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Based on the comparison of zircon ages with source terranes, they inferred that the likely source for Cenozoic zircon grains was the Eastern Alkaline Province of Mexico, which comprises various volcanic fields of Cenozoic age. Armstrong-Altrin et al. (2021) reported the detrital zircon grain surface features, chemistry, and U-Pb ages in the Chachalacas beach sediments, Gulf of Mexico. Armstrong-Altrin et al. (2020) discussed the U-Pb ages of detrital zircon grains, which we reported from the Chachalacas beach in the western Gulf of Mexico. [Extracted from the article]

We thank Patil Pillai et al. for preparing a critique on our article (Joy et al., 2018). Patil Pillai et al. contest the analytical procedure utilized for the carbonates and "geological information" documented in our research article and raise concerns on our conclusions. We hereby provide our reply to each of their comments. [ABSTRACT FROM AUTHOR]

This special issue (Volume 3) belongs to the special issues on the orogens along the Silk Road. We selected 34 papers to focus on the mineral deposits, orogeny‐links, geochemistry, geochronology, and environments related to the Tianshan Orogen of the Silk Road. We hope that these papers will highlight more geological research along the Silk Road to promote the construction and development of the Road and Belt. [ABSTRACT FROM AUTHOR]

Detrital single‐grain zircon U–Pb geochronology is a powerful tool for provenance studies if information on the source rocks is available. This paper proposes a new source‐rock classification tool that uses the degree of annealing of radiation damage in detrital zircon; the annealing is expressed by the relationship between the width (full‐width at half‐maximum; FWHM) of the v3[SiO4] Raman band at ~1008 cm−1 and the calculated α‐dose. The host rocks of the zircons are classified into three types according to their emplacement process and/or thermal history: volcanic and rapidly cooled plutonic and high‐grade metamorphic rocks (type 1); rocks with hydrothermal zircons (type 2); slowly cooled igneous and metamorphic rocks (type 3). We construct a naive Bayes prediction model by training it with a collection of zircons of known types. The unknown zircons are assigned a probability of derivation from a specific host‐rock type. This classification scheme is best used as an accessory tool in provenance studies that apply detrital zircon U–Pb geochronology. [ABSTRACT FROM AUTHOR]

This paper reports two types of basalt that have different ages (Carboniferous and Permian) but occur next to each other in the northern part of the Changning–Menglian accretionary wedge, southwestern China. We use the geochronology and geochemical data to evaluate the tectonic evolution of the Palaeo‐Tethys during this period. Zircon grains from the mafic‐ultramafic rocks associated with the Permian basalts in the Xiaomengtai area yield a U–Pb age of 281 Ma and εHf(t) values from +9.2 to +12.8. The Permian mafic‐ultramafic rocks and the associated basalts are all characterized by normal mid‐ocean ridge basalt (N‐MORB)‐like chondrite‐normalized rare earth elements patterns, moderately negative Nb‐Ta anomalies in the mantle‐normalized immobile incompatible trace element patterns, and positive εNd(t) values from +4.2 to +6.5, which are consistent with the geochemical characteristics of mafic‐ultramafic rocks in supra‐subduction zone (SSZ)‐type ophiolite. On the contrary, the Carboniferous basalts, which are associated with marine carbonates, are characterized by light REE enrichments, slightly positive Nb‐Ta anomalies, and εNd(t) values from +2.8 to +4.0. These features are similar to those of typical oceanic island basalts (OIBs) worldwide. Modelling results using REEs show that the parental magmas for the Carboniferous OIBs and the Permian basalts were likely derived from mantle peridotites at the depths of garnet and spinel stability, respectively, consistent with the formation depth of these two different types of basalt globally. The occurrence of these two different types of mafic‐ultramafic rocks with significantly different ages in the same area supports the view that they are the remnants of the accreted Palaeo‐Tethys oceanic crust. The Carboniferous OIBs are considered to be parts of an OIB‐carbonate seamount chain that originally formed in the southern part of the Palaeo‐Tethys. The Permian mafic‐ultramafic rocks are regarded as fragments of SSZ‐type ophiolites that were present in the northern part of the Palaeo‐Tethys. These different pieces of oceanic crust were accreted to the Simao–Indochina continental Block by subduction between the Late Permian and the Triassic. [ABSTRACT FROM AUTHOR]

The present paper addresses petrography, geochemistry and Ar‐Ar geochronology of a significant number of mafic dykes from the Paleo‐ to Neoarchean Bundelkhand Craton in central India. The majority of the dykes are NW‐SE oriented (with a few NE‐SW and ENE‐WSW) with tholeiitic, sub‐alkaline and basalt to basaltic andesite composition. The trace element geochemistry of these dykes indicates an island arc setting during emplacement. The Ar‐Ar mineral dating (plagioclase) of three representative dykes reveals an emplacement age between 1.53 and 1.46 Ga. This finding and earlier reports (2.1–1.73 Ga) point to sustained mafic magmatism throughout the Bundelkhand Craton in a preferred structural orientation between 2.1 and 1.46 Ga. Mafic magmatism was episodic and can be linked to the perpetual subduction accretion processes between the central Indian Archean continents during the development of the Columbia supercontinent. The mafic dykes were emplaced at 45° to the maximum compression direction (E‐W), that is, along the line of no finite longitudinal strain. This time equivalent widespread NW‐SE and NE‐SW trending mafic dyke system is also relatable along the adjacent continents (Singhbhum, Bastar) and thus opened up a new paradigm for the dyke's emplacement across the Indian cratons. [ABSTRACT FROM AUTHOR]

The Zhaojinggou Nb–Ta deposit is one of large rare metal deposits newly discovered in the northern margin of the North China Craton in recent years. This paper reports petrography, petrochemistry, columbite‐group minerals U–Pb chronology study of the amazonite granitic pegmatite (AGP) exposed in this deposit, and composition of columbite‐group minerals and biotite are obtained by electron probe microanalyzer and LA‐ICP‐MS. Eighteen analyses of columbite‐group minerals yielded weighted mean 206Pb/238U age of 116.9 ± 1.4 Ma. The crystallization temperature of biotite is 630–650°C, and the oxygen fugacity is 10−17–10−18 bars. The biotite has low MgO contents and high Rb, Rb/Sr, and FeOT/(FeOT + MgO) ratios. The AGP has extremely low MgO, Cr, Co and Ni contents, with Nb/Ta ratios range from 1.63 to 9.05 and Rb/Sr ratios range from 303.30 to 648.90, and obvious 'M' type tetrad effect of rare earth element indicating that the formation of the AGP is related to crust‐derived magma. The contents of Nb2O5 and FeO decrease, while the Ta2O5 and WO3 contents, Mn# and Ta# values increase gradually from the core to the rim of columbite‐group minerals. Some columbite‐group minerals have unobvious oscillatory zoning, and some have a clear bright zoing with high Ta contents on the rim, indicating that the genesis of Zhaojinggou Nb–Ta deposit is mainly magmatic crystallization differentiation, accompanied by hydrothermal autometasomatism in the late stage. [ABSTRACT FROM AUTHOR]

