Late-Variscan antimony mineralisation in the Rheinisches Schiefergebirge, NW Germany: evidence for stibnite precipitation by drastic cooling of high-temperature fluid systems

Antimony-rich vein mineralisation is widespread in the German part of the Variscan orogenic belt. Mineralogical investigation of a representative suite of these deposits, coupled with fluid inclusion characterisation and microthermometry, permits a reconstruction of their genetic evolution. Two structural settings host antimony mineralisation: the cores or flanks of anticlinal zones and major lithological contrasts. Channelled migration of geothermal fluids through permeable rock sequences and later stagnation of fluids in cap-rock situations inside the anticlinal zones led to mineral deposition. The mineralising event is interpreted as relating to input of deep-sourced fluids during late-orogenic exhumation at the transitional stage between collision tectonics and the late-Variscan extensional regime. Fluid inclusion data, chlorite geothermometry and the presence of meneghinite as a characteristic Pb-Sb-sulfosalt mineral in a number of vein systems allows constraints on model P-T conditions at the onset of mineralisation to be made. These are as high as 390 to 440?°C at 0.6–1.0?kbar for the Saarsegen, Apollo and Schöne Freundschaft deposits, with lower temperatures of 320–340?°C being obtained for the Spes deposit. The fluid inclusion data indicate drastic fluid cooling during the mineralising event; minimum temperatures of approximately 150–220?°C are obtained for all deposits at the end of vein quartz formation, which coincided with deposition of stibnite and most of the Pb-Sb sulfosalts. Besides the formation of extensional quartz-stibnite-Pb-sulfosalt veins, the mineralising, low-salinity NaCl-KCl-rich high-temperature tectonic brines have overprinted sulfide assemblages within earlier siderite-(Cu)-Pb-Zn veins. This has led to replacement reaction textures and remobilisation of sulfide components within the vein systems. In contrast with the earlier siderite-(Cu)-Pb-Zn veins, neither the quartz-stibnite-sulfosalt nor the (Cu)-Pb-Sb sulfosalt assemblages were affected by Variscan deformation. Rather, they display characteristic extensional features crosscutting all earlier structures and can thus be assigned to a later phase of mineralisation. Fluid composition characteristics and structural criteria indicate formation in the latest part of the Variscan mineralisation cycle; a post-Variscan genesis being rejected on grounds of conspicuously diverging fluid characteristics. A comparison of antimony deposits in the Rheinisches Schiefergebirge with other late-orogenic deposits elsewhere in the European Variscan belt indicates a significant number of shared features, enabling them to be placed into a common model related to the onset of late-Variscan brittle extensional tectonics.     

Late orogenic magmatism and sedimentation within Late Carboniferous to Early Permian basins in the Balkan terrane (Bulgaria): geodynamic implications

The orogenic Balkanid belt, which developed between the Moesian Plate and the Moravian-Rhodopi-Thracian Massifs, was affected by the Late Carboniferous and Early Permian opening of W-E oriented graben structures. The progressive tectonic rejuvenation of the basins is demonstrated by the deposition of repeated regional sedimentary cycles, associated with volcanism that was mostly localised along the tectonic boundaries, in an intramontane setting.The Late Carboniferous volcanism is represented by rhyodacitic explosive products and hyaloclastites, and by andesitic flows. During the Early Permian, subvolcanic rhyodacitic and rhyolitic bodies and the explosive products prevailed in the western sectors, whereas rhyolitic ignimbrites occur to the east.The tectonically active basins are interpreted due to late orogenic collapse, and the alternation of extensional tectonics and minor compressional phases is consistent with the regional transtensional regime, active along the Variscan suture of Pangaea. The volcanic activity associated with the evolution of the basins matches the petrogenetic features and the evolution from early dacitic – andesitic to late rhyolitic activity in the Southern European segment of the Variscan system.These Late Carboniferous-Early Permian sedimentary and tectono-magmatic events in Bulgaria are characterized, and compared with the homologous Permo-Carboniferous sequences along some western European segments of the Variscan belt.     

