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This study reports zircon U–Pb geochronological, geochemical, and zircon Hf–O isotopic data for metavolcanic rocks from the Shitoukoumen and Yongji areas in central Jilin Province, northeast China, to reveal their petrogenesis and tectonic setting. The metavolcanic rocks collected from the Shitoukoumen and Yongji areas are composed of metabasaltic trachyandesite, metatrachyandesite, and metarhyolitic tuff. Zircon U–Pb dating results indicate that the metavolcanic rocks were erupted during 359–355 Ma. Metavolcanic rocks in the Shitoukoumen area can be divided into two groups according to their geochemical characteristics. Group‐I rocks (metabasaltic trachyandesite and metatrachyandesite) show geochemical features similar to those of ocean island basalt (OIB), with slightly lower zircon δ18O values (4.06 ± 0.42‰ to 5.16 ± 0.28‰) than those of mantle‐derived zircons, and depleted εHf(t) values (7.84–15.4). Group‐II rocks (metabasaltic andesite) show similar geochemical characteristics to those of normal mid‐ocean ridge basalt (N‐MORB). Group‐I rocks may have been derived from partial melting of enriched mantle involving high‐temperature altered oceanic crust, whereas Group‐II rocks originated mainly from partial melting of depleted mantle. Metarhyolitic tuffs from the Yongji area have high SiO2 and K2O contents, as well as high Ga/Al ratios, and show similar geochemical characteristics to those of A‐type rhyolites. The results of the study, together with published data, indicate that the eastern segment of the northern margin of the North China Craton was a passive continental margin setting during the early Carboniferous, and that the Paleo‐Asian Ocean remained open along the Changchun–Yanji suture belt until the early Carboniferous. [ABSTRACT FROM AUTHOR]

We present zircon U–Pb and Hf isotopic and whole‐rock geochemical data for late Paleozoic igneous rocks in the central Great Xing'an Range, northeast China, to constrain the late Paleozoic amalgamation history of the united Xing'an–Erguna and Songnen–Zhangguangcai Range massifs. Based on zircon U–Pb dating, we ascertain three main stages of magmatic events: Late Devonian (381–364 Ma), early Carboniferous (360–341 Ma), and late early Carboniferous–early Permian (328–271 Ma). Late Devonian rhyolites originated from partial melting of Meso‐proterozoic accreted lower crust. The crust‐derived rhyolites and coeval mantle‐derived basalts constitute a bimodal volcanic association in the west. Early Carboniferous igneous rocks include syenogranites, monzogranites, gabbro diorites, and gabbros. The granitoids are derived from partial melting of Meso‐proterozoic accreted lower crust. The gabbros and gabbro diorites show the spatial variation in zircon εHf(t) values (−0.53 to +0.84 in the east and +12.3 to +13.5 in the west), which imply that they were mainly derived from metasomatized mantle wedge and asthenosphere mantle, respectively. These characteristics indicate that northwest‐towards high‐angle subduction of the Paleo‐Asian Ocean plate beneath the united Xing'an–Erguna Massif induced arc magmatism in the east and back‐arc magmatism (similar to back‐arc rift) in the west during the Late Devonian to early Carboniferous. Late early Carboniferous–early Permian sub‐alkaline and alkaline igneous rocks are characterized by multiple sources, such as the depleted mantle, juvenile lower crust, and thickening lower crust. Their temporal variations in geochemical characteristics imply that the central Great Xing'an Range was situated under a transitional setting from syn‐collisional to post‐collisional during the late early Carboniferous to early Permian. Using the combined insight from lithofacies palaeogeography and regional magmatisms, we suggest amalgamation of the united Xing'an–Erguna and Songnen–Zhangguangcai Range massifs occurred during the late early Carboniferous to late Carboniferous. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We present new zircon U–Pb–Hf and whole-rock geochemical data for volcanic rocks along the eastern margin of the Xing'an Massif of NE China in order to further our understanding of the history of subduction towards the SE and the spatial extent of the Mongol–Okhotsk tectonic regime. Zircon U–Pb dating indicates that the Triassic volcanism in the Xing'an Massif occurred in two stages during the Middle (ca. 242 Ma) and Late (ca. 223–228 Ma) Triassic. Middle Triassic basaltic andesites in the Heihe area have an affinity to arc-type volcanic rocks. The zircon ε Hf (t) values (+ 8.5 to + 12.7) suggest that the primary magma was generated by the partial melting of a relatively depleted mantle wedge that had been metasomatized by subduction-related fluids. The Late Triassic andesites in the Handaqi area exhibit geochemical affinities to high-Mg adakitic andesites. Their zircon ε Hf (t) values (+ 11.5 to + 14.5) and T DM2 ages (313–484 Ma) indicate that their primary magma was derived from the partial melting of a young subducted oceanic crust, followed by interaction with melts derived from mantle peridotite. The Late Triassic basaltic andesites, andesites, and dacites in the Zhalantun–Moguqi area have features similar to those of igneous rocks formed in subduction zones. Their zircon ε Hf (t) values (+ 8.4 to + 15.4) and T DM1 ages (260–542 Ma) indicate that their primary magma was derived from the partial melting of a depleted mantle wedge that had been metasomatized by subduction-related fluids. These data suggest that the Triassic volcanic rocks of the Xing'an Massif formed in an active continental margin setting associated with the southward subduction of the Mongol–Okhotsk oceanic plate towards the SE. We conclude that the Mongol–Okhotsk tectonic regime extended at least as far as the eastern margin of the Xing'an Massif, and that the tectonism spanned the period from the late Permian to early Early-Cretaceous. [ABSTRACT FROM AUTHOR]

This paper presents new results on zircon U–Pb dating, Hf isotope analyses, and trace and major element analyses of Late Devonian and early Carboniferous metavolcanic rocks and early Carboniferous alkaline granites of central Jilin Province, NE China, and uses these data to constrain the late Paleozoic tectonic evolution of the southern margin of the Central Asian Orogenic Belt (CAOB). Zircon U–Pb ages, determined using laser ablation–inductively coupled plasma–mass spectrometry, indicate that Late Devonian Jifanggou Group metarhyolites formed at ∼360 Ma, whereas the early Carboniferous Panling Formation metabasaltic andesites and metarhyolites and the Silengshan alkaline granite formed at ∼340 Ma. The Late Devonian metarhyolites, which exhibit zircon ε Hf ( t ) values of +2.77 to +8.94 and corresponding two-stage model ages ( T DM2 ) ages of 969–1525 Ma, are geochemically similar to I–A-type granites, which is indicative of formation from a primary magma generated by partial melting of juvenile lower crustal material in an extensional environment. The early Carboniferous metabasaltic andesites and metarhyolites are geochemically bimodal, with SiO 2 concentrations of 52.1–61.4 and 72.8–75.1 wt.%, respectively. The former are enriched in Ba, Sr, Th, and U, and are depleted in K, Rb, Nb, Ta, and Ti, whereas the latter are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs; e.g., Rb, K, Th and U), and are depleted in heavy REEs (HREEs), high field strength elements (HFSEs; e.g., Nb, Ta, Ti, and P), and Sr. Zircons from the metabasaltic andesite and metarhyolite units have ε Hf ( t ) values of +9.80 to +12.8 and +11.0 to +13.1, respectively, and corresponding single-stage model ages ( T DM1 ) and two-stage model ages ( T DM2 ) of 468–606 and 584–776 Ma, respectively. Silengshan alkaline granite samples contain minor amounts of riebeckite, are relatively LREEs and LILEs enriched and HREEs and HFSEs depleted, and have markedly negative Eu anomalies, features that are typical of A-type granites. These granite samples have zircons with ε Hf ( t ) values of +8.04 to +13.4 and corresponding T DM2 ages of 549–1037 Ma. These data suggest that the primary magma that formed the early Carboniferous metabasaltic andesites was derived from partial melting of depleted lithospheric mantle material that had been modified by subduction-related fluids, whereas the primary magmas for the coeval metarhyolites and the Silengshan alkaline granite were derived from partial melting of newly accreted crust. These early Carboniferous igneous rocks formed in an extensional setting within the eastern segment of the southern CAOB. [ABSTRACT FROM AUTHOR]