The North Qinling Orogenic Belt (NQB) records the pivotal geological information for understanding the Palaeozoic evolution of the Qinling Orogenic Belt (QOB). Previous studies mainly focused on the subduction–collision process along the Shangdan suture zone before the Early Devonian. However, as the significant interim period between the Early Palaeozoic and Mesozoic orogeny, the Late Palaeozoic tectonic evolution of the NQB remains poorly understood. Fortunately, the Carboniferous magmatic rocks discovered this time provide substantial geological evidence for revealing the Late Palaeozoic tectonic history of the Qinling Orogenic Belt. This paper will provide a detailed analysis of zircon U–Pb ages, geochemical characteristics and Sr‐Nd‐Hf isotopic compositions of Carboniferous rocks. The Carboniferous magmatic rocks are categorized as highly differentiated S‐type granite and monzodiorite, formed at 350 ± 2.4 Ma and 353 ± 5.2 Ma, respectively. The granite shows weak peraluminous (A/CNK = 1.02–1.11) and shoshonite nature. Based on the isotopic composition and trace element characteristics, we propose that the Qinling Group paragneiss is the primary source of the Carboniferous granite. Monzodiorite is characterized by enriched LREEs and LILEs (Ba, K and Pb), depleted HFSEs (Th, Nb, Ta and Ti) and enriched Sr‐Nd isotopic composition. Monzodiorite magma source region consists of continental crustal material and lithospheric metasomatized mantle. Carboniferous magmatic rocks are the product of an extensional tectonic setting, which indicates the NQB tectonic regimes transition from compression to extension during the Carboniferous. [ABSTRACT FROM AUTHOR]

This paper presents new zircon U–Pb–Hf isotopic and whole‐rock geochemical data for early Paleozoic–early Mesozoic igneous rocks from the Zhangguangcai Range, which are used to provide constraints on the petrogenesis and tectonic setting of these rocks and on the tectonic evolution of the eastern Songnen Massif. We dated five igneous rocks from the Zhangguangcai Range of the eastern Songnen Massif, namely, a late Cambrian (~489 Ma) syenogranite, a middle Silurian (~431 Ma) dacite, a Middle Triassic (~247 Ma) gabbro‐diorite and two Late Triassic (214–210 Ma) rhyolites. The late Cambrian syenogranite, middle Silurian dacite and Late Triassic rhyolites have high SiO2 and (Na2O + K2O) contents and low Mg# values. These four rocks are enriched in light rare earth elements (LREEs) and large‐ion lithophile elements (LILEs) but depleted in heavy REEs (HREEs) and high‐field‐strength elements (HFSEs). In addition, the εHf(t) values and TDM2 ages of zircons from these rocks range from −1.31 to +5.88 and from 1264 to 896 Ma, respectively. These data suggest that their primary magma was derived from partial melting of the juvenile mafic lower crust that was generated during the Mesoproterozoic–Neoproterozoic. The Middle Triassic gabbro‐diorite has low SiO2 and high MgO, Sc, Co, Cr and Ni contents and is enriched in LILEs and LREEs but depleted in HREEs and HFSEs such as Nb and Ta. Combining these features with the zircon εHf(t) values of the gabbro‐diorite, which range from +0.02 to +1.79, the primary magma of this rock is inferred to have been derived from partial melting of an isotopically depleted lithospheric mantle. The late Cambrian syenogranites and the middle Silurian dacites are weakly peraluminous and are classified as medium‐ to high‐K calc‐alkaline series, indicating that they formed in an active‐continental‐margin setting. The Middle–Late Triassic igneous rocks exhibit a bimodal igneous rock association, suggesting that they formed within an extensional environment. Combining our new results with previous findings, the early Paleozoic–early Mesozoic tectonic evolution of the eastern Songnen Massif is revealed. During the early Cambrian–early Silurian, the oceanic plate between the southern Songnen and southern Jiamusi massifs subducted westward beneath the Songnen Massif. The amalgamation between the southern Songnen and southern Jiamusi massifs occurred during the middle Silurian, and the southeastern Songnen Massif was in a post‐collisional extensional setting during the Devonian. During the late Carboniferous–Triassic, the Zhangguangcai Range was in an extensional environment, and the Mudanjiang Ocean started to open along the Jiayin–Mudanjiang Fault, separating the Songnen and Jiamusi massifs during the Middle–Late Triassic. [ABSTRACT FROM AUTHOR]

The Trans‐North China Orogen (TNCO) is a part of the North China Craton (NCC) and together provides a classic example of lithospheric destruction. The Pandao granites outcropping in the Wutai Mountains area provide a window to investigate the Mesozoic magmatism in the TNCO. Here, this paper presents the new zircon geochronology, whole‐rock geochemistry, and zircon Hf isotope data for the Pandao granites to discuss their petrogenesis and tectonic implications. The Pandao granites are mainly composed of light‐red medium‐ to coarse‐grained biotite granite and light‐grey fine‐ to medium‐grained biotite granite. Zircon U–Pb ages of 110.05 ± 0.67 Ma and 108.35 ± 0.81 Ma suggest that the Pandao granites were crystallized in the Early Cretaceous. The Pandao granites are classified as high‐K calc‐alkaline and weak peraluminous series. The rocks display abundance in large‐ion lithophile elements (LILE) and light rare‐earth elements (LREE) but show depletion in high‐field‐strength elements (HFSE) and heavy rare‐earth elements (HREE), with strong negative Eu anomalies. The classification diagrams indicate that the Pandao granites are A‐type granites and thus belong to the A1 subtype, formed in an intraplate extensional environment. The Pandao granites have homogeneous zircon Hf isotopic compositions. Their zircons have negative εHf(t) values (−19.1 to −17.1) and old Hf isotope crustal model ages (2,250–2,375 Ma), suggesting that the Pandao granites were formed by partial melting of the Paleoproterozoic lower crustal material. Therefore, it is suggested that the Pandao granites were formed under an intraplate extensional tectonic environment of remote effect due to the ancient Pacific Plate subduction and retreat beneath the Eurasian continent. The TNCO was influenced by the subduction and retreat of the ancient Pacific Plate in the late Early Cretaceous. [ABSTRACT FROM AUTHOR]

The Kelameili suture located between the eastern Tianshan Junggar Plate and the Harlik island arc in east Tianshan. This suture is well known as identifying the Kelameili ophiolite and the Tucker Takezale ophiolitic melange. This paper first reports a new discovery of the Shihuiyao ophiolite, which is 70 km away from the Takezale ophiolitic mélange to the east. It is mainly composed of the variable serpentinized peridotite, metagabbro, and minor siliceous rocks. The serpentinite and gabbros are characterized by high content of Al2O3 and normal mid‐ocean ridge basalt (N‐MORB)‐type rare earth element compositions. These rocks also show a typical characteristic of origin of island arc setting with depletion of high‐field strength element (HFSE) and enrichment of large‐ion lithophile element (LILE). The LA‐ICP‐MS dating of zircon grains from gabbros gave a weighted mean 206Pb/238U age of 352 Ma, which was interpreted to represent the age of the Kelameili Ocean. This paper provided an important constraint on the tectonic evolution of the Kelameili Ocean. [ABSTRACT FROM AUTHOR]

