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A-type granites are widespread in most orogenic belts, and their petrogenesis has played an important role in reconstructing orogenic events. However, their sources, even today, are a subject of considerable controversy. At least four models have been proposed for their formation, namely, melting of a previously melted source, fractionation of basaltic magma, anatexis of crustal igneous sources, and magma mixing. Here we present Early Jurassic A-type granites in southeast (SE) China as an example of a shallow (ca. 15-20-km depth), igneous, crust-derived A-type granite. We present detailed laser ablation ICP-MS zircon U-Pb dating and major- and trace-element and Sr-Nd isotopic data for these granites and assess their origin and relationship to the geodynamics of the late Mesozoic extensive magmatism in SE China. The associated granites include the Zhaibei, Keshubei, Zhulanbu, and Guangze plutons, which were emplaced during the interval 191-188 Ma and occur in a northeast-trending belt, parallel to the present coastline. They consist mainly of syenogranite and alkali-feldspar granite, with minor monzogranite, in which biotite and amphibole are anhedral and interstitial to both feldspar and quartz. The granites have high SiO2 (71.3-78.4 wt%) and K2O + Na2O and low Al2O3 and CaO contents, with high (K2O + Na2O)/Al2O3 ratios. They are enriched in rare earth elements (except Eu) and depleted in Ba and Sr. They display 10,000Ga/Al > 2.6 and Zr + Nb + Ce + Y > 350 ppmand have high zircon saturation temperatures (up to 900°C). Their Sr-Nd isotopic compositions (initial 87Sr/86Sr ranges from 0.7070 to 0.7283 and #949;Nd(T) ranges from 0.1 to -10.2) are variable but consistent with those of the early Paleozoic granitoids in SE China. Geochemical data suggest that the Early Jurassic A-type granites were derived by dehydration melting of early Paleozoic hornblende- and biotite-bearing granitoids in the middle crust (ca. 15-20 km), induced by intraplating of mantle-derived basaltic magmas. We further suggest that they formed in an extensional tectonic regime caused by slab break-off of the Paleo-Pacific Plate. [ABSTRACT FROM AUTHOR]

The tectonic setting of the late mesozoic of South China is in a debate between two schools of thought: an intra-continental rift zone along a passive continental margin or active rifting associated with subduction of the paleo-Pacific Plate. In this study, we present new sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages, along with geochemical data of three basic dikes that cross-cut the Dexing porphyry copper deposit. The deposit is the largest of its kind in eastern China and part of large scale mineralization associated with Mesozoic magmatic activity in the area. Our results indicate that the dikes were emplaced in the Late Jurassic with an average U-Pb age of 153.5 ± 2.4 Ma. The intrusions have bulk εNd(t) of ca +0.7 and zircon εHf(t) value of +1.54 to +6.92. Based on relatively enriched light rare earth elements (LREE) and depleted high-field-strength elements (HFSE) abundances with pronounced negative Ta-Nb, Hf-Zr and Ti anomalies in multi-element diagrams, we propose that these dikes were derived from a subduction-modified lithospheric mantle source. The variability in Hf isotopes identifies some degree of crustal contaminations. Our data support a scenario with a back-arc extensional setting or an intra-arc rift environment associated with the westward subduction of the paleo-Pacific Plate at or prior to the late Jurassic as the most likely cause for these subduction signatures. [ABSTRACT FROM AUTHOR]

