云南格咱岛弧斑岩-矽卡岩铜、钼（金）矿床成矿系统

格咱岛弧带是西南三江多岛弧盆系中一个主要的地质构造单元,它始于晚三叠世甘孜—理塘洋壳的向西俯冲,燕山期经历了陆内汇聚和造山后伸展作用阶段,区内岩浆活动和成矿作用强烈,是近年来新发现的重要铜多金属成矿带。根据区内岩浆岩和矿床的时空分布,同位素年代学证据,构造环境及成矿作用,将格咱岛弧成矿系统划分为印支期成矿亚系统和燕山期成矿亚系统。印支期主要发育了与安山岩同源的壳幔型中酸性岩浆作用,形成斑岩型Cu矿成矿系统,燕山期伴随着同碰撞中酸性岩浆活动形成斑岩型Mo(Cu)及热液型W(Mo)成矿系统。研究表明,格咱岛弧深部找矿具有较好的资源潜力,其中燕山期Mo多金属成矿已显现出良好的找矿前景。     

Metallogenesis related to Mesozoic Granitoids in the Nanling Range, South China and Their Geodynamic Settings

Affected by the compressive stress from the South-Central （Indo-China） Peninsula, the Indosinian orogenesis, characterized by collision, thrust and uplifting, took place inside the South China Plate during 250-230 Ma. The ages of the Indosinian granitoids in the Nanling Range and vicinity areas are mostly 240-205 Ma, indicating that they were emplaced in both late collision and post-collision geodynamic environments. No important granite-related metallogenesis occurred in this duration. A post-orogenic setting started at the beginning of the Yanshanian Period, which controlled large-scale granitic magmatism and related metallogenesis. This paper makes the first attempt to divide the Yanshanian Period into three sub-periods, i.e. the early, middle and late Yanshanian Periods, based mainly on the features of magmatism, especially granitoids and related metallogenesis and their geodynamic environments. The magmatic association of the Early Yanshanian （about 185-170 Ma） comprises four categories of magmatism, i.e. basalt, bimodal volcanics, A-type granite and intraplate high-K calc-alkaline （HKCA） magmatism, which indicates an extension-thinning of lithosphere and upwelling of mantle material to a relative small and local extent. Pb-Zn, Cu and Au mineralizations associated with HKCA magmatism represents the first high tide of Mesozoic metallogenesis in the Nanling Range area. During the middle Yanshanian, the lithosphere was subjected to more extensive and intensive extending and thinning, and hence mantle upwelling and basaltic magma underplating caused a great amount of crust remelting granitoids. This period can be further divided into two stages. The first stage （170-150 Ma） is represented by large-scale emplacement of crust remelting granites with local tungsten mineralization at its end. The second stage （150-140 Ma） is the most important time of large-scale mineralizations of non-ferrous and rare metals, e.g. W, Sn, Nb-Ta, Bi, Mo, Be, in the Nanling Range area. The late Yanshanian （140-65 Ma） was generally characterized by full extension and breakup of the lithosphere of South China. However, owing to the influence of the Pacific Plate movement, the eastern part of South China was predominated by subduction-related compression, which resulted in magmatism of calc-alkaline and shoshonite series and related metallogeneses of Au, Ag, Pb-Zn, Cu and （Mo, Sn）, followed by extension in its late stage. In the Nanling Range area, the late Yanshanian magmatism was represented by granitic volcanic-intrusive complexes and mafic dikes, which are genetically related to volcanic-type uranium and porphyry tin deposits, and the mobilization-mineralization of uranium from pre-existing Indosinian granites.     

U–Pb and Re–Os Geochronology of the Hucunnan Copper–Molybdenum Deposit in Anhui Province,Southeast China,and its Geological Implications

The Middle–Lower Yangtze Region (MLYR) is one of the most important metallogenic belts in China that hosts numerous Cu–Fe–Au–S deposits. The Hucunnan deposit in the central part of MLYR is a newly discovered porphyry–skarn‐type copper–molybdenum deposit during recent drilling exploration. Laser ablation ICP–MS analysis carried out in this study yields U–Pb isotopic ages of 137.5 ± 1.2 Ma for the Cu–Mo bearing granodiorite rock and 125.0 ± 1.5 Ma for the Cu‐bearing quartz diorites. The Re–Os isotopic dating of seven molybdenite samples gave an isochron age of 139.5 ± 1.1 Ma, suggesting a syn‐magma mineralization of molybdenite in the Hucunnan deposit. Since porphyry‐type molybdenum deposits are rare in central MLYR, the discovery of the Hucunnan deposit suggests possible molybdenite mineralizations in the deep places of the Cu–Mo bearing granitoids. In addition, the U–Pb isotopic age of 125 Ma for the Cu‐bearing quartz diorites implies a new Cu mineralization period for the MLYR that was rarely reported by previous studies.     