Banded iron formations (BIFs), granites and diabases are extensively distributed in the Kuluketage block of the northeast Tarim Craton. Here we report laser ablation–inductively coupled plasma–mass spectrometry (LA‐ICP‐MS) zircon U–Pb ages and whole‐rock elemental data for these rocks. The detrital zircons from the BIFs show a peak age of 2.0–1.8 Ga with a weighted mean age of 1945 ± 10 Ma (MSWD = 0.77), and the zircons from the granite give an upper intercept age of 1974 ± 27 Ma (MSWD = 1.05). The trace element features suggest that the Asitingbulake granite, which belongs to the I‐type granite, may originate from the re‐melting of continental crust in a ~1.95 Ga collisional orogenic setting. Recently, the 2.0–1.8 Ga continuous magmatic and metamorphic events which are contemporaneous with the global orogenic event have been reported in the Kuluketage block and other massifs around the Tarim Craton (e.g. Central Tianshan, Dunhuang, Quanji, Altyn Tagh, West Kunlun). Based on the previous geochronological data, two 2.0–1.8 Ga orogens associated with the assembly of the Columbia supercontinent can be identified along the north and south margins of Tarim Craton: (1) the north Tarim Orogen, Central Tianshan–Kuluketage–Dunhuang orogenic belt and (2) the south Tarim Orogen, West Kunlun–Altyn Tagh–Aketashtage–Quanji orogenic belt. Additionally, this paper reports a new zircon U–Pb age of 1497 ± 21 Ma (MSWD = 0.96) from the Baowenbulake diabase dykes where the trace element features suggest that the parental magma of Baowenbulake diabases is derived from the mantle in an intra‐plate rifting or extensional setting. The ~1.5 Ga diabases from northwest Tarim corresponded to a major episode of mafic magmatism during the early Mesoproterozoic period identified in other crustal fragments of Laurentia, Siberia, Greater Congo, South China and North China Craton and probably belong to one of the three major large igneous provinces associated with the breakup of the Mesoproterozoic Columbia supercontinent. The data from this paper provide important constraints on the configuration of the Tarim Craton during the assembly and breakup of the Columbia supercontinent. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Lower Jurassic clastic rocks in the Qiangtang Basin, northern Tibet, are generally regarded as the early sediments of the new Mesozoic Qiangtang Basin (Late Triassic to Early Cretaceous). However, little attention has been paid to the palaeoenvironment, provenance, and tectonic setting of this unit. The QZ‐16 well, located in the east of the northern Qiangtang Basin, firstly recovered the Lower Jurassic strata (Quemo Co Formation) in the Qiangtang Basin. In this paper, the whole‐rock major‐trace elemental characteristics of 34 mudstone samples and detrital zircon geochronology of one sandstone, collected from the Quemo Co Formation of the QZ‐16 well, are reported in order to infer the palaeoenvironment, provenance, and tectonic setting. Quemo Co mudstones are dominated by SiO2 and Al2O3, while Fe2O3, CaO, K2O, and MgO are the second most abundant oxides. They are generally characterized by high REE concentrations, enrichment in light rare earth elements (LREEs), marked negative Eu and Ce anomalies. The REE contents of the mudstones are mainly controlled by terrigenous detrital minerals input. The Lower Jurassic mudstones have relatively high chemical index of alteration (79.1–83.6) values, indicating moderate to high degree of chemical weathering conditions of the source area. Sr/Ba and Rb/K ratios reflect that the marine transgression impact was limited and the mudstones were generally deposited in a brackish water environment. Major, trace, and REE contents indicate that the mudstones were mainly derived from intermediate igneous rocks with subordinate felsic igneous rocks. Prominent age peaks at ca. 200 ~ 400 Ma, 700 ~ 970 Ma, 1,700 ~ 1,900 Ma, and 2,100 ~ 2,700 Ma of the detrital zircon grains suggest that the Lower Jurassic clastic rocks were derived from the Central Qiangtang and Songpan–Ganzi complex. Moreover, tectonic discrimination diagrams based on major and trace elements show that the source of the Lower Jurassic sediments were most likely derived from a collision tectonic setting. [ABSTRACT FROM AUTHOR]

The Qingchengzi Pb–Zn–Au–Ag–Mo polymetallic ore field located in the Liaodong Peninsula, Liaoning Province, China, is spatially associated with multiple magmatism, which provide a classic example for studying the multiple tectonic and metallogenetic events. In this paper, we report some new geochemical and geochronological data of igneous rocks in the Qingchengzi ore field, including diabase, lamprophyre, microdiorite, granite porphyry, and quartz porphyry. Zircon U–Pb dating yielded the formation ages of these rocks as Triassic, Jurassic, and Early Cretaceous. Low‐Mg adakitic granite porphyries formed at 233 Ma have zircon εHf(t) values of −17.7 to −14.5, suggesting that they were mainly derived from partial melting of thickened lower crust. Mafic dykes formed during 226–203 Ma have zircon εHf(t) values of −28.6 to −12.8, suggesting that they were mainly derived from partial melting of ancient lithospheric mantle. Zircons from the 168Ma Jurassic diabase have high Nb/Ta and low Nb/Th ratios, with zircon εHf(t) values of −25.2 to −18.5. This suggests that ancient lithospheric mantle was influenced by melts/fluids from the subducted Palaeo‐Pacific Plate. The Early Cretaceous microdiorites (126 Ma) are high‐Mg adakite rocks, with zircon εHf(t) values of −27.3 to −19.6. Melting of delaminated eclogitic lower crust might produce these high‐Mg adakitic microdiorites. The upwelling asthenosphere could heat the residual lower crust to form the quartz porphyries. The Early Cretaceous diabase (100 Ma) shows low Nb/Ta and high Nb/Th ratios, with zircon εHf(t) values of −0.7 to 5.8, implying a depleted mantle source. The characteristics of Triassic–Cretaceous intermediate‐mafic intrusions show that the lithospheric mantle evolved from enriched ancient mantle to depleted juvenile mantle. This transformation of the lithospheric mantle might have resulted from the delamination of the lower crust that was caused by subduction of the Palaeo‐Pacific Plate. Based on the field observation and geochemical data, Au, Pb–Zn–Ag, Mo mineralization in the Qingchengzi ore field show closely spatial and genetic relationship with intrusive rocks, indicating that the Mo, Pb–Zn–Ag mineralization might be related to the Jurassic magmatic activity, whereas Au mineralization related to the Early Cretaceous magma. [ABSTRACT FROM AUTHOR]

