纳日贡玛铜钼矿床地质特征及控矿条件

纳日贡玛铜钼矿床属斑岩型铜矿,处于班公湖-怒江缝合带北侧、金沙江缝合带以南的羌北-昌都地块,与玉龙斑岩铜矿床同属一个成矿带。早中二叠世尕笛考组为主要赋矿地层,铜矿体主要产于靠近斑岩体上部的硅化绢云母化黑云母二长花岗斑岩和接触带部位的蚀变玄武岩中,形态复杂,矿石类型较简单。钼矿主要产于斑岩体内具弱蚀变的黑云母二长花岗斑岩、浅色花岗闪长斑岩和强蚀变的硅化绢云母化黑云母二长花岗岩斑岩中,少量分布于黄铁矿青磐岩化玄武岩中,沿走向及倾斜方向延伸比较稳定。矿石类型以细脉浸染型铜钼矿为主,其来源于陆内碰撞而加厚的下地壳。复合断裂是控制本区斑岩成矿带的主要因素,铜钼矿床即产于大断裂交汇部位。中酸性侵入体是内在控矿因素,裂隙构造系统也具有重要的控矿作用。

青海纳日贡玛斑岩型Cu–Mo矿床遥感蚀变异常提取与找矿预测

青海三江北段是我国重要的多金属成矿区带,具有形成大型、特大型金属矿床的赋存条件及地质背景。纳日贡玛矿床是该区带中最为典型的斑岩型Cu–Mo矿床。针对斑岩型矿床的典型蚀变分带特征,利用ASTER数据,采用Crosta技术和比值法进行高岭石化、青磐岩化、黄铁矿化和硅化等遥感蚀变异常信息的提取;通过对ASTER和QuickBird图像的遥感解译,获得花岗斑岩体和断裂构造的空间分布图;根据纳日贡玛矿床的成矿规律和控矿要素,利用遥感数据获得的找矿预测因子,圈定了8个具有良好找矿前景的遥感找矿预测区,并总结出纳日贡玛的遥感蚀变异常分带规律,可为三江北段成矿带中其他斑岩型Cu–Mo矿床的找矿勘查提供重要参考信息。

纳日贡玛斑岩型铜钼矿与玉龙斑岩铜矿成矿特征对比研究

纳日贡玛斑岩型铜钼矿床是西南三江地区继玉龙特大型斑岩铜矿之后发现的又一大型矿床。在总结矿床地质特征的基础上,对两处矿床的含矿斑岩体——花岗斑岩的岩石学、地球化学和成矿时代等特征进行了全面的对比分析,认为纳日贡玛和玉龙斑岩铜矿的成矿特征、成矿时代和成矿环境相似。

纳日贡玛铜钼矿床中流熔包裹体的发现及其意义

纳日贡玛铜钼矿床矿物中包裹体丰富、类型多样,有晶质熔体包裹体、流熔包裹体和流体包裹体三大类。其中,流体包裹体又分气体包裹体、液气包裹体、气液包裹体、含金属矿物或石盐子晶的气液包裹体。对流体包裹体的研究表明,该矿床是在较浅的地质环境中形成的,成矿温度主要为246℃～300℃,盐度最高为31.3wt%～42.2wt%NaCl,而且其矿体均产于高盐度包裹体分布的范围内,并且流体成份以Na+、Cl-和H2O为主。在含矿斑岩的石英中发现了流熔包裹体,这是一种岩浆～热液过渡性流体存在的直接证据,该证据说明了纳日贡玛铜钼矿床是花岗斑岩在演化过程中分异出来的,由岩浆热液形成。

青南纳日贡玛斑岩型铜钼矿床物化探异常特征及找矿模型

纳日贡玛地区位于青海南部高寒山区,自21世纪初国土资源大调查以来该区斑岩型矿床找矿取得了较大的进展,发现了一系列铜钼矿床(点),而常规的物化探综合方法在找矿勘查中发挥了重要作用。本区以纳日贡玛铜钼矿为典型矿床,在总结地质、物探、化探等特征指示标志的基础上,建立了该区斑岩型铜钼矿床的地质—物化探找矿勘查模型。该模型在外围找矿预测中取得了良好的应用效果,圈定了12处找矿靶区,部分靶区经工程验证已发现斑岩型铜钼矿体,找矿前景良好。

青海纳日贡玛斑岩铜(钼)矿地质地球化学特征及成因探讨

纳日贡玛斑岩铜矿,矿体主要赋存在喜山期花岗斑岩体中.笔者通过野外观察和室内研究,从矿床地质特征,岩石地球化学特征等方面对矿床的成因进行了探讨,初步认为它是一个典型的斑岩型铜(钼)矿床.