The Late Early Cretaceous Mo Mineralization in the South China Mo Province: Constraints from U–Pb and Re–Os Geochronology of the Lufeng Porphyry Mo Deposit

Compared to other Mo provinces, few studies focused on the South China Mo Province(SCMP), especially for Early Cretaceous Mo mineralization. The Lufeng porphyry Mo deposit in the SCMP is characterized by disseminated and veinlet-type mineralization in granite porphyry, gneiss, and rhyolite. In this study, six molybdenite samples yield a Re–Os isochron age of 108.0±1.8 Ma, which is consistent with the zircon U–Pb age of the granite porphyry(108.4±0.8 Ma). The coincidence of magmatic and hydrothermal activities indicates that Mo mineralization was associated with the intrusion of granite porphyry during the late Early Cretaceous. A compilation of U–Pb and Re–Os chronological data suggests that an extensive and intensive Mo mineralization event occurred in the SCMP during the late Early Cretaceous. The marked difference in molybdenite Re contents between Cu-bearing(85–536 ppm) and Cu-barren(1.3–59 ppm) Mo deposits of the late Early Cretaceous indicates that the ore-forming materials were derived from strong crust–mantle interactions. Together with regional petrological and geochemical data, this study suggests that late Early Cretaceous Mo mineralization in the SCMP occurred in an extensional setting associated with the roll-back of the Paleo-Pacific slab.     

Zircon U–Pb,Molybdenite Re–Os and K‐feldspar 40Ar/39Ar Dating of the Bolong Porphyry Cu–Au Deposit,Tibet, China

The Bolong porphyry Cu–Au deposit is a newly discovered deposit in the central Tibetan Plateau, and is ranked as the second largest copper deposit discovered to date in the Bangong‐Nujiang metallogenic belt in China. Three granodiorite porphyry phases occur within the Bolong porphyry Cu–Au deposit. Phyllic alteration is widespread on the surface of the deposit, and potassic alteration occurs at depth, associated with granodiorite porphyries. The copper and gold mineralization is clearly related to the potassic and phyllic alteration. Multiple chronometers were applied to constrain the timing of magmatic–hydrothermal activity at the Bolong deposit. Zircon U–Pb geochronology reveals that the granodiorite porphyry phases were emplaced at ca. 120 Ma. Re–Os data of four molybdenite samples from quartz–molybednite veinlets yielded an isochron age of 119.4 ± 1.3 Ma. The plateau age of hydrothermal K‐feldspar from the potassic alteration zone, analyzed by ⁴⁰Ar/³⁹Ar dating, is 118.3 ± 0.6 Ma, with a similar reverse isochron age of 118.5 ± 0.7 Ma. Therefore, the magmatic–hydrothermal activity occurred at ca. 120–118 Ma, which is similar in age to the neighboring Duobuza porphyry copper deposit. The period of 120–118 Ma is therefore important for the development of porphyry Cu–Au mineralization in the central Tibetan Plateau, and these porphyry deposits were formed during the final stages of the northward subduction of the Neo‐Tethys Ocean.     

Geochronology of the Limu W–Sn–Nb–Ta‐Bearing Granite Pluton in South China

Limu W–Sn–Nb–Ta mining district is located in the Nanling Range W–Sn poly‐metallic mineralization belt in south China. The district includes a number of Sn–Nb–Ta and W–Sn ore occurrences; all of them are spatially associated with granite stocks of a largely‐unexposed pluton, the Limu granitic pluton. A granite sample collected from the Sn–Nb–Ta‐bearing Jinzhuyuan granite stock yields a zircon SHRIMP U–Pb age of 218.3 ± 2.4 Ma, a muscovite ⁴⁰Ar/³⁹Ar plateau age of 212.4 ± 1.4 Ma, and a muscovite ⁴⁰Ar/³⁹Ar isochron age of 213.2 ± 2.2 Ma. Another granite sample collected from the W–Sn‐bearing Sangehuangniu granite stock yields a zircon SHRIMP U–Pb age of 214 ± 5 Ma. The geochronological data provide new constraints on the age of the Limu granite pluton and the timing of the associated W–Sn–Nb–Ta mineralization—at least it sets a reasonable upper age limit for the mineralization of the W–Sn–Nb–Ta ores. The reported ages suggest an active Late Triassic granitic magmatism in Limu area which is part of a regional magmatic event near the end of the Indosinian orogeny in south China.     