Himalayan leucogranites are widely distributed in the North Himalayan gneiss dome (NHGD) and at the top of the Greater Himalayan Crystalline Complex (GHC) and are generally controlled by detachment faults. The ages of these prekinematic, synkinematic, and postkinematic leucogranites can be used to limit the activity of detachment structures (such as the South Tibetan Detachment System, STDS). Research on the STDS activity time in the eastern Himalayas is relatively sparse. In this study, the zircon and monazite U–Th–Pb geochronology of synkinematic and postkinematic leucogranites, which are affected by the STDS and NHGD, in four areas (Lhozhag, Kuju, Xiaozhan, and Cuonadong) in Shannan City, Tibet, China, was measured. The results show that the oldest synkinematic two‐mica granite from Lhozhag, which is affected by the STDS, is 24–25 Ma, so the time of STDS activity is at or slightly earlier than 25 Ma. The youngest synkinematic leucogranite is the garnet‐bearing muscovite granite in Cuonadong at 18.4 Ma. The oldest undeformed postkinematic leucogranite (not affected by the STDS) is the muscovite granite in Xiaozhan at 17.4 Ma. Therefore, the end of STDS activity can be limited to 18.4–17.4 Ma. The STDS includes three forms: detachment fault in the NHGD (northern extension of the STDS), the inner STDS between the GHC and Tethyan Himalayan Sequence, and the outer STDS at the bottoms of synformal klippes. In this paper, the active time limits of the above three kinds of detachment zones are comprehensively summarized. Based on this work, the northward extension (ductile deformation) time of the STDS in the region is considered to be 28–17 Ma. The exhumation of the GHC is mainly controlled by in‐sequence shearing: first, the South Tibet Thrust system (predecessor of the STDS) at the top of the GHC thrust southward at 45–28 Ma, then the High Himalayan Discontinuity fault in the middle of the GHC forms south‐vergent ductile thrusts at 28–17 Ma, and finally, the Main Central Thrust at the bottom of the GHC thrust southward at 17–9 Ma. [ABSTRACT FROM AUTHOR]

Several Palaeozoic ophiolitic mélanges distributed in the West Junggar, Xinjiang, are remnants of the Paleo‐Asian Ocean evolution. They are important keys for studying the component, tectonic evolution, and crust–mantle interaction of the Central Asian Orogenic Belt (CAOB). This paper presents petrology, zircon U‐Pb chronology, geochemistry, and Hf isotope data of mafic rocks from the Dalabute ophiolitic mélange, West Junggar. The zircon U‐Pb chronology data of gabbro in the Dalabute ophiolitic mélange can be divided into two groups. The first group magmatic zircons yield a weighted mean age of 389.7 ± 7.7 Ma. It suggests that gabbros of the Dalabute ophiolitic mélange were formed during the period of Early‐middle Devonian, which represents the main period that the Dalabute back‐arc ocean basin expanded. The second group inherited zircons with ages ranging from 910 to 975 Ma were interpreted as Neoproterozoic materials of basement entered its magmatic source. Geochemical characteristics show that the mafic rocks from the Dalabute ophiolitic mélange can be subdivided into alkaline and tholeiite series. Whole‐rock and Hf isotopic data indicate that alkaline basalts have the signatures of typical OIB and formed in the oceanic island or seamount settings related to mantle plume, which were most likely derived from an enriched mantle source. Besides, tholeiitic rocks exhibit the features of MORB and generated in an immature back‐arc basin in the supra‐subduction zone. Their magmas originated from a depleted mantle that had been metasomatized by subduction‐related fluids and contaminated by materials with crustal nature. Therefore, Dalabute ophiolites are supposed to be generated from a back‐arc oceanic basin, which is relate to intra‐subduction and with mantle plumes developed within it. These results jointly provide convincing evidence for the evolution and property of the Dalabute ophiolite in the West Junggar and further supply reference and base for reconstruct the evolutionary history of the CAOB. [ABSTRACT FROM AUTHOR]

The Tianshan Belt, which lies in the southwest part of Central Asian Orogenic Belt (CAOB), is characterized by abundant ophiolites or ophiolitic mélanges, which are indicators of the existence of oceanic basin can be used for tracking the tectonic evolutionary history of the orogen. The Bindaban (BD) ophiolitic mélange is located in the Central Tianshan Belt, northwest China, which comprises mainly gabbros, diabases, basalts, basaltic lavas (greenschist), and cherts. This paper presents new zircon geochronology, whole‐rock major and trace elements, and Sr, Nd isotope data for mafic rocks in the BD ophiolitic mélanges. In the eastern part of BD ophiolitic mélanges, one normal (N)‐MORB‐type basalt has a U–Pb zircon age of 265.2 ± 1.8 Ma, and one enriched‐MORB‐type dolorite in the western part of BD ophiolitic mélanges has an age of 425.4 ± 3.9 Ma, respectively, indicating either an existing ocean basin from continental rifting to normal oceanic spreading with a long time span from late Silurian to Permain, or two separate ocean basins that formed in late Permian and late Silurian during the Paleo‐Tianshan Ocean evolution. In particular, the 265.2 ± 1.8 Ma age of N‐MORB‐type basalt from BD ophiolitic mélange suggests the youngest oceanic basin (late Permian) existed in southwest CAOB, which reveals that Paleo‐Asian Ocean might last to late Permian, therefore finally closed in or after the late Permian in the North Tianshan area. [ABSTRACT FROM AUTHOR]

Carboniferous magmatism in the Darbut region is critical for understanding the evolutionary history of the accretionary orogenesis of the West Junggar area in the Central Asian Orogenic Belt. In this paper, zircon U–Pb geochronological, whole‐rock geochemical and Sr–Nd–Pb–Hf isotopic analyses of the basalts, basaltic andesite, and dacite from the Carboniferous Tailegula Formation, Darbut region, have been performed. The magmatic zircons from basalt, basaltic andesite, and dacite yield concordia U–Pb isotope ages of 344 ± 4, 347 ± 3, and 340 ± 5 Ma, respectively, which are interpreted as the crystallization ages of these rocks. The basalts and basaltic andesite are characterized by an alkali composition; high Nb/Yb, Th/Yb, Ta/Yb, La/Sm, and Sm/Yb trace element ratios and Pb isotopic ratios; moderate (87Sr/86Sr)i ratios; low (143Nb/144Nb)i ratios; and positive εNd(t) (+0.66 − +4.73) and εHf(t) (+1.7 − +15.2) values. These characteristics indicate that the magmas were derived from mixed mantle sources, that is, enriched mantle sources and high U/Pb ratio mantle (HIMU) component sources with ≤10% partial melting of garnet and spinel lherzolite. The samples display pronounced light rare earth elements (LREEs) and incompatible element enrichment patterns with positive Nb–Ta anomalies and a high Pb content and Nb/La ratios but low (Th/Nb)N ratios and a lower degree of partial melting, implying that these rocks were formed in a continental extensional setting. Based on our results and that of previous studies, we conclude that the early Carboniferous volcanic rocks in the Darbut region formed by mantle plume or regional‐scale mantle upwelling in a continental extensional setting after closure of the Junggar Ocean. [ABSTRACT FROM AUTHOR]