First Permian–Early Triassic zircon ages for tin-bearing granites from the Gemeric unit (Western Carpathians, Slovakia): connection to the post-collisional extension of the Variscan orogen and S-type granite magmatism

This study presents the first preliminary U–Pb zircon data on tin-bearing S-type granites from the Gemeric unit of the Western Carpathians (Slovakia). U–Pb single zircon dating controlled by cathodoluminescence suggests crystallization of the Gemeric granites during Permian to Early Triassic (303–241 Ma) time. Post-crystallization, low-temperature metamorphic overprint is reflected by partial Pb loss in zircons. These Gemeric granites are younger than the highly fractionated, S-type, tin- and rare-element-bearing leucogranites in the European Variscides. They may have resulted from partial melting, triggered by increased heat flow from the mantle below the continental crust, and most probably intruded during the post-collisional extension and initial rifting of the Variscan orogenic belt. During Alpine orogeny, the Gemeric granites were affected by a low-temperature deformation and metamorphism.     

Pseudotachylytes in the Balmuccia peridotite (Ivrea Zone) as markers of the exhumation of the southern Alpine continental crust

Two types of pseudotachylytes are observed in the Balmuccia peridotite of the Ivrea zone (Southern Alps, Italy). A-type pseudotachylytes correspond to previously studied occurrences and were formed under temperatures comprising between 550 and 900 °C and pressures comprising between 0.6 and 1.2 GPa. These conditions were met in the Ivrea crust between 350 and 270 Ma, suggesting that A-type pseudotachylytes were formed during Variscan tectonics or Permian transtensional tectonics. B-type pseudotachylytes post-date A-type pseudotachylytes. Textural characteristics of B-type veins suggest a formation in the upper continental crust, at depths of about 5–10 km or less. Petrological constraints indicate that the exhumation of the Ivrea crust at such shallow depths was achieved later than c.  70 Ma, thus providing a maximum age of 70 Ma for B-type veins. Pseudotachylytes appear as markers of the poly-orogenic evolution of the Alpine belt.     

新疆东天山晚古生代地壳增生和成矿作用

地壳增生和成矿作用是矿床学研究的前沿领域;东天山作为中亚造山带的重要组成部分,在晚古生代地壳演化过程中经历了板块俯冲、碰撞造山大规模走滑剪切和后造山演化阶段,在每个构造演化阶段都伴随有地壳增生和大量有用金属元素的堆积。按照地壳增生和成矿作用关系,研究区晚古生代主要有如下几种矿床类型:1)晚泥盆世—早石炭世增生前形成的Cu-Mo-Au-Ag矿床;2)早石炭世增生前形成的Fe-Cu-Pb-Zn矿床;3)晚石炭世—早二叠世增生后形成的造山型Cu-Ni-PGE矿床;4)晚石炭世—早二叠世增生后形成的造山型Au-Cu矿床。上述矿床在形成过程中既有地壳的水平增生,也有地壳的垂向增生作用,已经构成了我国重要的内生金属矿床富集区。     

三江地区义敦岛弧碰撞造山过程：花岗岩记录

义敦岛弧碰撞造山带是特提斯－喜马拉雅巨型造山带中的一个复合造山带。本文利用义敦岛弧碰撞造山带29个花岗岩体的43件同位素测年数据，结合岩石地球化学特征，建立了造山带花岗岩的时间坐标。初步识别出4套不同成因类型的花岗岩，即印支期弧花岗岩、燕山早期同碰撞花岗岩、燕山晚期A型花岗岩和喜马拉雅期花岗岩。据此，再造了造山带的形成过程与演化历史：印支期的大规模俯冲造山作用（238－210Ma)，形成义敦火山岩浆弧；大约自206Ma始，发生弧－陆碰撞，伴随岛弧地壳挤压收缩和剪切变形，发育同碰撞花岗岩；进入燕山晚期（138－73Ma)，岛弧碰撞造山带发生造山后伸展作用，形成A型花岗岩带；喜马拉雅期发生陆内造山作用（65－15Ma)，岛弧碰撞造山带出现逆冲－推覆和大规模走滑平移，伴随喜马拉雅期花岗岩的侵位和拉分盆地的形成。     

Middle Carboniferous crustal melting in the Variscan Belt: New insights from U–Th–Pbtot. monazite and U–Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)

In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pb_tot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Anglès, Vialais, Soulié) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthracifères” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.     