Indo–Chinese Magmatic Activity in the Duobaoshan District of Heilongjiang Province and Its Geological Significance

The Duobaoshan ore concentration area, located in Nenjiang County of Heilongjiang Province, is an important porphyry Cu-Mo ore concentration area in China, which is characterized by complex magmatic activities and multi–phase overprinting metallogenesis. On the basis of field geological observation, systematic sampling, in-lab analysis and the metallogenic regularity in the Xiang'an–Mongolian metallogenic belt, this work carried out high-precision dating and geochemical analysis on the Yuejin, 173-kilometer and Wolihedingzi rock bodies. These rock bodies are renamed monzonitic granite and their consistent age(238 Ma) show that they were formed not in Variscan but in Indosinian. Therefore, it is inferred that the ore spots formed in the potassium silicate and sericite alteration zones of the rock mass also belong to Indosinian. In addition, we collected granodiorite from the Tongshan mining pit, and its zircon age is 223.1±2.8 Ma and the Cu content of the sample is high. The Tongshan mineralization is inferred to undergo the superimposition of Indosinian diagenetic mineralization. The age of the granodiorite porphyry related to copper-molybdenum mineralization in the Xiaoduobaoshan area is 222.1±5.5 Ma, and the earlier age of granodiorite is 471.8±7.4 Ma, indicating that the initial magmatic activities belong to the Duobaoshan porphyry system in the Caledonian period. The geochemical characteristics of the Indosinian rock samples show continental arc features, with reference to tectonic-magmatic activities of the whole Daxing'anling area. We consider that the magmatic activities and mineralization of the Indosinian period are affected by the southward subduction of Okhotsk Ocean since Late Permian. By combining the mineralization rules of Daxinganling area and the structural systems of Duobaoshan ore concentration area, we divide two rock-mineralization belts in this area including the Yuejin–Duobaoshan–Tongshan belt and 173-kilometer–Xiaoduobaoshan–Wolihedingzi belt, which are distributed nearly parallel along the NW-trending fractures and show similar geotectonic settings and the timing of the magmatic activities. It is favorable for discovering porphyry Cu-Mo deposits in these two metallogenic belts, especially in the Yuejin, 173-kilometer and Wolihedingzi areas where less research work has been made.     

Chronology of the Tungsten Deposits in Southern Jiangxi Province,and Episodes and Zonation of the Regional W‐Sn Mineralization – Evidence from High‐precision Zircon U‐Pb,Molybdenite Re‐Os and Muscovite Ar‐Ar Ages

Previous studies have obtained some petrogenetic and metallogenic chronological data with SHRIMP (sensitive high-resolution ion microprobe) zircon U-Pb, zircon LA-ICPMS (laser-ablation–inductively coupled plasma mass spectroscopy) U-Pb, molybdenite Re-Os isochron and muscovite Ar-Ar methods in southern Jiangxi Province and its adjacent areas. Based on these, the purpose of this paper is to study the petrogenetic and metallogenic ages and their time gap for different genetic types of W-Sn deposits, and thus to research their numerous episodes, zonal arrangement and their geodynamic background. The result shows that the large-scale W-Sn mineralization in southern Jiangxi Province occurred in the middle to late Jurassic (170–150 Ma), the skarn W-Sn-polymetallic deposits formed much earlier (170–161 Ma), and all of the wolframite – quartz vein type, greisen type, altered granite type and fractured zone type tungsten deposits formed in the late Jurassic (160–150 Ma). In one ore field or ore district, greisen type tungsten deposits formed earlier than quartz vein type ones hosted in the endo- or exo-contact zone; and quartz vein type hosted in the endocontact zone formed earlier than that of exocontact zone. There is no significant time difference between tungsten-tin mineralization and its intimately associated parent granite emplacement (1–6 Ma). They all formed in the same rock-forming and ore-forming system and under the same geodynamic setting. Regionally, rock-forming and ore-forming processes of the W-Sn deposits in the Nanling region (include southern Jiangxi Province, southern Hunan Province, northern Guangdong Province and eastern Guangxi Zhuang Autonomous Region) exhibit numerous episodes. The mineralization in the Nanling region mainly occurred at (240–210) Ma, (170–150) Ma and (130–90) Ma. The tungsten-tin deposits in this region are centered by the largest scale in southern Jiangxi Province and southern Hunan Province, and become small in the east, west, south and north directions. This displays a zonal arrangement and temporal and spatial distribution regularity. Integrated with the latest research results, it is concluded that the W-Sn mineralization in southern Jiangxi Province and its adjacent areas corresponds to the second large-scale mineralization in South China. The Indosinian W-Sn mineralization formed under the extensional tectonic regime between collisional compressional stages, while the Yanshanian large-scale petrogenetic and metallogenic processes occurred in the Jurassic intraplate extensional geodynamic setting of lithosphere extension.     