This paper reports new zircon U–Pb ages and Hf isotopic compositions of felsic units of the Abor volcanic rocks (AVR) of Eastern Himalayan Syntaxis (EHS), Northeast India, and discusses their relationship to the Kerguelen plume activity. The AVR are bimodal and predominantly constituted by mafic rocks with minor felsic units. Mafic volcanics are identified as basalt and basaltic andesite with light rare earth elements (LREE) enriched and slightly depleted heavy rare earth elements (HREE) pattern without Eu anomalies. Low concentrations of LILE, high contents of Fe2O3, and other incompatible trace elements ratios reflect enriched nature of these mafic volcanics. Felsic volcanic rocks are dacitic to rhyolitic in composition, which have high REE content, high LREE/HREE, and pronounced negative Eu anomalies. Enriched LREE, high Th/Nb, Ce/Nb ratios, and variations in Rb/Zr, K/Rb, La/Sm ratios with negative anomalies of Ba, Nb, Sr, P, Ti in felsic rocks suggest substantial contribution of crustal contamination at the time of eruption. Zircons from felsic units yield an average U–Pb age of ~132 Ma and unradiogenic (ƐHf(t) < 0) Hf isotope values of −7.0 to −13.3 with model ages between 1.5 and 2.1 Ga, suggesting old crustal assimilation in their genesis. The AVR were emplaced in the continental rift tectonic setting, and depth of the magma source is confirmed as near spinel stability zone. The AVR are positively comparable with other flood basalts that were formed due to the Kerguelen plume activity. Therefore, our combined new geochemical and geochronological data show that the AVR were emplaced at early stage (~132 Ma) of eastern Gondwana breakup due to outbreak of the Kerguelen plume. This study thus supports the idea of the Kerguelen plume affecting a large area of Eastern India, Western Australia, and Antarctica during early stage of Gondwana breakup. [ABSTRACT FROM AUTHOR]

As one of the microcontinents dispersed in the South China Sea (SCS), the Xisha microcontinent lacks the petrological evidence of the Cenozoic magmatic activity and basement. Well CK‐2, as a full‐coring kilometre‐scale major scientific drilling in Xisha Islands in the northwestern SCS, drilled through the thick reefal limestone and into the underlying basaltic pyroclastic rocks basement. This paper presents zircon U–Pb age and mineral chemistry of clinopyroxenes from the basaltic pyroclastic rocks. Mineral composition of the clinopyroxenes suggests that most of the clinopyroxenes are composed of diopside, which contains relatively high Al(w (Al2O3) = 5.03%–10.25%) and Ti(w (TiO2) = 2.2%–4.95%). The clinopyroxene discrimination diagrams show that the primary magma is alkaline basalt and likely generated in an intraplate tectonic setting. U–Pb dating of zircons by LA‐ICP‐MS yielded a wide range of ages: 36–33, 116–104, 148–140, 207–196, 255–236, 440, 808–749, and 2,440–1185 Ma. The youngest group has an average age of 35.5 ± 0.9 Ma, which is considered as the maximum age of the basalt eruption. The 2440 ± 19 Ma, which is the oldest zircons in the SCS, are firstly found in the basaltic pyroclastic rocks from the SCS, suggesting that the SCS may contain very old materials. The ages of the inherited zircons are comparable to magmatic activities that occurred around the SCS, implying that they were probably once linked and an integrated part of Gondwana. The ancient continental basement has experienced multistages magmatic events. [ABSTRACT FROM AUTHOR]

The Carboniferous tectonic history of the northern West Junggar of NW China is of key importance for understanding the tectonics of the Altaids. This paper presents a systematic study of the emplacement of the E'min ophiolite, the ages of turbidites, and a stitching granite dike in order to constrain the late Carboniferous oceanic evolution of northern West Junggar. Our field investigation reveals that the Tarbagatay subduction–accretion complex formed by imbrication of turbidites and ophiolitic slices in the Western Tarbagatay Mountain, which is considered as the forearc of the Saur arc in northern West Junggar. Field relationships and zircon geochronology suggest that the emplacement of the E'min ophiolite was later than the minimum time of deposition of hanging wall turbidites, which have a zircon age of 324 Ma, and must be earlier than the crystallization time of a 311‐Ma stitching granite dike that intruded the younger turbidites. The turbidites become younger from north to south, with minimum deposition ages varying from 324 to 309 Ma. The 311‐Ma dike has an adakitic affinity suggesting that it may have formed by magma melted from a subduction slab wedge and from accreted material at ~310 Ma. Therefore, we propose an accretionary arc setting for the Saur arc, with southward migration of the trench and magma front. The 311‐Ma dike has a high Al enrichment and arc‐related geochemical signature suggesting that it was generated by melting of accreted trench sediments. This may indicate that subduction of the Saur arc may have lasted to at least the late Carboniferous. The development of such arc accretion suggests that the formation of the southern Altaids was fundamentally similar to that of accretionary orogens in the western Pacific. [ABSTRACT FROM AUTHOR]

There is ongoing debate as to the genesis of the Lhasa Terrane during the Mesozoic (northward subduction of Yanglu‐Zangbo Tethyan Ocean [YZTO] or southward subduction of Bangong–Nujiang Tethyan Ocean [BNTO]). In this paper, we report a dataset of geochronology, geochemistry, and Sr–Nd–Hf isotopes for the Azhale granitoids in order to elucidate the dominant geodynamic processes of the central subterrane. These rocks are dated at 142.2 ± 1.0 and 136.6 ± 0.6 Ma by zircon LA–ICP–MS method, indicating that these rocks were contemporaneous. In situ zircon Hf isotopic analyses yielded εHf(t) values of −4.2 to −0.1. Geochemically, these samples mostly belong to calc‐alkaline series and show strong enrichments in large‐ion lithophile elements (LILE;e.g., Rb, Ba, and Th) and depletions in high‐field‐strength elements (HFSE;e.g., Nb and Ta), indicating the Azhale granitoids are typically I‐type granite. In terms of isotopic composition, these rocks also have low εNd(t) values (−6.51 to −6.80) and high initial 87Sr/86Sr ratios (0.7078 to 0.7084) relative to melts derived from partial melting of ancient mafic lower crust. We considered that these rocks should be interpreted to have resulted from melting, assimilation, storage, and homogenization (MASH process) above subduction zones. In conclusion, combined with the published and our new data, we argued for the petrogenesis of Early Cretaceous arc‐related granitoids were due to the YZTO lithosphere subducted northward beneath the Lhasa Terrane. [ABSTRACT FROM AUTHOR]