A uranium and thorium enriched province of the Fennoscandian shield in southern Norway

The Precambrian Flå, Iddefjord, and Bohus granites lie along a line striking roughly northwest which crosses the Permian Oslo Province to the southwest of Oslo. Radioelement investigations in the three bodies show they all contain abnormally high thorium and uranium concentrations relative to the published literature on average radioelement contents of granitic rocks. Trend surface analysis of the radioelement distribution in the Iddefjord granite suggests there was relative movement of uranium to the east with respect to thorium, possibly as the result of Permian activity in the adjacent rocks. Geological considerations, radiometric evidence and published gravimetric data suggest that the 3 granites represent a continuous belt enriched in thorium and uranium during the Sveconorwegian orogeny. A portion of the belt was later involved in the Permian igneous activity which produced the igneous Oslo Province. There is some evidence that the Permian Drammen and Finnemarka granites represent that part of the belt which was modified in Permian time.     

阿拉善宗乃山岩体东南缘花岗岩LA-ICP-MS锆石U-Pb年龄与地球化学特征

阿拉善宗乃山岩体东南缘分布多种类型的花岗岩,本文主要采用岩相学、激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)锆石U-Pb定年、岩石地球化学等技术手段,对宗乃山岩体东南缘岩石类型、年代学、源岩特征以及构造背景进行了研究。结果表明:岩石类型主要为碱性-钙碱性准铝质花岗岩和闪长岩;单颗粒锆石分析获得黑云母斜长花岗岩年龄为236.8±1.9 Ma~249.7±2.6 Ma,片麻状花岗岩年龄为268.1±1.1 Ma,岩体成岩时期主要为华力西晚期和印支期早期,具有多期侵入的特征。该岩体岩石源岩为I型花岗岩,源于地壳火山弧区和同碰撞区,表明由于洋壳俯冲作用,在宗乃山东南缘形成了岛弧花岗岩侵入体。LA-ICP-MS锆石U-Pb定年技术为洋壳俯冲提供了年代学约束,确定了研究区碰撞时间为早于236.8±1.9 Ma。     

Petrogenesis of multistage S-type granites from the Malay Peninsula in the Southeast Asian tin belt and their relationship to Tethyan evolution

The relationship between plate tectonics and the reworking of continental crust remains controversial. Multistage, hornblende-free, S-type granites across the Malay Peninsula Sn belt are ideal for investigating this research question. Here we present zircon U-Pb ages, in-situ apatite Nd and zircon Hf isotope data, and whole-rock major and trace element data for these S-type granites and spatially associated dykes. Four generations of Permian–Triassic (276–272, 262–260, 231–222, and 202 Ma) S-type granites were identified. The different S-type granites show distinct in-situ zircon Hf and apatite Nd isotopic compositions, implying generation from different sedimentary protoliths. Input of mantle-derived components for the formation of all these S-type granites, further indicating that both continental crustal reworking and growth occurred in the Malay Peninsula during the Permian–Triassic. A 250 Ma dolerite dyke in the Eastern Province was derived from an E-MORB-like mantle source. However, a 202 Ma monzonite dyke in the Western Province, was derived from mafic magmas produced by the melting of enriched mantle, followed by subsequent incorporation of crustal materials. All these S-type granitic magmas were reduced that inherited from sedimentary protoliths, which were favourable for Sn mineralization. Apatite F-Cl concentrations and F/Cl ratios in the S-type granites and related dykes changed systematically through time. We infer that the formation of these S-type granites and related dykes corresponds to the Palaeo-Tethyan evolution (i.e., early subduction of Palaeo-Tethyan oceanic lithosphere and subsequent collision between the Sibumasu and Indochina blocks). Our study also support that multistage S-type granites can be generated in distinct tectonic environments at different times in the same region.     