Study of late-Mesozoic magmatic rocks and their related copper-gold-polymetallic deposits in the Guichi ore-cluster district,Lower Yangtze River Metallogenic Belt,East China

ABSTRACT

The Guichi ore-cluster district in the Lower Yangtze River Metallogenic Belt hosts extensive Cu–Au–Mo polymetallic deposits including the Tongshan Cu–Mo, Paodaoling Au, Matou Cu–Mo, Anzishan Cu–Mo, Guilinzheng Mo and Zhaceqiao Au deposits, mostly associated with the late Mesozoic magmatic rocks, which has been drawn to attention of study and exploration. However, the metallogenic relationship between magmatic rocks and the Cu–Au-polymetallic deposits is not well constrained. In this study, we report new zircon U–Pb ages, Hf isotopic, and geochemical data for the ore-bearing intrusions of Guichi region. LA-ICP-MS U–Pb ages for the Anzishan quartz diorite porphyrite is 143.9 ± 1.0 Ma. Integrated with previous geochronological data, these late Mesozoic magmatic rocks can be subdivided into two stages of magmatic activities. The first stage (150–132 Ma) is characterized by high-K calc-alkaline intrusions closely associated with Cu–Au polymetallic ore deposits. Whereas, the second stage (130–125 Ma) produced granites and syenites and is mainly characterized by shoshonite series that are related to Mo–Cu mineralization. The first stage of magmatic rocks is considered to be formed by partial melting of subducted Palaeo-Pacific Plate, assimilated with Yangtze lower crust and remelting Meso-Neoproterozoic crust/sediments. The second stage of magmatism is originated from partial melting of Mesoproterozoic-Neoproterozoic crust, mixed with juvenile crustal materials. The depression cross to the uplift zone of the Jiangnan Ancient Continent forms a gradual transition relation, and the hydrothermal mineralization composite with two stages have certain characteristics along the regional fault (Gaotan Fault). Guichi region results from two episodes of magmatism probably related to tectonic transition from subduction of Palaeo-Pacific Plate to back-arc extensional setting between 150 and 125 Ma, which lead to the Mesozoic large-scale polymetallic mineralization events in southeast China.     

U–Pb and Re–Os Geochronology of the Tongcun Molybdenum Deposit and Zhilingtou Gold‐Silver Deposit in Zhejiang Province,Southeast China,and Its Geological Implications

Mesozoic ore deposits in Zhejiang Province, Southeast China, are divided into the northwestern and southeastern Zhejiang metallogenic belts along the Jiangshan–Shaoxing Fault. The metal ore deposits found in these belts are epithermal Au–Ag deposits, hydrothermal‐vein Ag–Pb–Zn deposits, porphyry–skarn Mo (Fe) deposits, and vein‐type Mo deposits. There is a close spatial–temporal relationship between the Mesozoic ore deposits and Mesozoic volcanic–intrusive complexes. Zircon U–Pb dating of the ore‐related intrusive rocks and molybdenite Re–Os dating from two typical deposits (Tongcun Mo deposit and Zhilingtou Au–Ag deposit) in the two metallogenic belts show the early and late Yanshanian ages for mineralization. SIMS U–Pb data of zircons from the Tongcun Mo deposit and Zhilingtou Au–Ag deposit indicate that the host granitoids crystallized at 169.7 ± 9.7 Ma (2σ) and 113.6 ± 1 Ma (2σ), respectively. Re–Os analysis of six molybdenite samples from the Tongcun Mo deposit yields an isochron age of 163.9 ± 1.9 Ma (2σ). Re–Os analyses of five molybdenite samples from the porphyry Mo orebodies of the Zhilingtou Au‐Ag deposit yield an isochron age of 110.1 ± 1.8 Ma (2σ). Our results suggest that the metal mineralization in the Zhejiang Province, southeast China formed during at least two stages, i.e., Middle Jurassic and Early Cretaceous, coeval with the granitic magmatism.     