The Lajishan area, located in the South Qilian orogenic Belt, north‐eastern Tibetan Plateau, contains a compositionally diverse range of Cambrian to early Ordovician felsic intrusions that reflect the early Palaeozoic tectonic evolution of the Central Qilian Belt. This paper presents new geochemical, Sr─Nd and Lu─Hf isotopic, and zircon U─Pb data for the Tadong, Huangcaoshan, and Yindonggou plutons in the eastern Lajishan area. LA‐ICPMS U─Pb ages of 517.4 ± 1 Ma for the Tadong pluton which is the first find Late Cambrian granitoids in this area, 467 ± 1 Ma for the Huangcaoshan pluton and 446 ± 1 Ma for the Yindonggou pluton. The new data indicate that the Tadong pluton and Huangcaoshan pluton belong to I‐type granite. Their A/CNK values range from 0.82 to 1.03, suggesting a close relationship with I‐type granitoids. Their trace‐element geochemical characteristics include enrichments in the LILEs, pronounced depletions in Nb and Ta, enrichment of the LREEs relative to the HREEs, and Eu anomalies. These features are similar to those of I‐type volcanic‐arc magmas. Combined with Hf and Sr─Nd isotopic data, The Tadong pluton generated by the mixing of melts was derived from the partial melting of the Precambrian basement and mantle‐derived magmas. The Huangcaoshan pluton was derived from juvenile crust with contamination. The Yindonggou pluton shows A‐type characteristics, their A/NCK is 0.88–1.07, and 10000 × Ga/Al is higher than 2.6. They were characteristic with high Sr, low Y, low Yb, and enriched LREE. Combined with Hf and Sr─Nd isotopic data, the Yindonggou pluton was generated by the partial melting of oceanic slab material and was crustally contaminated associated with slab breakoff. Combined previous research suggests that Tadong pluton and Huangcaoshan pluton formed from southern subduction of the South Qilian ocean into the Central Qilian Belt; the Yindonggou pluton formed in collisional setting. [ABSTRACT FROM AUTHOR]

West Junggar is located at the southwest margin of the Central Asian Orogenic Belt and includes Silurian pillow basalts of the Mayilashan Formation. The petrogenesis and tectonic setting of these pillow basalts are important for the understanding of the tectonic evolution and metallogeny of the West Junggar area. This paper presents geochronological, geochemical, and whole‐rock Sr–Nd–Pb isotope data from the pillow basalts of the Mayilashan Formation. Zircon LA‐ICP‐MS U–Pb dating of a pillow basalt, which is in conformable contact with the chert, suggests that they were erupted at 437.2 ± 2.2 Ma marking the timing of generation of these rocks as Middle Silurian. Geochemically, all the pillow basalts bear the signature of ocean island basalt (OIB), and are characterized by alkaline affinity with high concentrations of TiO2 (3.28–4.12 wt.%), LILE and LREE enrichment and HREE depletion ((La/Yb)N = 5.5–7.3), with very weak Eu anomalies (Eu/Eu* = 0.96–1.06), and no obvious Nb, Ta, or Ti negative anomalies. Their Sr–Nd–Pb isotopic compositions ((87Sr/86Sr)I = 0.7037–0.7051, εNd(t) = 1.9–2.9, 206Pb/204Pbi = 17.74–18.22, 207Pb/204Pbi = 15.48–15.52, and 208Pb/204Pbi = 36.49–37.86) show Dupal‐like isotopic signature of ophiolites in the southern Paleo‐Asian Ocean. These characteristics indicate that the magmas were derived from a deep OIB reservoir, that is, a depleted but slightly heterogeneous asthenospheric mantle source with ~5–15% partial melting of garnet and spinel lherzolite. Our obtained results, in conjunction with previous published data, allow us to suggest that the alkaline pillow basalts formed in a seamount within an intraoceanic setting, where a larger number of seamounts with different ages occurred in the Paleo‐Asian Ocean. [ABSTRACT FROM AUTHOR]

The South Tianshan Terrane (STT) is located in the boundary between the south‐western Central Asian Orogenic Belt (CAOB) and the Tarim Craton and is a key area for understanding the geologic and tectonic history of the craton and the orogenic belt. In this paper, we report detrital zircon ages from the Late Palaeozoic and Mesozoic clastic sedimentary rocks from the southern part of STT. In combination with the U–Pb ages for felsic igneous and meta‐igneous rocks exposed in the STT and adjacent tectonic units, we identify several distinct age populations. Provenance analysis suggests that the detrital zircon grains were predominately derived from the felsic magmatic rocks in the Tarim Craton and South Tianshan Terrane. The pre‐Neoproterozoic age populations may be associated with the early history of the Tarim Craton. Several pulses of Neoproterozoic magmatism are revealed by our dataset, presumably related to the assembly and break‐up of the supercontinent Rodinia. The 995 to 901 Ma detrital zircon grains were likely sourced from magmatic rocks associated with the assembly of Neoproterozoic Tarim to Australia. Among the age population of 886 to 752 Ma, the older group might be related to the subduction‐related magmatism after the assembly of Rodinia, and the younger one records a protracted magmatic event in a continental rift‐related setting associated with the break‐up of Rodinia. Two younger Neoproterozoic age populations (736 to 694 Ma and 665 to 610 Ma), showing narrow spreads with weak peaks, represent the waning stages of igneous activities related to the break‐up of Rodinia. Regarding the Palaeozoic evolution, together with other evidence, our data indicate a two‐stage subduction model for the SW Palaeo‐Asian Ocean. The 490 to 384 Ma age population corroborates the existence of Early Palaeozoic continental arc magmatism at the northern margin of Palaeozoic Tarim generated by the bidirectional subduction of the South Tianshan Ocean. After a ~30 My period of tectonomagmatic quiescence, the second stage is marked by the northward subduction of the South Tianshan Terrane during Late Devonian to Early Carboniferous. The final collision of Tarim and the south‐western CAOB likely occurred during the Late Carboniferous, followed by syn‐ and post‐collisional magmatism, as represented by the 320 to 265 Ma age population. Based on the detrital zircon ages in conjunction with the Hf isotopic features of zircons from Palaeozoic igneous rocks, our study does not support the model of large‐scale Phanerozoic net continental growth in the South Tianshan Terrane. [ABSTRACT FROM AUTHOR]