Abstract: LA–ICP–MS zircon U–Pb ages, geochemical and Sr–Nd–Pb isotope data are presented for mafic–ultramafic complexes from the southern Liaoning–southern Jilin area with the aim of determining the nature of the Mesozoic lithospheric mantle and to further constrain the spatial extent of destruction of the North China Craton (NCC). The complexes consist of olivine-websterite, gabbro, dolerite, and gabbro-diorite. Zircons from the complexes show typical zoning absorption, are euhedral–subhedral in shape, and yield high Th/U ratios (1.23–2.87), indicating a magmatic origin. Zircon U–Pb age data indicate that they formed in the Early Cretaceous (129–137Ma). Geochemically, they have SiO2 =44.3–49.8%, MgO=6.8–26.5%, Cr=102–3578ppm, and Ni=31–1308ppm, and are characterized by enrichment in large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depletion in high field strength elements (HFSEs) and heavy rare earth elements (HREEs), as well as a wide range of Sr–Nd–Pb isotopic compositions [(87Sr/86Sr)i =0.70557–0.71119; εNd (t)=−5.4 to −20.1; (206Pb/204Pb)i =15.13–17.85; Δ7/4=−11.49 to 16.00; Δ8/4=102.64–203.48]. Compared with the southern Liaoning mafic–ultramafic rocks, the southern Jilin mafic–ultramafic rocks have high TiO2 and Al2O3 contents, high εNd (t) values, low (La/Yb) N values, low initial 87Sr/86Sr ratios, and low radiogenic Pb isotopic compositions. These findings indicate that the primary magmas of the southern Jilin complexes were derived from lithospheric mantle that was previously metasomatized by a melt derived from the delaminated ancient lower crust, whereas the primary magmas of the southern Liaoning complexes originated from partial melting of a lithospheric mantle source that was previously modified by melt derived from the broken-off Yangtze slab. Therefore, the lateral extent of the NCC destruction should include the southern Liaoning–southern Jilin area. [Copyright &y& Elsevier]

This paper presents new zircon U–Pb, Hf isotope, and whole-rock major and trace element data for early Paleozoic igneous rocks of the Lesser Xing'an Range, NE China, in order to constrain the early Paleozoic tectonic evolution of the eastern Central Asian Orogenic Belt (CAOB). Zircon U–Pb dating indicates that early Paleozoic magmatic events within the northern Songnen–Zhangguangcai Range Massif (SZM) can be subdivided into four stages: Middle Cambrian (~ 505 Ma), Late Cambrian (~ 490 Ma), Early–Middle Ordovician (~ 470 Ma), and Late Ordovician (460–450 Ma). The Middle Cambrian monzogranites are K-rich, weakly to strongly peraluminous, and characterized by pronounced heavy rare earth element (HREE) depletions, high Sr/Y ratios, low Y concentrations, low primary zircon ε Hf (t) values (− 6.79 to − 1.09), and ancient two-stage model (T DM2 ) ages (1901–1534 Ma). These results indicate derivation from partial melting of thickened ancient crustal materials that formed during the amalgamation of the northern SZM and the northern Jiamusi Massif (JM). The Late Cambrian monzonite, quartz monzonite, and monzogranite units are chemically similar to A-type granites, and contain zircons with ε Hf (t) values of − 2.59 to + 1.78 and T DM2 ages of 1625–1348 Ma. We infer that these rocks formed from primary magmas generated by partial melting of Mesoproterozoic accreted lower crustal materials in a post-collisional extensional environment. The Early–Middle Ordovician quartz monzodiorite, quartz monzonite, monzogranite, and rhyolite units are calc-alkaline, relatively enriched in light REEs (LREEs) and