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The East Kunlun Orogenic Belt (E‐KOB) of the northern Tibetan Plateau is an accretionary orogenic belt, which has experienced complicated tectonic evolutionary processes of the Proto‐ to Palaeo‐Tethys Ocean. The Muztagh‐Buqingshan‐Anemaqen ophiolitic mélange zone (MBAM) is an accretionary complex related to the northward subduction of the Tethyan Ocean. Numerous intrusions outcropped in MBAM have witnessed the long‐term subduction‐accretionary process and thus site the key to comprehending the tectonic evolution of the E‐KOB, as well as the Tethyan Ocean. In this study, petrological, geochronological, and geochemical studies of the Marzheng diorites in the MBAM were carried out to explore the Early Palaeozoic tectonic evolution of the E‐KOB. Zircon U–Pb dating analysis suggests that the diorites were formed in the Early Ordovician at ca. 470 Ma. Furthermore, the εHf(t) values (5.3–14.1), Mg# values (39.7–51.2), and Nb/Ta (12.8–14.8), Zr/Hf (33.8–44.8), and Lu/Yb (0.15–0.16) ratios are generally close to those of depleted mantle‐derived rocks and the diorites were originated from a depleted asthenosphere mantle source. In addition, these diorites are characterized by enriched light rare earth elements (LREEs) (La and Nd) and depleted high‐field‐strength elements (HFSEs) (Nb, Ta, P, and Ti), similar to the fingerprints of arc‐related gabbroic‐dioritic rocks. This is also consistent with their high H2Omelt (6.0–8.3%) and oxygen fugacity (logfO2 = −14.3 to −13.5) features, indicating that they were formed in a subduction‐related setting. Our new investigations suggest that the Proto‐Tethys Ocean in the East Kunlun was still actively subducting northward during the Early Ordovician. [ABSTRACT FROM AUTHOR]

The Permian mafic dykes of Santanghu Basin offer an opportunity to study the nature of mantle source and tectonic setting of the basin, as well as to provide the theoretical basis for structural transformation of East Junggar region. In this study, zircon U–Pb geochronology, mineral composition analysis, whole‐rock elemental, and Sr‐Nd isotopic geochemistry were conducted to explore the origin and evolution of the primitive magma. LA‐ICPMS zircon U–Pb dating yields ages at 269 Ma. The elemental geochemistry results suggest enrichments in Ba, Pb, and Sr but depletions in Nb, Ta, Zr, and Hf, which indicate that the magma source was influenced by fluid metasomatism. All samples show moderate initial Sr‐Nd isotope results ((87Sr/86Sr)I = 0.704299 to 0.704490 and εNd(t) = +6.16 to +6.83) and have high Sm/Yb ratios, which suggest that the diabases were derived from partial melting of 5%–7% spinel‐garnet Iherzolite lithospheric mantle. Combined with petrological, geochronological data, and the regional tectonic background, it is interpreted that the diabases from Santanghu Basin originated from lithospheric mantle metasomatized by subduction fluids under the background of intracontinental extension. [ABSTRACT FROM AUTHOR]

Early Jurassic Kaoshan medium‐ and fine‐grained syenogranites emplaced along the Yitong–Shulan Fault Zone in the southern part the Zhangguangcai Range, central Jilin Province, intruded Middle Triassic granitoids and Carboniferous‐Devonian intrusive rocks. They have medium‐ and fine‐grained textures and contain K‐feldspar, quartz, plagioclase, and biotite. They are peraluminous (A/CNK = 1.13–1.20) and have high values of SiO2 (74.60–75.82 wt%), total alkalis (Na2O + K2O = 8.28–9.18 wt%), light rare earth elements (20.89–56.14 ppm), large‐ion lithophile elements, and FeO/MgO = 2.78–5.93. In contrast, they feature low values of CaO (0.40–0.49 wt%), TiO2 (0.05–0.14 wt%), P2O5 (0.02–0.04 wt%), Sr (24.20–62.59 ppm), heavy rare earth elements (5.14–11.80 ppm), high‐field‐strength elements, and δEu (0.41–0.76), and the calculated zircon saturation temperatures (Tzr) range from 804 to 870°C, all of which are similar to the geochemical signatures of anorogenic A1‐type granites. Zircon U–Pb geochronology analyses from the medium‐ and fine‐grained syenogranites yield concordia ages of 193.18 ± 0.95 Ma (MSWD = 6.7, n = 18) and 190.29 ± 0.92 Ma (MSWD = 8.7, n = 17), respectively, and belong to the Early Jurassic Sinemurian stage. In situ Hf isotope analyses of dated zircons yield εHf(t) values ranging from +17.0 to +9.7 and Hf model ages (TDMC) of 225–614 Ma. Their whole‐rock (87Sr/86Sr)i (0.704740–0.704133) and εNd(t) values (+2.8 to +0.2) are similar to those of many coeval A2‐type granites in this region, and they form an A‐type granite assemblage. Consequently, the Kaoshan medium‐ and fine‐grained syenogranites were probably derived from partial melting of juvenile lower crust and might be related to the subduction of the Palaeo‐Pacific Plate. [ABSTRACT FROM AUTHOR]