This paper reports on the petrography, geochemistry, and geochronology of late Mesozoic volcanic rocks in the Wenkutu area of the northern Great Xing'an Range, North‐east China, and discusses the formation age, petrogenesis, and tectonic environment of the Manketouebo, Manitu, Baiyingaolao, and Meiletu formations. Results of Zircon U–Pb dating show that the volcanic rocks in the Wenkutu area were formed during the Early Cretaceous (Manketouebo Formation at 145 ± 1 Ma, Manitu Formation at 141.3 ± 1.7 Ma, Baiyingaolao Formation at 128.7 ± 1.1 Ma, and Meiletu Formation at 129 ± 1 Ma). The Manketouebo, Manitu, and Baiyingaolao formations are dominated by intermediate to acid volcanic rocks that belong to the high‐K calc‐alkaline series, with Eu/Eu* values of 0.38–0.84.They are enriched in light rare earth elements (LREE) and depleted in heavy rare earth elements (HREE). The Meiletu Formation is dominated by intermediate to basic volcanic rocks, belongs to the high‐K calc‐alkaline series, has Eu/Eu* values of 0.89–0.97, and is enriched in Ba, K, Th, U, La, Ce, Sr, Nd, and Hf but relatively depleted in Nb, Ta, Zr, P, and Ti, with no obvious fractionation of LREE and HREE. Results indicate that the magma of the Manketouebo, Manitu, and Baiyingaolao formations had a crustal origin, whereas the Meiletu Formation was sourced from the mantle and subsequently contaminated by crustal materials. The late Mesozoic volcanic rocks in the study area were formed during an orogenic stage, and the compressional environment was caused by subduction of the paleo‐Pacific Plate below the Asian continental plate. [ABSTRACT FROM AUTHOR]

The Kaiyuan tectonic mélange makes up the western part of the Kaiyuan–Yanji Accretionary Complex Belt, NE China, and there has been a long‐standing controversy about its age and tectonic setting. In this paper, we present new zircon U–Pb ages and geochemical data for the mafic rocks of the Lujiapuzi Formation in the Kaiyuan tectonic mélange, and these data provide insights into the tectonic setting during the late Paleozoic and the evolutionary history of the Paleo‐Asian Ocean in the eastern segment of the Central Asian Orogenic Belt (CAOB). SHRIMP U–Pb dating of zircons from samples of albite–actinolite schist and amphibolite yielded a crystallization age of 258 ± 5.5 Ma for the protoliths, suggesting that the protoliths formed during the late Permian. The albite–actinolite schists and amphibolites have similar geochemical characteristics, and they represent metamorphosed basaltic volcanic rocks. Major, rare earth and trace element data show that the mafic rocks have a close affinity with mid‐ocean ridge basalt. REE petrogenetic modelling indicates that the primary magma was generated through the partial melting of a mixed garnet‐ and spinel‐bearing mantle source, and assimilated crustal material and underwent crystal fractionation during ascent. The geochemical features and inherited/xenocrystic zircons in the mafic samples indicate that they formed in a tectonic setting similar to the back‐arc basin. These new findings, together with other previously published data, indicate that the Paleo‐Asian Ocean still existed in the eastern segment of the CAOB during the late Permian to Early Triassic. The Kaiyuan tectonic mélange formed during the Middle Triassic, and its formation may represent the timing of final closure of the Paleo‐Asian Ocean. [ABSTRACT FROM AUTHOR]

The Early Precambrian magmatism in the Archean–Palaeoproterozoic basement Yudongzi Complex is critical for understanding the early crustal formation and evolutionary history of the Yangtze Block in the South China Craton. In this paper, combined zircon UPb geochronological, zircon Hf isotopic, and whole‐rock geochemical studies are carried out on the granitoid gneisses from the Yudongzi Complex, north‐western Yangtze Block. The magmatic zircons from the granitoid gneiss yield a UPb upper intercept age of 2,477±18 Ma, interpreted as the crystallization age of the granitoid gneiss. The granitoid gneiss samples are characterized by high Al2O3 contents, moderate to high Sr/Y, (La/Yb)N and Na2O/K2O ratios, no obvious Eu and Sr anomalies, and depleted Nb, Ta, and Ti values that are similar to those of Archean trondhjemite–tonalite–granodiorite (TTG) suites, indicating that the investigated rocks belonging to TTG‐series rocks. They display pronounced enriched‐LREE patterns with high La/Yb values and relatively high Zr/Sm and Eu/Eu* but low Nb/Ta and Dy/Yb ratios, implying that these rocks were formed by partial melting within amphibolite‐facies conditions with mainly residual amphibole, garnet, and accessory rutile in the magma source. These rocks also display apparently low MgO, Mg#, Ni, and Cr contents, suggesting derivation from partial melting of thickened ancient lower crust. Zircon εHf(t) values from the granitoid gneiss sample vary from −10.1 to −6.9 with TDM2 of ca. 3.59–3.40 Ga, what demonstrates their crustal source nature as well. Thus, taking all these factors together, we propose that the ca. 2.48 Ga granitoid gneisses in the Yudongzi Complex might have been produced by partial melting of ancient crust material under amphibolite‐facies conditions, with primarily residual assemblages of amphibole, garnet, and attached rutile. Taking together our new data and such from previous studies, the Yangtze Block has been probably involved into a significant reworking of ancient crust event during the Early Palaeoproterozoic time. [ABSTRACT FROM AUTHOR]

The tectonic setting of the Alxa Tectonic Belt (ATB) during the late Palaeozoic is highly controversial. The nature and tectonic origin of the late Palaeozoic magmatism in the ATB are key to resolving the current controversy. This paper provides field, petrographic, geochemical, and zircon U‐Pb‐Hf isotopic data for the late Palaeozoic granitoids and volcanic rocks from the south‐western ATB. The granitoids display a wide range of SiO2 contents from diorite, granodiorite, to granites, with widely distributed hydrous minerals such as hornblende and biotite. They are calc‐alkaline to high‐potassium calc‐alkaline, metaluminous with an enrichment of light rare earth elements and large‐ion lithophile elements (LILE), and a depletion of high‐field‐strength elements (HFSE). The presence of mafic‐intermediate enclaves in the plutons suggests the role of crust–mantle interaction in generating the granitoids. The volcanic rocks show "block‐in‐matrix" structures in the field. They are dacite‐porphyry and rhyolite and show calc‐alkaline characteristics with an enrichment of LILE and a depletion of HFSE. Laser ablation inductively coupled plasma mass spectrometry zircon U‐Pb dating shows that the granitoids and enclaves crystallized during ~317–287 Ma and the dacite porphyry formed at ~295 Ma. Hf‐in‐zircon isotopic compositions reveal predominately positive εHf (t) values and Neoproterozoic TDMC ages for the magmatic rocks, indicating mixing between mantle‐derived magma and Precambrian basement during their genesis. The diagnostic field, geochemical data, and isotopic data imply these rocks were generated in a subduction‐related active continental margin setting. The presence of A2‐type granite indicates an extensional environment resulted from slab rollback in a retreating accretionary context can best interpret the large‐scale late Carboniferous–early Permian magmatism in the ATB. Our new data, combined with published data, imply that a large active continental margin existed in the Beishan, Alxa, and the northern margin of the North China Craton, due to the south‐dipping subduction of the Palaeo‐Asian Ocean (PAO) in the late Palaeozoic. Therefore, our data suggest that the PAO did not close until after the early Permian. [ABSTRACT FROM AUTHOR]