华南地区三叠纪矿床地质特征、成矿规律和矿床模型

华南以中生代成矿大爆发为特征,燕山期矿床成矿规律的研究程度较高,近年来发现越来越多的三叠纪矿床,但三叠纪矿床的分布规律和矿床模型是值得关注的重要科学问题。本文基于最新研究成果,论述华南三叠纪矿床地质特征和矿床类型,提出成矿规律,初步地建立成矿动力学模型。华南地区三叠纪矿床分布较为广泛,目前确定的46个三叠纪矿床分布于5个区带,形成于晚三叠世 (230~200 Ma),被划分为花岗岩有关的钨锡多金属矿床、侵入岩有关的远端金锑矿床、卡林型金矿床和MVT型铅锌矿床4种主要类型。在空间上,华南三叠纪矿床存在成矿元素分带性,由西向东依次为MVT型铅锌矿床、卡林型金矿床、侵入岩有关的远端金锑矿床、花岗岩有关的钨锡多金属矿床。华南5个成矿区带普遍存在印支期和燕山期的叠加成矿作用,在南岭西段桂北苗儿山—越城岭和滇东南老君山地区还发育加里东和印支期的叠加成矿作用。     

Ages and geodynamic settings of Xilamulun Mo–Cu metallogenic belt in the northern part of the North China Craton

The Xilamulun belt along the northern part of the North China Craton is located in eastern segment of the Central Asian Orogenic Belt and has great economic potential for Mo–Cu mineralization. More than ten medium to large ore deposits have been discovered in this region in the recent years. The major types of mineralization type include porphyry (Chehugou Mo–Cu, Kulitou Mo–Cu, Xiaodonggou Mo and Jiguanshan Mo), quartz vein (Nianzigou Mo, Xinjing Mo), epithermal (Hongshanzi Mo–U) and alteration assemblage (Liulingou Mo). The timing of mineralization was previously thought to be Yanshanian (208–290 Ma), however, Indosinian (260–208 Ma) ages for intrusions and mineralization have been recognized in recent years. Based on geochronologic data and regional geological evidence, it is suggested that the mineralization in the Xilamulun belt was formed during multiple events. The mineralization processes are related to a post-collisional extension stage (~ 258–210 Ma) with the generation of the porphyry molybdenum–copper deposit, a tectonic stress transformation from NS to EW (~ 185–150 Ma) that gave rise to vein or porphyry molybdenum deposit, and a lithospheric thinning stage (~ 140–110 Ma) with porphyry molybdenum deposit.     

Re–Os and U–Pb geochronology of porphyry Mo deposits in central Jilin Province: Mo ore-forming stages in northeast China