The southern Jiangxi Province is an important part of the fluorite mineralization belt in South China. Fluorite ore bodies are primarily in the contact zone between the Devonian Huitong granitic complex and the Late Cretaceous Ganzhou Formation, controlled by the NE‐trending faults. Zircon U–Pb dating of the Huitong granitic complex yields emplacement ages of 410.7 ± 1.4 Ma and 400.7 ± 4.6 Ma, while the Sm–Nd dating of the fluorite yields an isochron age of 94 ± 2 Ma, suggesting that the Huitong granitic complex is the host rock. Fluid inclusions in the fluorite show low homogenization temperatures (136–207°C), salinities (1.23–3.87 wt% NaCl), and densities (0.87–0.95 g/cm3), suggesting that the ore‐forming fluid is an NaCl‐H2O system of low temperature, salinity, and density. Raman spectroscopy showed that the fluid phase is dominated by water. The δDVSMOW values of the fluid inclusions in the Tongda fluorite ranged between −59.5 and −55.2‰, while the δ18OVSMOW values of the fluorite ranged from −7.2 to −5.6‰. Collectively, the ore‐forming fluid is dominated by meteoric water, possibly with a minor contribution of hydrothermal fluid. Both the interaction with host rocks and the cooling of hydrothermal fluids are the likely mechanisms of underlaying fluorite precipitation at low temperatures. The mineralization occurred in extensional faults during the Late Cretaceous related to the subduction of the Palaeo‐Pacific Oceanic Plate. [ABSTRACT FROM AUTHOR]

Pusangguo is a high‐grade skarn‐type Cu‐dominated polymetallic deposit and the only large‐sized Cu‐Pb‐Zn‐(Co‐Ni) deposit in the Gangdese metallogenic belt (GMB); the magmatic rocks associated with this deposit are poorly documented, and their petrogenesis and geodynamic setting are unclear. To explore these issues, we present zircon U–Pb ages along with Hf isotopic, whole‐rock geochemical, and Sr–Nd–Pb isotopic data for Pusangguo biotite granodiorite (PBG) and Pusangguo diorite porphyrite (PDP) in this deposit. Zircon U–Pb dating for these rocks indicates that they were emplaced during the Miocene (13.6–14.6 Ma). Geochemically, both PBG and PDP show characteristics of adakites, with intermediate SiO2 (65.55–67.30 wt% and 60.56–58.27 wt%, respectively), relatively high Al2O3 (15.28–15.85 wt% and 17.71–16.71 wt%, respectively) and Sr (599–723 ppm and 687–1,616 ppm, respectively) and low Y and Yb. In addition, they show relatively low ratios of (87Sr/86Sr)i and (206Pb/204Pb)i, (207Pb/204Pb)i and (208Pb/204Pb)i and relatively low values of εNd(t) and εHf(t). The Sr‐Nd‐Pb‐Hf isotopes of PBG and PDP are similar to those of the Miocene adakitic rocks associated with the porphyry–skarn deposits in the GMB, indicating that they were predominantly generated by partial melting of the thickened juvenile Lhasa Terrane lower crust and the PDP were likely to be generated through mixing between the magma parental to the PBG and a mafic end‐member. By combining our results with the previously reported results, we suggest that the model of delamination of the overthickened mantle lithosphere of Lhasa Terrane and convective upwelling of mantle asthenosphere which may involve Indian continental lithosphere. [ABSTRACT FROM AUTHOR]