新疆东天山晚古生代地壳增生和成矿作用

地壳增生和成矿作用是矿床学研究的前沿领域; 东天山作为中亚造山带的重要组成部分,在晚古生代地壳演化过程中经历了板块俯冲、碰撞造山大规模走滑剪切和后造山演化阶段,在每个构造演化阶段都伴随有地壳增生和大量有用金属元素的堆积。按照地壳增生和成矿作用关系,研究区晚古生代主要有如下几种矿床类型： 1）晚泥盆世—早石炭世增生前形成的Cu Mo Au Ag矿床; 2）早石炭世增生前形成的Fe Cu Pb Zn矿床; 3）晚石炭世—早二叠世增生后形成的造山型Cu Ni PGE矿床; 4）晚石炭世—早二叠世增生后形成的造山型Au Cu矿床。上述矿床在形成过程中既有地壳的水平增生,也有地壳的垂向增生作用,已经构成了我国重要的内生金属矿床富集区。     

The Variscan post-collisional volcanism in Late Carboniferous–Permian sequences of Ligurian Alps, Southern Alps and Sardinia (Italy): a synthesis

In the considered wide sector of the West-Mediterranean southern Europe, the collisional phase of the Variscan orogeny during Late Carboniferous and Permian times was followed by magmatic intrusive and effusive activity and sedimentation into intracontinental, alluvial to lacustrine basins originated by wrench- to normal-fault systems. The first volcanic cycle (generally Late Carboniferous-Early Permian in age) is represented by early calc-alkaline andesites and rhyolites, in variable amounts, and by following large volume of rhyolites, and by dacites. Both andesites and rhyolites show K-normal and high-K calc-alkaline character. The origin of the liquids of the first cycle is ascribed to partial melting processes at the mantle–crust interface telescoped within a thickened crust. The melting is considered as the consequence of thermal re-equilibration following isostatic disequilibrium and the subsequent collapse of the orogenic belt; the ascent of liquids occurred in a (trans-)tensional regime. The second magmatic cycle is represented by alkaline magmatism, and exhibits typical anorogenic features consistent with a rifting regime. This event was no more related with the collapse of the Variscan belt, but rather to the post-Variscan global re-organization of plates that evolved during Late Triassic times to the neo-Tethyan rifting. In both cycles, important differences in timing, areal distribution and outpoured volumes arise.     

波密地区帕隆藏布残留蛇绿混杂岩带的发现及其意义

在进行1：25万墨脱幅地质调查中，笔者首次在波密地区发现和填绘出了帕隆藏布残留蛇绿混杂岩带。帕窿藏布残留蛇绿混杂岩呈串珠状产出于花岗岩类侵入岩中，其岩石组合为橄揽辉石岩、辉石岩、辉长岩、辉长辉绿岩、辉绿岩、石英岩和大理岩，局部可见条带状硅质岩。上述组分之间的相互关系表明，蛇绿岩在花岗岩类岩石侵入之前发生过构造混杂和变形。根据沉积岩所记录的盆地演化过程、蛇绿岩的Rb-Sr年龄值以及残留蛇绿混杂岩带两刨花岗岩类岩石的特征和生成时代综合分析认为：帕隆藏布残留蛇绿混杂岩带形成于石炭-二叠纪的弧间盆地中，至少在晚三叠纪之前出现洋壳，在消减过程中向北俯冲并在中侏罗世之前闭合(弧-弧碰撞)。     

Middle Carboniferous crustal melting in the Variscan Belt: New insights from U–Th–Pbtot. monazite and U–Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)

In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pb_tot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Anglès, Vialais, Soulié) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthracifères” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.     

冀北坝上地区深部地质构造特征及其对火山活动和铀成矿的控制作用

冀北坝上地区位于华北地台北缘。其深部地质构造有两个显著特征：一是全区性的莫霍面下拗，地壳增厚；二是软流圈部分伸入到下岩石图上部，造成局部地区地幔上隆，地壳减薄。火山喷发形成的沽源火山盆地和大滩火山盆地与两个地幔上隆，地壳减薄区，上下相互对应。铀矿床（点）沿地幔隆起周边构造活动带规律性分布。上述两事实有力地证明了深部地质构造对中新生代火山活动和铀成矿的控制作用。沿地幔隆起周边构造活动带是今后寻找铀及多金属矿产的有利地段。     