This paper presents the first detailed zircon U–Pb chronology, major and trace element, and Nd–Hf isotope geochemistry of two Neoproterozoic plutons (Shanhou and Jiangshan) along the northwest side of the Jiangshan–Shaoxing suture, Zhejiang province, South China. The Shanhou pluton consists of gabbros, dioritic rocks and monzogranites. SHRIMP and LA-ICP-MS zircon U–Pb dating indicates that the gabbros (∼846 Ma), dioritic rocks (∼845 Ma) and monzogranites (∼847 Ma) were emplaced simultaneously. The Jiangshan pluton consists mainly of dioritic rocks that were also emplaced in the middle Neoproterozoic with a SHRIMP zircon U–Pb age of ca. 842 Ma. The Shanhou gabbros are mainly high-K calc-alkaline, and are enriched in LREE and LILE and depleted in HFSE with marked negative Ta–Nb anomalies. They have positive ɛ Nd (T) (2.0–3.5) and ɛ Hf (T) ( in-situ zircon) (3.3). The Shanhou and Jiangshan dioritic rocks as well as the Shanhou granites are also high-K calc-alkaline, enriched in LREE and LILE and depleted in HFSE with marked negative Ta–Nb anomalies. They also show positive ɛ Nd (T) (0.1–4.7) and ɛ Hf (T) ( in-situ zircon) (0.8–5.0). Detailed elemental and isotopic data suggest that both plutons were formed in a continental arc setting with gabbros derived from partial melting of subduction-modified mantle wedge. Such gabbroic magmas underwent fractionation crystallization of clinopyroxene + amphibole, forming the less felsic dioritic rocks. Progressive fractionation crystallization of amphibole + plagioclase from the evolved melts with a little crustal assimilation produced the more felsic dioritic rocks and granites. Our new data suggest that final amalgamation between the Yangtze and Cathaysia blocks postdated 842 Ma. [ABSTRACT FROM AUTHOR]

Abstract: Mesozoic lamprophyres are widely present in gold province in the Jiaodong Peninsula. In this study, we analyzed major and trace elements and Sr–Nd–Pb isotopic compositions of lamprophyres from the Linglong and Penglai Au-ore districts in the Jiaodong Peninsula, in an attempt to better understand Mesozoic lithospheric evolution beneath the eastern North China Craton. These lamprophyre dikes are calc-alkaline in nature, and are characterized by low concentrations of SiO2, TiO2 and total Fe2O3, high concentrations of MgO, Mg# and compatible element, enriched in LREE and LILE but variably depleted in HFSE. They display initial 87Sr/86Sr ratios of 0.709134–0.710314, εNd(t) values of −13.2 to −18.3, 206Pb/204Pb of 17.364–17.645, 207Pb/204Pb of 15.513–15.571 and 208Pb/204Pb of 37.995–38.374. Interpretation of elemental and isotopic data suggests that the Linglong and Penglai lamprophyres were derived from partial melting of a phlogopite- and/or amphibole-bearing lherzolite in the spinel–garnet transition zone. The parental magma might have experienced fractionation of olivine and clinopyroxene, and minor crustal materials were incorporated during ascent of these mafic magmas. Before ~120Ma of emplacement of these calc-alkaline lamprophyres, the ancient lithospheric mantle was variably metasomatized by hydrous fluids rather than melts from subducted/foundered continental crust. It is proposed that continuous modification by slab-derived hydrous fluids from the Paleo-Pacific plate converted the old cratonic lithospheric mantle to Mesozoic enriched lithospheric mantle. Geodynamic force for generation of these lamprophyres may be related to large scale lithospheric thinning coupled with upwelling of the asthenosphere beneath the North China Craton. Continental arc-rifting related to the Paleo-Pacific plate subduction is favored as a geodynamic force for the cratonic lithosphere detachment. [Copyright &y& Elsevier]

The western Kunlun orogen occupies a key position along the tectonic junction between the Pan-Asian and Tethyan domains, reflecting Proto- and Palaeo-Tethys subduction and terrane collision during early Palaeozoic to early Mesozoic time. We present the first detailed zircon U–Pb chronology, major and trace element, and Sr–Nd–O–Hf isotope geochemistry of the Qiukesu pluton and its microgranular enclaves from this multiple orogenic belt. SHRIMP zircon U–Pb dating shows that the Qiukesu pluton was emplaced in the early Silurian (ca. 435 Ma). It consists of weakly peraluminous high-K calc-alkaline monzogranite and syenogranite, with initial87Sr/86Sr ratios of 0.7131–0.7229, ϵNd(T) of –4.1 to –5.7, δ18O of 8.0–10.8‰, and ϵHf(T) (in situzircon) of –4.9. Elemental and isotopic data suggest that the granites formed by partial melting of lower-crustal granulitized metasedimentary-igneous Precambrian basement triggered by underplating of coeval mantle-derived enclave-forming intermediate magmas. Fractional crystallization of these purely crustal melts may explain the more felsic end-member granitic rocks, whereas such crustal melts plus additional input from coeval enclave-forming intermediate magma could account for the less felsic granites. The enclaves are intermediate (SiO257.6–62.2 wt.%) with high K2O (1.8–3.6 wt.%). They have initial87Sr/86Sr ratios of 0.7132–0.7226, ϵNd(T) of –5.0 to –6.0, δ18O of 6.9–9.9‰, and ϵHf(T) (in situzircon) of –8.1. We interpret the enclave magmas as having been derived by partial melting of subduction-modified mantle in the P–T transition zone between the spinel and spinel-garnet stability fields. Our new data suggest that subduction of the Proto-Tethyan oceanic crust was continuous to the early Silurian (ca. 435 Ma); the final closure of the Proto-Tethys occurred in the middle Silurian. [ABSTRACT FROM AUTHOR]