The ages and source of Late Cretaceous mafic dolerite dykes of the Songliao Basin were determined using geochronological, geochemical, zircon Hf, whole‐rock Sr–Nd isotopic, and zircon fission tract. The results show that (a) petrographic data reveal doleritic, poikiloblastic textures, and amygdale structures of the dolerite dykes. (b) LA‐MC‐ICP‐MS U–Pb analysis of zircons yielded an age of 70.0 ± 3.0 Ma of one of these mafic dykes in agreement with the zircon fission track age (69–68 Ma) of host rocks within uncertainty, placing them within the Late Cretaceous. (c) Geochemical researches indicate that the dykes are classified as the alkaline and tholeiitic series according to their major elements and characterized by high Na2O (2.79–4.89 wt.%), TiO2 (1.63–2.71 wt.%), and low K2O (0.46–2.45 wt.%). And they have enrichment of incompatible elements (e.g., K, Ti, Rb, Ba, Th, U, Nb, Ta, and REEs), high Rb/Sr (0.026–0.066), LaN/YbN (3.83–15.93), near‐chondritic HREEs ([Gd/Yb]N = 1.78–3.37), low Sm/Nd (0.202–0.282) ratios, and with negligible Eu anomalies (Eu/Eu* = 0.98–1.06). The dykes contain relatively low amounts of radiogenic Sr, as shown by (87Sr/86Sr)i values (0.7037–0.7045), and have positive values of εNd(t) (3.66–5.40) and εHf (t) (2.66–7.45), suggesting that the mafic dykes have been derived from partial melting of the depleted lithospheric mantle and contaminated by crust in the source region and formed in back‐arc rift settings caused by the subduction of the Pacific Oceanic Plate. All the above indicate large‐scale extensional event in Songliao Basin NE China at about 70 Ma. [ABSTRACT FROM AUTHOR]

This study presents zircon U–Pb ages and geochemical and Sr–Nd isotopic data for acid granites from the Uliastai continental margin, which is located in the Ulaan Tolgoi area of the south‐eastern Central Asian Orogenic Belt (CAOB). Although most samples have similar calc‐alkaline (K2O/Na2O = 0.55–1.70, average of 1.35) and peraluminous (A/CNK = 1.02–1.20 and A/NK = 1.09–1.87) characteristics, the granodiorites, monzogranites, and alkali feldspar granites exhibit distinct light rare earth element (LREE)/heavy REE (HREE) anomalies, including negative Nb, P, Ti, Sr, and Ba anomalies and negative εNd(t) values. These characteristics indicate that this complex massif comprises lower Early Carboniferous subduction‐related calc‐alkaline granodiorites (348 ± 1 Ma); an upper Early Carboniferous syn‐collisional segment characterized by S‐type, high‐K, calc‐alkaline, and peraluminous monzonitic granites (334 ± 1 Ma); and Late Carboniferous post‐orogenic extensional A2‐type peraluminous alkali feldspar granites (317 ± 1 Ma). Previous studies performed on coeval volcanic rocks and Early Palaeozoic granites in the same area have demonstrated that the Early Carboniferous granodiorites have the same geochemical characteristics as volcanic arc granites (VAGs), thus indicating that the northward subduction of the Hegenshan Ocean may have continued through the Early Carboniferous. The monzogranite and alkali feldspar granites, in conjunction with the Late Carboniferous lagged arc volcanic rocks observed in this area, suggest a syn‐collisional to post‐collisional setting. The new data presented in this study provide constraints on the timing of the transition from island‐arc magmatism to post‐collisional extension‐related magmatism in this region during the later stage of the Early Carboniferous. [ABSTRACT FROM AUTHOR]