广西十万大山前陆冲断推覆构造

通过十万大山盆地内地震剖面资料和ＴＭ遥感图象的地质构造解译,结合重力资料和野外地质观察及构造分析,阐述了十万大山前陆冲断推覆构造的发育特征和前陆盆地的构造演化。前陆冲断推覆构造由３个不同的构造变形带组成：卷入海西和印支期花岗岩体的逆冲断裂带、充填中生代陆相沉积并发生构造滑脱的前陆盆地和对应于华南准地台的前陆腹地。冲断推覆构造的形成和演化是与中、晚古生代钦州海槽晚二叠世的褶皱回返和中生代相继的构造复活密切联系的,它经历了３期主要构造应力作用事件：晚二叠世海西运动晚幕为冲断推覆构造的雏形期,晚三叠世印支运动晚幕的近ＳＮ向挤压是陆相前陆盆地的发育期;早白垩世末期燕山运动主幕ＮＷ—ＳＥ向挤压是现今十万大山前陆冲断推覆构造的成型期。     

Variscan Sn–W–Mo metallogeny in the gravity picture of the Krušné hory/Erzgebirge granite batholith (Central Europe)

Late Variscan wolframite (± molybdenite) and cassiterite–wolframite greisen, skarn and vein deposits occur in a close spatial association with the granites of the Krušné hory/Erzgebirge batholith (KHEB) in Central Europe. We examined the distribution of the deposits in relation to the gravity field affected by Late Variscan granites using the data from previous gravity and metallogenic studies. Late Variscan granites are differentiated into earlier biotite monzogranites (low-F granites) and later biotite or lithium mica syenogranites (high-F granites) in accordance with the previous classifications. All the outcrops of granites in the KHEB region and their hidden continuation are confined to the Bouguer anomaly contour of − 20 mGal. The Sn–W–Mo (rare metal) deposits and occurrences are within the gravity contour of − 30 mGal with the exception of the Grossschirma stratiform tin deposit in the Freiberg polymetallic ore district. We constructed a geological model based on the gravity data along two profiles across the KHEB showing the position of some rare metal deposits and of outcropping and hidden granite bodies. The models show that the overlapping of earlier and later granites is in the areas of the most intense regional gravity minima. These coincide with the Eastern Volcano-Plutonic Complex (Altenberg minimum), which encloses large volumes of felsic extrusives, microgranite dikes and granites, and the Western Plutonic Complex (Eibenstock minimum), with small volumes of felsic dikes and predominance of earlier and later granites, with no extrusives preserved. There is no distinct relationship between the masses of Late Variscan granites and the distribution and the sizes of associated W ± Mo and Sn–W deposits. We prefer the idea that rare metal mineralization was formed by hydrothermal fluids derived from outside of presently outcropping granites. It originated in two cycles: one connected with the formation of earlier granites producing W ± Mo associations and the other one associated with later granites connected with Sn–W mineralization. Mineralizing fluids were probably generated by mantle–crustal interaction in the crust near the mantle–crust boundary as also indicated by lamprophyric intrusions coeval with the Late Variscan granitic magmatism.     

Rapid Variscan exhumation and the role of magma in core complex formation: southern Brittany metamorphic belt, France

ABSTRACT The high-grade migmatitic core to the southern Brittany metamorphic belt has mineralogical and textural features that suggest high-temperature decompression. The chronology of this decompression and subsequent cooling history have been constrained with ⁴⁰Ar/³⁹ Ar ages determined for multigrain concentrates of hornblende and muscovite prepared from amphibolite and late-orogenic granite sheets within the migmatitic core, and from amphibolite of the structurally overlying unit. Three hornblende concentrates yield plateau isotope correlation ages of c. 303–298 Ma. Two muscovite concentrates record well-defined plateau ages of c. 306–305 Ma. These ages are geologically significant and date the last cooling through temperatures required for intracrystalline retention of radiogenic argon. The concordancy of the hornblende and muscovite ages suggest rapid post-metamorphic cooling. Extant geochronology and the new ⁴⁰Ar/³⁹Ar data suggest a minimum time-integrated average cooling rate between c. 725 °C and c. 125 °C of c. 14 ± 4°C Ma^-1, although below 600 °C the data permit an infinitely fast rate of cooling. Mineral assemblages and reaction textures in diatexite migmatites suggest c. 4 kbar decompression at 800–750 °C. This must have pre-dated the rapid cooling. Emplacement of two-mica granites into the metamorphic belt occurred between 345 and 300 Ma. The youngest plutons were emplaced synkinematically along shallow-dipping normal faults interpreted to be reactivated Eo-Variscan thrusts. A penetrative, west-plunging stretching lineation developed in these granites suggests that extension was orogen-parallel. Extension was probably related to regional uplift and gravitational collapse of thermally weakened crust during constrictional (escape) tectonics in this narrow part of the Variscan orogen. This followed slab breakoff during the terminal stages of convergence between Gondwana and Laurasia; detachment may have been consequent upon a change in kinematics leading to dextral displacement within the orogen. Dextral ductile strike-slip displacement was concentrated in granites emplaced synkinematically along the South Armorican Shear Zone. Rapid cooling is interpreted to have resulted from tectonic unroofing with emplacement of granite along decollement surfaces. The high-grade migmatitic core of the southern Brittany metamorphic belt represents a type of metamorphic core complex formed during orogen-parallel extensional unroofing and regional-scale ductile flow.     