Central Jilin Province lies along the eastern edge of the Xing–Meng orogenic belt of northeast China. At least 10 Mo deposits have been discovered in this area, making it the second-richest concentration of Mo resources in China. To better understand the formation and distribution of porphyry Mo deposits in the area, we investigated the geological characteristics of the deposits and applied zircon U–Pb and molybdenite Re–Os isotope dating to constrain the age of mineralization. Our new geochronological data show the following: the Jidetun Mo deposit yields molybdenite Re–Os model ages of 164.6–167.1 Ma, an isochron age of 168 ± 2.5 Ma, and a weighted mean model age of 165.9 ± 1.2 Ma; the Houdaomu Mo deposit yields molybdenite Re–Os model ages of 167.4–167.7 Ma, an isochron age of 168 ± 13 Ma, and a weighted mean model age of 167.5 ± 1.2 Ma; and the Chang’anpu Mo deposit yields a zircon U–Pb age for granodiorite porphyry of 166.9 ± 1.5 Ma (N = 16). These new age data, combined with existing molybdenite Re–Os dates, show that intense porphyry Mo mineralization was coeval with magmatism during the Middle Jurassic (167.8 ± 0.4 Ma, r > 0.999). The geotectonic mechanisms responsible for Mo mineralization were probably related to subduction of the Palaeo-Pacific plate beneath the Eurasian continent. Combining published molybdenite Re–Os and zircon U–Pb ages for northeast China, the Mo deposits are shown to have been formed during multiple events coinciding with periods of magmatic activity. We identified three phases of mineralization, two of which had several stages: the Caledonian (485–480 Ma); the Indosinian comprising the Early–Middle Triassic (248–236 Ma) and Late Triassic (226–208 Ma) stages; and the Yanshanian phase comprising the Early–Middle Jurassic (202–165 Ma), Late Jurassic–early Early Cretaceous (154–129 Ma), and Early Cretaceous (114–111 Ma) stages. Although Mo deposits formed during each phase/stage, most of the mineralization occurred during the Early–Middle Jurassic.     

江西大湖塘北段石门寺钨铜钼矿化关系研究

江南造山带中段的赣北大湖塘矿集区是我国近年查明的世界级超大型钨矿产地,并伴生大型铜矿。本文对该区北段石门寺矿区燕山期不同岩石单元的W、Cu、Mo矿化特征与成矿年龄进行了系统研究。白钨矿多呈细脉浸染状产于似斑状花岗岩及其与围岩的外接触带;黄铜矿与辉钼矿多呈浸染状共生于似斑状黑云母花岗岩、细粒黑云母花岗岩、黑云母花岗斑岩及其围岩中。矿石矿物化学研究表明,似斑状黑云母花岗岩、细粒黑云母花岗岩和黑云母花岗斑岩中的硫化物成分较均一,黄铜矿中Cu 34.215%~35.161%、Fe 29.206%~30.721%、S 34.388%~35.520%,辉钼矿中Mo 59.44%~60.54%、S 40.067%~40.370%;似斑状黑云母花岗岩、细粒黑云母花岗岩、黑云母花岗斑岩和石英大脉中的辉钼矿Re-Os同位素模式年龄均值分别为143.3 Ma、145.2 Ma、144.5 Ma、143.6Ma,在误差范围内基本相同,指示该矿区内的Cu、Mo矿化为一期成矿作用形成,由此给出辉钼矿Re-Os同位素等时线年龄145.1±1.0 Ma(MSWD=0.46),代表Cu、Mo矿化时间。结合前人岩浆岩研究结果,石门寺矿区白钨矿与Cu、Mo矿化是两期成矿作用的产物,前者与似斑状黑云母花岗岩密切相关,而后者可能与燕山晚期黑云母花岗斑岩有成因联系,成矿物质由斑岩向其他岩石单元迁移逐渐成矿。     

Re–Os and U–Pb Geochronology of Porphyry and Skarn Types Copper Deposits in Jilin Province,NE China

Jilin Province in NE China lies on the eastern edge of the Xing–Meng Orogenic Belt. Mineral exploration in this area has resulted in the discovery of numerous large, medium, and small sized Cu, Mo, Au, and Co deposits. To better understand the formation and distribution of both the porphyry and skarn types Cu deposits of the region, we examined the geological characteristics of the deposits and applied zircon U–Pb and molybdenite Re–Os isotope dating to constrain the age of the mineralization. The Binghugou Cu deposit yields a zircon U–Pb age for quartz diorite of 128.1 ± 1.6 Ma; the Chang'anpu Cu deposit yields a zircon U–Pb age for granite porphyry of 117.0 ± 1.4 Ma; the Ermi Cu deposit yields a zircon U–Pb age for granite porphyry of 96.8 ± 1.1 Ma; the Tongshan Cu deposit yields molybdenite Re–Os model ages of 128.7 to 130.2 Ma, an isochron age of 129.0 ± 1.6 Ma, and a weighted mean model age of 129.2 ± 0.7 Ma; and the Tianhexing Cu deposit yields molybdenite Re–Os model ages of 113.9 to 115.2 Ma, an isochron age of 114.7 ± 1.2 Ma, and a weighted mean model age of 114.7 ± 0.7 Ma. The new ages, combined with existing geochronology data, show that intense porphyry and skarn types Cu mineralization was coeval with Cretaceous magmatism. The geotectonic processes responsible for the genesis of the Cu mineralization were probably related to lithospheric thinning. By analyzing the accumulated molybdenite Re–Os, zircon U–Pb, and Ar–Ar ages for NE China, it is concluded that the Cu deposits formed during multiple events coinciding with periods of magmatic activity. We have identified five phases of mineralization: early Paleozoic (~476 Ma), late Paleozoic (286.5–273.6 Ma), early Mesozoic (~228.7 Ma), Jurassic (194.8–137.1 Ma), and Cretaceous (131.2–96.8 Ma). Although Cu deposits formed during each phase, most of the Cu mineralization occurred during the Cretaceous.     