We undertook zircon U-Pb dating and geochemical analyses of the Weitingchagan (WT) pluton in the Dong Ujimqi area, Northeast China, with an aim of determining their ages, petrogenesis and sources, which are important for understanding the Late Palaeozoic tectonic evolution of the Xing-Meng Orogenic Belt. The WT pluton consists of coarse- to medium-grained porphyritic granites in the core and medium- to fine-grained monzogranites in the rim, contains abundant microgranular enclaves and is intruded by small amounts of muscovite monzogranites. The results of LA-ICP-MS zircon U-Pb dating indicate that the WT composite pluton formed during the Late Carboniferous-Early Permian with the ages ranging from 289 Ma to 312 Ma. Petrological and geochemical characteristics of the WT pluton were derived from the partial melting of crustal materials, and the AFC process played an important role in the magmatic evolution. The porphyritic granites are I-type granite, and the monzogranites and muscovite monzogranites are highly fractionated I-type granite. Combined with previous studies on the contemporaneous magma-tectonic activities in the Uliastai Continental Margin, the study suggests that the WT pluton formed in an extensional environment, which may relate to the closure of the Palaeo-Asian Ocean. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Taolaituo porphyry-type molybdenum deposit is located in the eastern Inner Mongolia Autonomous Region in China. The mineralization occurs mainly as veins, lenses and layers within the host porphyry. To better understand the link between the mineralization and the host igneous rocks, we studied samples from the underground workings and report new SHRIMP II zircon U-Pb and Re-Os molybdenite ages, and geochemical data from both the molybdenites and the porphyry granites. Five molybdenite samples yield a Re-Os isochron weighted mean age of 133.0 ± 0.82 Ma, whereas the porphyry granitoids samples yield crystallization ages of 133 ± 1 Ma and 130.4 ± 1.3 Ma. The U-Pb and Re-Os ages are similar, suggesting that the mineralization is genetically related to the Early Cretaceous porphyry emplacement. Re contents of the molybdenites range from 21.74 to 42.45 ppm, with an average of 32.69 ppm, whereas δ34S values vary between 3.7‰ and 4.2‰, which is typical of mantle sulphur. The 206Pb/204Pb, 207Pb/ 204Pb and 208Pb/204Pb vary in the ranges of 18.276-18.385, 15.566-15.580 and 38.321-38.382, respectively. The Taolaituo Early Cretaceous granitoids are A-type granites. These observations indicate that the molybdenites and the porphyry granites were derived from a mixed source involving young accretionary materials and enriched subcontinental lithospheric mantle. A synthesis of geochronological and geological data reveals that porphyry emplacement and Mo mineralization in the Taolaituo deposit occurred contemporaneously with the Early Cretaceous tectonothermal events associated with lithospheric thinning, which was caused by delamination and subsequent upwelling of the asthenosphere associated with intra-continental extension in northeast China. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Yingchengzi gold deposit, located 10 km west of Shalan at the eastern margin of the Zhangguangcai Range, is the only high commercially valuable gold deposit in southern Heilongjiang Province, NE China. This study investigates the chronology and geodynamic mechanisms of igneous activity and metallogenesis within the Yingchengzi gold deposit. New zircon U-Pb data, fluid inclusion 40Ar/39Ar dating, whole-rock geochemistry and Sr-Nd isotopic analysis is presented for the Yingchengzi deposit to constrain its petrogenesis and mineralization. Zircon U-Pb dating of the granite and diabase-porphyrite rocks of the igneous complex yields mean ages of 471.7 ± 5.5 and 434 ± 15 Ma respectively. All samples are high-K calc-alkaline or shoshonite rocks, are enriched in light rare earth elements and large ion lithophile elements, and are depleted in high field strength elements, consistent with the geochemical characteristics of arc-type magmas. The Sr-Nd isotope characteristics indicate that the granite formed by partial melting of the lower crust, including interaction with slab-derived fluids from an underplated basaltic magma. The primary magma of the diabase-porphyrite was likely derived from the metasomatized mantle wedge by subducted slab-derived fluids. Both types of intrusive rocks were closely related to subduction of the ocean plate located between the Songnen-Zhangguangcai Range and Jiamusi massifs. However, fluid inclusion 40Ar/39Ar dating indicates that the Yingchengzi gold deposit formed at ~249 Ma, implying that the mineralization is unrelated to both the granite (~472 Ma) and diabase-porphyrite (~434 Ma) intrusions. Considering the tectonic evolution of the study area and adjacent regions, we propose that the Yingchengzi gold deposit was formed in a late Palaeozoic-Early Triassic continental collision regime following the closure of the Paleo-Asian Ocean. In addition, the Yingchengzi deposit could be classified as a typical orogenic-type gold deposit occuring in convergent plate margins in collisional orogens, and unlikely an intrusion-related gold deposit as reported by previous studies. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]