中国东北钼矿床地质

中国东北地区是中亚造山带和环太平洋构造带叠加的区域,成矿作用复杂而强烈。系统总结了东北地区的钼矿床勘查和研究进展,形成如下主要认识：1)研究区已发现3个超大型、18个大型等70余处钼矿床,探明资源量仅次于东秦岭钼矿带;2)矿床成因类型主要为斑岩型（含爆破角砾岩型）、矽卡岩型,次为热液脉型;3)成矿岩浆岩多为高硅富钾钙碱性的I型花岗岩,岩浆活动具有多期多阶段性;4)钼矿床集中分布在华北克拉通北缘、南大兴安岭、北大兴安岭和吉黑褶皱带等4个地区;5)与岩浆活动的多期多阶段性相一致,钼矿化具有多期多阶段性,但中生代最为重要,并集中在250~210、190~160和150~110 Ma等3个高峰期;6)钼矿床的辉钼矿Re含量变化较大,总体较低,显示成矿物质来源复杂,但以壳源为主;7)成矿时代越老,辉钼矿Re含量越高,Cu/Mo储量比越大;8)钼矿床主要形成于增生造山和大陆碰撞造山（含后碰撞）两种构造背景,单钼矿床始现于三叠纪,只形成于大陆碰撞造山体制。     

Carboniferous and Permian granites of the northern Tasman orogenic belt, Queensland, Australia: insights into petrogenesis and crustal evolution from an in situ zircon study

In situ U–Pb dating and Lu–Hf systematics of zircon in granites of the Hodgkinson Province in the northern Tasman orogenic belt, Queensland, Australia, reveal input of isotopically more evolved crustal magmas and larger ranges in ¹⁷⁶Hf/¹⁷⁷Hf in the Carboniferous I-type granites (0.28219–0.28269; weighted average ~0.28245) than in the Permian S-type granites (0.28249–0.28280; weighted average ~0.28262) and Permian I-type granites (0.28253–0.28274; weighted average ~0.28260). The wide range in the Hf-isotope compositions of zircons in the Carboniferous and Permian granites can be explained by remelting of a heterogeneous Mesoproterozoic crustal source, whereas a narrow range reflects the subsequent dissolution of inherited grains/cores and magma homogenisation before zircon crystallisation. Alternatively, mixing between the most radiogenic and unradiogenic magmas can produce the isotopic variation seen in other Carboniferous granites. Remelting of Neoproterozoic average crust or mafic younger crust can produce the more radiogenic Hf-isotope compositions of zircons in the Permian S-type granites. An overlap between the Hf-isotope signatures of the Carboniferous I-type granites in the southwestern Hodgkinson Province and the northeastern Australian craton (0.28211–0.28254) and evidence for major magmatic events at 1,585–1,545 and 345–300 Ma imply that the southwestern province is underlain by cratonic crust, which wedges out towards the northeast. The more radiogenic Hf-isotope signature of the Permian granites and a lack of evidence for these major magmatic events in the southeastern and central Hodgkinson Province imply that these parts are characterised by different crustal sources and crustal evolution histories.