Re–Os and U–Pb Geochronology of the Dawan Mo–Zn–Fe Deposit in Northern Taihang Mountains,China

The Dawan Mo–Zn–Fe deposit located in the Northern Taihang Mountains in the middle of the North China Craton (NCC) contains large Mo‐dominant deposits. The mineralization of the Dawan Mo–Zn–Fe deposit is associated with the Mesozoic Wanganzhen granitoid complex and is mainly hosted within Archean metamorphic rocks and Proterozoic–Paleozoic dolomites. Rhyolite porphyry and quartz monzonite both occur in the ore field and potassic alteration, strong silicic–phyllic alteration, and propylitic alteration occur from the center of the rhyolite porphyry outward. The Mo mineralization is spacially related to silicic and potassic alteration. The Fe orebody is mainly found in serpentinized skarn in the external contact zone between the quartz monzonite and dolomite. Six samples of molybdenite were collected for Re–Os dating. Results show that the Re–Os model ages range from 136.2 Ma to 138.1 Ma with an isochron age of 138 ± 2 Ma (MSWD = 1.2). U–Pb zircon ages determined by laser ablation inductively coupled plasma mass spectrometry yield crystallization ages of 141.2 ± 0.7 (MSWD = 0.38) and 130.7 ± 0.6 Ma (MSWD = 0.73) for the rhyolite porphyry and quartz monzonite, respectively. The ore‐bearing rhyolite porphyry shows higher K₂O/Na₂O ratios, ranging from 58.0 to 68.7 (wt%), than those of quartz monzonite. All of the rock samples are classified in the shoshonitic series and characterized by enrichment in large ion lithophile elements; depletion in Mg, Fe, Ta, Ni, P, and Y; enrichment in light rare earth elements with high (La/Yb)_n ratios. Geochronology results indicate that skarn‐type Fe mineralization associated with quartz monzonite (130.7 ± 0.6 Ma) formed eight million years later than Mo and Zn mineralization (138 ± 2 Ma) in the Dawan deposit. From Re concentrations in molybdenite and previously presented Pb and S isotope data, we conclude that the ore‐forming material of the deposit was derived from a crust‐mantle mixed source. The porphyry‐skarn type Cu–Mo–Zn mineralization around the Wanganzhen complex is related to the primary magmatic activity, and the skarn‐type Fe mineralization is formed at the late period magmatism. The Dawan Mo–Zn–Fe porphyry‐skarn ores are related to the magmatism that was associated with lithospheric thinning in the NCC.     

华北克拉通北缘张家口-宣化地区古生代-中生代岩浆构造活动与成矿作用

河北省张家口-宣化地区(张宣地区)位于华北克拉通北缘中段,区内自显生宙以来构造活动频繁,并产出大量岩浆岩和金矿床,是研究华北克拉通北缘岩浆-构造-成矿演化体系的重要对象.本文通过对张宣地区的水泉沟正长岩、响水沟似斑状花岗岩、井儿洼粗安岩-英安岩、象山花岗闪长岩、青羊沟黑云母二长花岗岩和张家口组流纹岩的锆石年龄、Lu-H...     