Abstract: The Central Tianshan zone is located between the Turpan–Hami and Tarim blocks and played a pivotal role in crustal evolution and collisional tectonics of the southern Altaids (or the Central Asian orogenic belt). The Xingxingxia granodiorite in the eastern Central Tianshan is an Early Paleozoic (424.9±5.8Ma) intrusion. Petrography, geochemistry and Sr–Nd–Hf isotopes suggest that the Xingxingxia granodiorite was genetically related to a volcanic arc, emplaced above a subduction zone. Thus, the Central Tianshan zone was a magmatic arc above an early Paleozoic subduction zone of the Paleoasian ocean. We present LA-ICP-MS zircon U–Pb dating and Hf isotope determinations of Precambrian zircon grains trapped in the Xingxingxia granodiorite. Three populations of inherited zircons indicate that Neoproterozoic (809±41Ma; ε Hf(t)=0.10–5.73), Mesoproterozoic (~1400Ma; ε Hf(t) 8.71–10.05) and Paleoproterozoic (~1750Ma; ε Hf(t) 0.11 and 4.80) tectonomagmatic events in the Central Tianshan zone, which are comparable with those in the Tarim block. Combined with a series of similar geological characteristics between these two blocks, it is suggested that the Central Tianshan zone might have been originally a part of the Tarim block, and was separated from it during the Early Paleozoic time due to pull-apart caused by southward subduction of the Northern Tianshan ocean, a branch of the Paleoasian ocean. [Copyright &y& Elsevier]

Abstract: The Qinling–Dabie–Sulu orogen marks the junction between the North and South China Blocks. However, the exact timing of the final coalescence of the North and South China Blocks in the Qinling orogen is poorly constrained. This paper presents new SHRIMP zircon U–Pb chronology, major and trace elements, and Sr–Nd–Hf isotope data for five early Mesozoic granitic plutons across the Qinling orogen. SHRIMP zircon U–Pb dating shows that four plutons were emplaced in the Carnian (227–218Ma) of Late Triassic with a southward-younging trend and one pluton was emplaced in the Norian (∼211Ma) of Late Triassic. The Carnian plutons consist of high-K calc-alkaline granitoids (quartz monzodiorite, quartz monzonite, granodiorite and monzogranite) and calc-alkaline diorite. These rocks are mainly metaluminous and are characterized by high Sr and low Y and Yb contents, with high Sr/Y and La/Yb ratios, and by high Mg#, higher than pure crustal melts. The Norian pluton is composed of high-K calc-alkaline two-mica granites, which are peraluminous. These granites have low Sr and high Y and Yb contents and show similar Mg# to pure crustal melts. Detailed elemental and isotopic data suggest that the Carnian plutons were emplaced in a continental arc setting coupled with the northward subduction of the Paleo-Tethyan oceanic crust. Partial melting of subducted sediments triggered by dehydration of the underlying igneous oceanic crust, with subsequent melts interacting with the overlying mantle wedge, formed the high-K calc-alkaline granitic magmas. Partial melting of the hybridized peridotitic mantle wedge induced by slab melts generated the calc-alkaline dioritic magma. The Norian pluton was emplaced during continental collision between the South Qinling terrane and South China Block, which marks the final integration of the North and South China Blocks. Partial melting of subducted sediments at a shallow depth (<30km) in the collision (overthrust) zone could account for the origin of the Norian peraluminous granites. Our new data suggest that the final coalescence of the North and South China Blocks in the Qinling orogen is not synchronous with that in the Dabie–Sulu orogen, and thus, the Paleo-Tethyan oceanic basin between the North and South China Blocks most likely occurred as a ‘scissors-like’ shape, with closure in the Anisian (∼240Ma) of Middle Triassic in the eastern part (Dabie–Sulu) and in the Norian (∼211Ma) of Late Triassic in the western part (Qinling). [Copyright &y& Elsevier]