large ion lithophile elements (LILEs; e.g., Rb, Th, and U), depleted in HREEs and high field strength elements (HFSEs; e.g., Nb, Ta, and Ti), and contain zircons with ε Hf (t) values of − 7.33 to + 4.98, indicative of formation in an active continental margin setting. The Late Ordovician alkali-feldspar granite and rhyolite units have A-type granite affinities that suggest they formed in an extensional environment. A comparison of early Paleozoic magmatic events and Hf isotopic model ages between the northern SZM and the JM indicates that these two massifs have similar histories of Mesoproterozoic and early Paleozoic crustal accretion and reworking, although the SZM contains much older crustal materials than the JM. [ABSTRACT FROM AUTHOR]

To constrain the Permian–Early Mesozoic tectonic evolution of the eastern segment of the Paleo-Asian Ocean, we conducted zircon U–Pb dating and whole-rock geochemical analyses on six middle Permian–Middle Triassic intrusive plutons in central–eastern Jilin Province, NE China. Zircons from the six plutons display distinct oscillatory zoning and striped absorption in cathodoluminescence (CL) images, and Th/U ratios of 0.11–1.41, indicating a magmatic origin. Zircon U–Pb dating indicates that the intrusive rocks formed in the middle Permian (ca. 260 Ma) to Middle Triassic (ca. 245 Ma). In central–eastern Jilin Province, the middle Permian and Middle Triassic plutons are composed mainly of strongly deformed monzogranites with affinities to adakitic rocks, which are formed from partial melting of thickened mafic lower crust. In contrast, the late Permian–the Early Triassic plutons in central–eastern Jilin Province consist of a bimodal association (including gabbros and granitoids) and deformed monzonites, which typically form in extensional settings. These observations, along with the results of previous studies on early–middle Permian granitoids in western Jilin Province, indicate that the eastern segment of the Paleo-Asian Ocean underwent the initial closure in central–western Jilin Province during the middle Permian and the final closure in eastern Jilin Province in the Middle Triassic. [ABSTRACT FROM AUTHOR]

Abstract: Zircon U–Pb dating and whole-rock geochemical analysis have been undertaken on Late Paleozoic–Early Mesozoic intrusive rocks of central Jilin Province, NE China, with the aim of constraining the tectonic evolution of the eastern segment of the northern margin of the North China Block (NCB) during the Late Paleozoic–Early Mesozoic. Zircon U–Pb dating indicates that Late Paleozoic–Early Mesozoic magmatic events can be subdivided into four stages: Middle Permian (~270Ma), Late Permian (259–255Ma), Early Triassic (~249Ma), and Late Triassic (~222Ma). The Middle Permian magmatic event formed peraluminous garnet-bearing monzogranites, indicative of formation under a compressional tectonic regime related to collision between the NCB and the Songnen–Zhangguangcai Range Massif. The Late Permian magmatic event formed gabbros and syenogranites, a bimodal association that is typical of magmatism within post-collisional extensional setting. The Early Triassic magmatic event formed adakitic monzogranites, suggesting that they formed from magmas derived from partial melting of a thickened mafic lower crust. The Late Triassic magmatic event formed a series of mafic–ultramafic intrusive rocks, together with coeval granitoids in adjacent regions, and make up a typical bimodal association suggesting that they formed under an extensional environment related to the final amalgamation of the NCB and the Songnen–Zhangguangcai Range Massif. Taken together, we conclude that the northern margin of the NCB underwent multiple orogenic events between the Middle Permian and the Late Triassic, with final amalgamation of the NCB and the Songnen–Zhangguangcai Range Massif occurring in the Early Triassic, an event that led to the final suturing of the Solonker–Xra Moron–Changchun zone. [Copyright &y& Elsevier]