Geological Characteristics and Metallogenic Setting of Representative Magmatic Cu‐Ni Deposits in the Tianshan‐Xingmeng Orogenic Belt,Central Asia

A great number of magmatic Cu-Ni deposits(including Kalatongke in Xinjiang and Hongqiling in Jilin) are distributed over a distance of almost 3000 km across the Tianshan-Xingmeng Orogenic Belt, from Tianshan Mountains in Xinjiang in the west, to Jilin in eastern China in the east. These deposits were formed during a range of magmatic episodes from the Devonian to the Triassic. Significant magmatic Cu-Ni-Co-PGE deposits were formed from the Devonian period in the Nalati arc(e.g. Jingbulake Cu-Ni in Xinjiang), Carboniferous period in the Puerjin-Ertai arc(e.g. Kalatongke Cu-Ni-Co-PGE in Xinjiang), Carboniferous period in the Dananhu-Touquan arc(e.g. Huangshandong, Xiangshan and Tulaergen in estern Tianshan, Xinjiang) to Triassic period in the Hulan arc(e.g. Hongqiling Cu-Ni in Jilin). In addition to the overall tectonic, geologic and distribution of magmatic Cu-Ni deposits in the Tianshan-Xingmeng Orogenic Belt, the metallogenic setting, deposit geology and mineralization characteristics of each deposit mentioned above are summarized in this paper. Geochronologic data of Cu-Ni deposits indicate that, from west to east, the metallogenic ages in the Tianshan-Xingmeng Orogenic Belt changed with time, namely, from the Late Caledonian(～440 Ma), through the Late Hercynian(300–265 Ma) to the Late Indosinian(225–200 Ma). Such variation could reflect a gradual scissor type closure of the paleo Asian ocean between the Siberia Craton and the North China Craton from west to east.     

Ar–Ar Ages of Hydrothermal Muscovite and Igneous Biotite at the Guposhan–Huashan District,Northeast Guangxi,South China: Implications for Mesozoic W–Sn Mineralization

The Guposhan–Huashan district is an important W–Sn–Sb–Zn–(Cu) metallogenic area in South China. It is located in the middle‐west segment of the Nanling Range. Granitoids in the Guposhan–Huashan district possess certain properties of A‐type or I‐type granites. The W–Sn–Sb–Zn mineralization in the district is closely associated with magma emplacement. Two igneous biotite and seven hydrothermal muscovite samples from skarn, veins and greisenization ores were analyzed by Ar–Ar methods. Two igneous biotite samples from fine‐grained quartz monzodiorite and fine‐grained biotite granite show plateau ages of 168.7 ± 1.9 Ma and 165.0 ± 1.1 Ma, respectively. Seven hydrothermal muscovite samples from ores yield plateau ages as two groups: 165 Ma to 160 Ma and 104 Ma to 100 Ma. These data suggest that the emplacement of fine‐grained granitoids in this district is coeval with the main phase magma emplacement, different from previous studies. The W–Sn–Sb–Zn mineralization took place in two stages, i.e. the Middle–Late Jurassic and early Cretaceous. W–Sn mineralization in the Guposhan–Huashan district is closely related to the magmatism, which was strongly influenced by underplating of asthenospheric mantle along trans‐lithospheric deep faults and related fractures.     

安徽池州许桥—乌古墩铅锌矿石榴子石和锆石U-Pb定年

石榴子石U-Pb定年在限定金属矿床形成时代上具有一定的优越性,而且近年来得到不少成功地应用。作为长江中下游的重要组成部分,池州地区燕山期岩浆活动强烈,伴随有成矿作用。然而,由于矿体赋存于沉积围岩中,区内的铅锌矿化时代目前还很模糊。本次对许桥—乌谷墩铅锌矿中多条岩脉及石榴子石进行多种矿物原位U-Pb定年。乌谷墩矿区内见有两种岩性的岩脉,其一为闪长玢岩,与铜、钼矿化关系密切,锆石U-Pb定年结果为146～141 Ma;另一为细粒花岗岩,与钼矿化关系密切,锆石U-Pb定年结果为113.4±2 Ma。矽卡岩中石榴子石U-Pb定年结果为148～143 Ma,形成时代与闪长玢岩脉一致。根据现有数据,池州地区存在3个阶段的成岩成矿作用：第一阶段（150～135 Ma）,主要形成中酸性侵入岩和与之相关的铜、金、钼、铅、锌等矿床;第二阶段（134～124 Ma）,形成钾长花岗岩和相关的铅锌钼矿化;第三阶段（115～110 Ma）,岩浆活动接近尾声,主要发育花岗岩脉,并伴随弱的钼矿化。结合区域成矿规律,池州地区的成矿作用不完全与长江中下游地区相同,且池州区内的多期Mo （W）矿化可能与中-新元古代增生地壳多阶段活化有关。