Abstract: This paper presents detailed SHRIMP zircon U–Pb chronology, major and trace element, and Sr–Nd–Hf isotope geochemistry of three intrusive plagiogranite bodies formed in an island arc setting within the Oytag ophiolite suite of the Oytag–Kuda Suture Zone. SHRIMP zircon U–Pb dating of two of these intrusions shows that they were emplaced into the Oytag volcanic rocks at 337.5±4.1 Ma and 327.7±4.9 Ma, and that the younger intrusion contains inherited zircons ranging from 435.3 to 480.8 Ma. Both intrusions are composed of low-Al trondhjemite and tonalite. The rocks have low K2O and Sr and high Y contents with low Sr/Y ratios. They have relatively low rare earth element (REE) concentrations and are depleted in light REE (LREE) and relatively enriched in heavy REE (HREE), with marked negative Eu anomalies in the chondrite-normalized REE patterns. They have initial 87Sr/86Sr ratios of 0.7048 to 0.7068 and ε Nd (T) values of 6.2 to 7.6, which are lower than those of typical MORB. In situ Hf isotopic compositions of zircons with Early Carboniferous age from both intrusions are characterized by positive initial ε Hf values, ranging from +12.5 to +19.5, similar to typical MORB. The inherited Ordovician zircons in the younger intrusion have initial ε Hf values of −1.9 to +3.1, similar to zircons from Ordovician granitoids in the region. Detailed elemental and isotopic data suggest that the Oytag plagiogranites were formed in an oceanic island arc setting, by differentiation of arc tholeiitic magmas that formed in response to the intra-oceanic subduction. The inherited zircons are interpreted as the xenocrysts captured from the incipient oceanic crust that contains relicts of discrete fragments of continental crust with Ordovician zircons, through which the plagiogranite was emplaced. The Oytag ophiolite suite might be the remnants of an ancient island arc, the basement of which was the incipient oceanic crust. The Oytag–Kuda Suture Zone is suggested to be a multiple suture zone that represents the remnants of both the Proto-Tethyan and Paleo-Tethyan oceans. The western Kunlun orogen was therefore not a long-lived active continental margin during the early and late Paleozoic times. It most likely underwent at least two orogenic cycles and thus might represent a multiple orogenic belt. [Copyright &y& Elsevier]

Abstract: SHRIMP zircon U–Pb dating, mineral chemical, element geochemical and Sr–Nd–Pb–Hf isotopic data have been determined for the Yulong monzogranite-porphyry in the eastern Tibet, China. The Yulong porphyry was emplaced into Triassic strata at about 39 Ma. The rocks are weakly peraluminous and show shoshonitic affinity, i.e., alkalis-rich, high K2O contents with high K2O/Na2O ratios, enrichment in LREE and LILE. They also show some affinities with the adakite, e.g., high SiO2 and Al2O3, and low MgO contents, depleted in Y and Yb, and enrichment in Sr with high Sr/Y and La/Yb ratios, and no Eu anomalies. The Yulong porphyry has radiogenic 87Sr/ 86Sr (0.7063–0.7070) and unradiogenic 143Nd/ 144Nd (ε Nd =−2.0 to −3.0) ratios. The Pb isotopic compositions of feldspar phenocrysts separated from the Yulong porphyry show a narrow range of 206Pb/ 204Pb ratios (18.71–18.82) and unusually radiogenic 207Pb/ 204Pb (15.65–15.67) and 208Pb/ 204Pb (38.87–39.00) ratios. In situ Hf isotopic composition of zircons that have been SHRIMP U–Pb dated is characterized by clearly positive initial ε Hf values, ranging from +3.1 to +5.9, most between +4 and +5. Phenocryst clinopyroxene geothermometry of the Yulong porphyry indicates that the primary magmas had anomalously high temperature (>1200 °C). The source depth for the Yulong porphyry is at least 100 km inferred by the metasomatic volatile phase (phlogopite–carbonate) relations. Detailed geochemical and Sr–Nd–Pb–Hf isotopic compositions not only rule out fractional crystallization or assimilation-fractional crystallization processes, but also deny the possibility of partial melting of subducted oceanic crust or basaltic lower crust. Instead, low degree (1–5%) partial melting of a metasomatized lithosphere (phlogopite–garnet clinopyroxenite) is compatible with the data. This example gives a case study that granite can be derived directly by partial melting of an enriched lithospheric mantle, which is important to understand the source and origin of diverse granites. [Copyright &y& Elsevier]