This study presents new zircon U–Pb–Hf and whole-rock geochemical data for intrusive rocks in the Xing'an Massif of NE China, with the aim of furthering our understanding of the evolution and spatial influence of the Mongol–Okhotsk tectonic regime. Zircon U–Pb dating indicates that five stages of Mesozoic magmatism are recorded in the Xing'an Massif, namely during the Middle Triassic (~237 Ma), the Late Triassic (~225 Ma), the Early Jurassic (~178 Ma), the Middle Jurassic (~168 Ma), and the late Early Cretaceous (~130 Ma). The Middle Triassic–Early Jurassic intrusive rocks in the Xing'an Massif are dominantly granodiorites, monzogranites, and syenogranites that formed from magma generated by partial melting of newly accreted continental crust. Geochemistry of the Middle Triassic–Early Jurassic granitoid suites of the Xing'an Massif indicates their formation at an active continental margin setting, related to the southwards subduction of the Mongol–Okhotsk oceanic plate. The Middle Jurassic monzogranites in the Xing'an Massif are geochemically similar to adakites and have ε Hf (t) values (+3.8 to +5.8) and Hf two-stage model ages (T DM2 ; 979–850 Ma) that are indicative of derivation from magma generated by partial melting of thickened juvenile lower crust. The Middle Jurassic monzogranites formed in a compressional setting related to the closure of the Mongol–Okhotsk Ocean. The late Early Cretaceous intrusive rocks in the Xing'an Massif are dominated by A-type granitoids that are associated with bimodal volcanic rocks, suggesting their formation in an extensional environment related to either (i) delamination of a previously thickened region of the crust, associated with the Mongol–Okhotsk tectonic regime; (ii) the subduction of the Paleo-Pacific Plate; or (iii) the combined influence of these two tectonic regimes. [ABSTRACT FROM AUTHOR]

Abstract: LA-ICP-MS zircon U–Pb dating and geochemical data have been obtained from five representative mafic–ultramafic intrusions in the Lesser Xing''an–Zhangguangcai Range, NE China, with the aim of improving our understanding of the Mesozoic tectonic evolution in the region, and in particular, determining the time of initiation of the circum-Pacific tectonic system. The selected zircons exhibit striped absorption in cathodoluminescence (CL) images and have high Th/U ratios (0.20–3.16), indicating a magmatic origin. The zircon U–Pb dates indicate that most of these magmatic zircons (other than a few relics that were captured and entrained in the magma) formed in the late Early Jurassic (186–182Ma), and not as previously supposed in the Middle Caledonian. The five mafic–ultramafic plutons are composed of olivine-gabbro, hornblendite, gabbro, hornblende-gabbro, and gabbro–diorite. The olivine-gabbro and hornblendite display cumulate textures, implying that fractional crystallization of olivine and plagioclase took place during magma evolution. These mafic–ultramafic igneous rocks have SiO2 =37.3%–55.7%, MgO=3.05%–13.3%, Al2O3 =11.8%–23.8%, Mg#=42–69 [Mg#=100Mg/(Mg+Fe2+ total)], and δEu=0.88–1.32, and they display three types of rare earth element (REE) distribution patterns: right-slipped, flat patterns, or dome-like. The trace element spider diagrams show that the rocks are enriched in large ion lithophile elements (LILEs) such as Ba, K, and Sr, and depleted in high field strength elements (HFSEs) such as Nb, Ta, Zr, and Hf. The zircons have εHf (186–182Ma)=+2.7 to +12.0, and TDM1 =366–732Ma. The geochemical data indicate that the Early Jurassic mafic magma originated in an extensional environment from the partial melting of a depleted mantle wedge that had been metasomatized by fluids released from a fossil subducted slab. These data, combined with information on the spatial variation of coeval igneous rocks, indicate that the formation of the Early Jurassic mafic–ultramafic rocks in the Lesser Xing''an–Zhangguangcai Range was related to the subduction of the Paleo-Pacific Plate beneath the Eurasian continent, and this event would mark the beginning of the circum-Pacific tectonic system. [Copyright &y& Elsevier]