A series of granitoids from Proterozoic to Cenozoic age occurred in the western Kunlun orogenic belt, Xinjiang, northwestern China. Several intrusions such as the West Datong (Middle Caledonian age), North Kuda (Late Caledonian age) and Kuzigan, Karibasheng, Zankan (Himalayan age) plutons have shoshonitic affinity. Their rock assemblages include (quartz) monzodiorite–(quartz) monzonite–quartz syenite (Middle Caledonian) or monzonitic granite–granite (Late Caledonian) or biotite (monzonitic) granite–diopside granite–diopside syenite (Himalayan). Generally, biotite is iron–phlogopite, with some eastonite and high Mg/(Mg+FeT) and Fe3+/Fe2+ ratio. Amphibole is mainly edenitic hornblende and magnesian hastingsitic hornblende, with some edenite and higher Mg/(Mg+FeT) and Fe3+/Fe2+ ratio. The rocks show SiO2 contents of 52.77–71.85% and high K2O+Na2O (mostly >8%, average 9.14%), K2O/Na2O (mostly >1, average 1.50) and Fe2O3/FeO (0.85–1.51, average 1.01) and low TiO2 contents (0.15–1.12%, average 0.57%). Al2O3 contents (13.01–19.20%) are high but variable. The granitoids are prominently enriched in LILE, LREE and volatiles such as F. However, the studied shoshonitic granitoids among the three intrusive periods also show differences in isotopic compositions and trace element concentrations, suggesting their different geneses: the origin of the West Datong pluton is probably related to the involvement of subducted oceanic crust sediments into the mantle source; the North Kuda and Himalayan plutons could have been generated by partial melting of subducted oceanic crust sediments or metasediments of thickened continental lower crust in the process of late-orogenic slab break-off or lithospheric thinning. [Copyright &y& Elsevier]

• We have identified hydrothermal zircons from the Xiadian gold deposit, Jiaodong. • They show homogeneous low CL-response image and have high U with low Th/U. • Direct LA-ICP-MS U-Pb dating shows the Paleocene gold mineralization. • In-situ Hf isotopes suggest lithospheric mantle-derived ore-forming fluids. The eastern North China Craton is characteristic of Mesozoic cratonic destruction and largescale gold mineralization. Previous geochronological studies by 40Ar–39Ar dating on alteration minerals such as sericite and K-feldspar and Rb–Sr and 40Ar–39Ar dating on quartz and pyrite suggested that the gold mineralization occurred in Early Cretaceous. We have identified hydrothermal zircons from the orebody and alterated rocks in the Xiadian gold deposit, Jiaodong Peninsula. These zircons contain two phase (vapor-liquid) fluid inclusions or enclose hydrothermal alteration minerals such as sericite. They show homogeneous low CL-response image and have high U with low Th/U, and also show enriched and flatter normalized LREE pattern with high La and low (Sm/La) N and Ce/Ce* relative to magmatic zircons. Their petrographical, textural and compositional features strongly suggest that they mainly crystallized from the hydrothermal fluids during the pyrite–sericite–quartz alteration that was closely related to the gold mineralization. Direct LA-ICP-MS U-Pb dating on such hydrothermal zircons indicates that the gold mineralization in the Xiadian deposit mainly occurred during the Paleocene and underwent a prolonged metallogenic process (68.7–56.7 Ma), most likely commenced at the end of Cretaceous and lasted at the end of Paleocene. In-situ Hf isotopic compositions of the hydrothermal and inherited zircons suggest that the ore-forming fluids might have been derived from an enriched lithospheric mantle, followed by interacting with Archean metamorphic basement during ascent. Such a gold mineralization event might have been associated with the early Cenozoic uppermost lithospheric thinning in eastern North China Craton. It has important implications for further understanding the geneses and the geodynamics of gold deposits in the whole eastern North China Craton. [ABSTRACT FROM AUTHOR]

Abstract: The Linglong granite is one of the most important Mesozoic plutons in the Shandong Peninsula, eastern China, and its petrogenesis has long been controversial, particularly with regard to the nature of source region and geodynamic setting. Our new precise zircon U–Pb dating results reveal that the Linglong granite was emplaced in the Late Jurassic (157–160Ma). In addition, abundant inherited zircons are identified in the granite with four groups of age peaked at ~208, ~750, ~1800 and ~2450Ma. Geochemical studies indicate that the Linglong granite is weakly peraluminous I–type granite, and is characterized by high SiO2, Sr and La, but low MgO, Y and Yb contents, strongly fractionated REE pattern and high Sr/Y and La/Yb ratios. It also exhibits high initial 87Sr/86Sr ratios (0.7097 to 0.7125), low εNd(t) (−17.7 to −20.3) and variable zircon εHf(t) (−22.2 to −8.7) values. Calculation of the zircon saturation temperature (TZr) reveals that the magma temperatures are 760±20°C, and the lowest TZr value of 740°C may be close to initial magma temperature of this inheritance-rich rock. Interpretation of the elemental and isotopic data suggests that the Linglong granite has some affinities with the adakite, and was most likely derived from partial melting of thickened lower crust without any significant contribution of mantle components. The presence of a large number of inherited zircons and variable Sr–Nd–Hf isotopic compositions reveal that the Linglong granite probably has multiple sources consisting of the lower crust of both South China Block and North China Block, as well as the collision-related alkaline rocks and UHP metamorphic rocks. The continental arc-rifting related to the Izanagi plate subduction was the most likely geodynamic force for formation of the Jurassic Linglong adakatic granite in the Shandong Peninsula. [Copyright &y& Elsevier]

Abstract: The widespread occurrence of Mesozoic granites in the Gan-Hang Belt in Southeast China is associated with similarly widespread, economically important mineralization, but the precise timing, origin, and plate tectonic significance of these granites are not well understood. We have studied two of these (Early Cretaceous) granite bodies, the Yangmeiwan granite and the Daqiaowu granitic porphyry, from the northeastern part of the Gan-Hang Belt in western Zhejiang Province by zircon U-Pb geochronology, major and trace element analyses, and Nd–Hf isotopic analyses. LA-ICP-MS and SHRIMP U–Pb dating of zircon grains from these two granites yield ages of 133–136Ma, representing a Early Cretaceous magmatic event. These granitic rocks are metaluminous to weakly peraluminous and have a pronounced A-type geochemical signature with high Na2O+K2O, Fe2O3*/MgO and Ga/Al ratios. They show low CaO, MgO and TiO2 contents, enrichment in some LILEs (such as Rb and Th) and HFSEs (such as Zr, Y), depletion in Sr, Ba, P, Eu and Ti. They also show A2 subtype affinity and were probably formed at a high temperature (~810°C for Yangmeiwan granite and ~850°C for Daqiaowu granitic porphyry). These A-type granitic rocks show bulk rock εNd(t) values in the range of −6.5 to −3.6 and zircon εHf(t) values from −7.8 to −0.9, with Mesoproterozoic TDM c ages for both Nd and Hf isotopes. Geochemical and isotopic data suggest that these A-type granitic rocks were generated largely by partial melting of granulitized Mesoproterozoic metamorphic basement rocks (including parametamorphic and orthometamorphic rocks), with a possible input of mantle-derived materials and followed by subsequent fractional crystallization. Our new data together with previous published data suggest that the Cretaceous A-type granitic rocks with ages between 137Ma and 122Ma occurred along the Gan-Hang Belt, indicating an important Mesozoic extensional event in Southeast China. This event represents either a back-arc extension or an intra-arc rift due to the roll-back of the paleo-Pacific plate, and it started as early as ~137Ma in Xiangshan and Xinlu basins. It is earlier than ~130Ma as previously suggested in the studied region and later than that along the south part of the Shi-Hang Zone. With ongoing extension during slab roll-back of paleo-Pacific plate, the crust and lithospheric mantle became progressively thinned. The upwelling of asthenosphere would have triggered crustal rocks to partially melt, generating granitic magmas. Our new geochemical data also suggest that mantle-crust interaction in the formation of the A-type granitic magma along the Gan-Hang Belt gradually intensified from early to late stages between ca. 137 and ca. 122Ma. [Copyright &y& Elsevier]

• Zircon U–Pb ages reveal wall rocks of the Kanggur deposit formed at ca. 340 Ma. • The wall rocks of the Kanggur deposit were formed in an oceanic arc setting. • The ore-forming materials of the Kanggur deposit were predominantly derived from andesite of the wall rocks. The Kanggur gold polymetallic deposit, located in the western segment of the Kanggur–Huangshan Shear Zone (KHSZ) of the Chinese North Tianshan, is the largest shear zone-controlled gold polymetallic deposit in this region. The gold mineralization is hosted by Early Carboniferous volcanic rocks of the Yamansu Formation, which is predominantly composed of andesite, dacite, and tuff. In this contribution, we present U–Pb age data and Hf isotopes of zircon from wall rocks associated with mineralization in the Kanggur deposit, as well as whole-rock geochemistry of the wall rocks with the goal of characterizing the petrogenesis of the deposit, and the sources of the ore-forming materials. Our new LA–ICP–MS zircon age data indicate that the wall rocks formed at ca. 340 Ma in the Early Carboniferous (andesite at 338.0 ± 1.7 Ma, dacite at 338.1 ± 2.2 Ma, rhyolite 332.4 ± 2.8 Ma, and granite porphyry at 342.6 ± 1.9 Ma). These wall rocks are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs; e.g., U, K, and Pb), and depleted in high field strength elements (HFSEs; e.g., Nb, Ta, and Ti). Based on the lack of ancient crustal basement rocks in the Qoltag Arc, the lithological assemblage of andesite–dacite–rhyolite, the presence of chert, and the enrichment of andesite and dacite in Na 2 O (3.35–6.89 wt%) relative to K 2 O (0.67–2.42 wt%), it is inferred that the Early Carboniferous volcanic wall rocks of the deposit formed in an oceanic arc setting. Considering the similar isotopic compositions of andesite, dacite, rhyolite, and granite porphyry (εNd (t) = −0.12 to 0.64 and εHf (t) = 6.05 to 8.96 for andesite, εNd (t) = 1.01 to 3.02 for dacite; εNd (t) = 4.20 to 4.91 and εHf (t) = 11.02 to 13.79 for rhyolite, and εNd (t) = 1.65 to 2.13 and εHf (t) = 4.70 to 6.80 for granite porphyry) and juvenile Hf model ages (T DM1 = 610 to 730 Ma for andesite, T DM2 = 460 to 640 Ma for rhyolite, and T DM2 = 910 to 1050 for granite porphyry), it is suggested that the primary magma from which the andesite and dacite crystallized was derived from partial melting of metasomatized mantle wedge, whereas, the magma from which the rhyolite and granite porphyry crystallized was derived from partial melting of juvenile lower crust. The bulk S isotope composition (δ34S V-CDT) of these wall rocks varies from −0.8 to 8.7‰ (average of 4.8‰), with the S isotope composition of the andesite and rhyolite being similar to that of pyrite in mineralized rock. The bulk Pb isotope composition of these wall rocks ranges from 17.561 to 18.258 206Pb/204Pb, 15.535 to 15.602 207Pb/204Pb, and 37.593 to 38.118 208Pb/204Pb, with the Pb isotope composition of andesite being similar to that of pyrite from gold-bearing ores in the Kanggur deposit. The high abundance of sulfides in the wall rocks, and the similar S–Pb isotope compositions of ores and andesite suggests that the ore-forming materials were likely derived from the andesite wall rocks. [ABSTRACT FROM AUTHOR]