This paper presents new geochemical and geochronological data of the Late Mesozoic volcanic rocks in East Mongolia. These volcanic rocks belong to high‐K calc‐alkaline and shoshonitic series and exhibit features of bimodal rocks. The mafic rocks have elevated incompatible trace element concentrations and significantly negative Nb, Ta, and Ti anomalies, with 87Sr/86Sr(i) and ƐNd(t) values of 0.70502–0.70572 and −1.72459 to +1.720736, respectively, which suggest that the mafic magma was derived from a lithospheric mantle source that might have been metasomatized by subduction‐derived fluids, experienced fractional crystallization, and was contaminated by crustal materials. The felsic rocks have similar rare earth element patterns to the mafic rocks but show much more significantly negative Eu and Sr anomalies. The felsic rocks have higher 87Sr/86Sr(i) values of 0.706496–0.71104 than the mafic rocks but similar ƐNd(t) values (−0.28003 to +2.928506) to the mafic ones. These data indicate that the felsic rocks originated from partial melting of a crustal source that is dominated by juvenile mafic rocks. Our new K‐Ar dating, together with previous data, shows that the Late Mesozoic volcanism in East Mongolia took place during the Late Jurassic‐Early Cretaceous between ca. 155 and 99 Ma. The model of back‐arc extension, possibly induced by slab rollback of the westward subducted Pacific Plate and the subduction zone retreat, can explain the geodynamic setting and the eastward younging trend of the Late Mesozoic volcanism in East Mongolia and in adjacent NE China. [ABSTRACT FROM AUTHOR]

The Dongfengshan gold deposit in Heilongjiang Province of China is located at the western margin of the Jiamusi Massif. The mineralization is closely related to the intrusion of the Permian granite porphyry. In this paper, we present new zircon U–Pb ages and whole‐rock geochemical analyses of the granitoids from the Dongfengshan deposit. They are classified as peraluminous high‐K calc‐alkaline to shoshonitic A‐type granites, with enrichment in the large ion lithophile elements (e.g., Rb, U, and Th) and depletion in the high field strength elements (e.g., Nb, P, Ti, and Zr) and clear negative Eu anomalies. The zircons from the granite porphyry are both magmatic and hydrothermal, with the former yielding ages of 281.7 ± 3.3 and 282.1 ± 3.5 Ma that represent the timing of crystallization of this Early Permian pluton. The hydrothermal zircons yield an age of 280.5 ± 0.3 Ma, representing the hydrothermal age, which coincide with the emplacement of the igneous rocks. These data suggest that the Early Permian magmatic and mineralization event led to the formation of the Dongfengshan gold deposit. In comparison, zircons from the monzogranite yield a weighted age of 523.0 ± 6.4 Ma, indicating that magmatism of the study area occurred in the Early Cambrian. On the basis of the regional geological history and the new geochemical and isotopic data from intrusions, we suggest that diagenesis and mineralization of the Dongfengshan gold deposit took place in a postcollisional extensional tectonic setting during the Early Permian. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau and the Himalayan region formed after 55-50 Ma, as a result of the intracontinental collision of the Indian and Eurasian plates, occupying the east-west trending, high-altitude Himalaya and Karakorum ranges in the south and the vast Tibetan Plateau to the north of central Asia. The tectonic evolution of Tibet began between the late Palaeozoic and the Cenozoic, and the Himalayan mountain system evolved in a series of stages beginning 50-35 Ma and is still active. Active tectonics significantly affect upheaval and the rate of erosion in the Himalaya. Therefore, different foreland basins of the Tibetan Plateau (e.g. the Lhasa terrane, the Hoh Xil Basin, the Qaidam Basin, and the Jiuquan Basin) and the Himalayan foreland basins (e.g. Gondwanaland Basin and the Siwalik and Quaternary basin) experience direct effects in terms of tectonic and sedimentary evolution. For the tectonic evolution and provenance analysis of foreland basins in the Tibetan Plateau and the Nepal Himalaya, researchers have adopted various techniques in past studies: This paper discusses petrography, U-Pb geochronology, and seismic reflection. Provenance analyses have illustrated that the sediments of the Southern Tibetan foreland basin (i.e. the Lhasa terrane) derive from the Qiangtang, Tethys Himalaya, and southwest Australia. Similarly, the sediments of the Central Tibetan basin derive from the Qilian, Kunlun-Qimantagh, and the Altyn Mountains; the sediments of northern side of the Tibetan foreland basin, from Qilian Shan Mountain; and the sediments of the Nepal Himalayan foreland basin, from the Tethys, Higher, and Lesser Himalaya. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Palaeo-Asian Ocean (PAO) was located between Siberia and the North China Craton (NCC). The time of its closure, as well as the crustal architecture of the surrounding region, are still uncertain. In this paper, we address these problems using LA-ICP-MS U-Pb ages of zircon grains in three magmatic rocks and three river sand samples of the Guyang area at the northern margin of the NCC. The magmatic rocks yield early Carboniferous crystallization ages of 340.3 ± 7.5 Ma, 331.7 ± 2.3 Ma and 341.1 ± 1.9 Ma for the main granitic pluton, a granodiorite dyke and a diorite enclave, respectively. They were the product of subduction of the PAO underneath the NCC. The detrital zircon U-Pb ages in the river sand samples are dominated by two groups at 2550-2400 and 290-260 Ma, with subordinate groups at 2700-2600, 2000-1800 and 320-300 Ma, dispersed Early Palaeoproterozoic grains and a minor but important group of Cretaceous grains in sands of the Aibugai River. These results, combined with previous geochronological data, permit a re-assessment of the tectonic evolution of the northern margin of the NCC. The events at ~2.5 Ga reflect major crustal reworking and cratonization of the northern margin of the NCC, which then became a stable platform lasting until the Carboniferous. The period between 2.0 and 1.8 Ga was characterized by major collisions related to formation of the Khondalite Belt and the Trans-North China Orogen. In the Carboniferous, subduction of the PAO underneath the northern margin of the NCC developed a zoned distribution of magmatic rocks. The PAO is now constrained to have closed in the Early Permian by the collision of the NCC and Siberia. The youngest group of Cretaceous zircons reflects magmatic events related to lithosphere thinning beneath the Eastern Block of the NCC. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Compostela area is located in the western Trans‐Mexican Volcanic Belt, which consists of volcanic rocks that produced during the Pliocene to Recent volcanism. In this paper, we present petrography, whole‐rock major‐ and trace‐element concentrations, Ar–Ar ages, and Sr–Nd isotopic data of volcanic rocks from the Compostela area in the south of the city of Tepic, Nayarit, Mexico. These volcanic rocks are of intermediate composition and belong to the transitional series: basaltic trachyandesites [52.72–53.94 wt% SiO2; 0.69–2.53 wt% MgO] and subalkaline series: low‐Si [55.11–60.94 wt% SiO2; 0.79–2.74 wt% MgO] and high‐Si [61.60–62.71 wt% SiO2; 0.36–0.80 wt% MgO] andesites. The 40Ar/39Ar dating of two basaltic trachyandesites yields plateau ages of 1.05 ± 0.15 Ma and 1.07 ± 0.17 Ma and the andesites yielded a plateau age of 2.42 ± 0.36 Ma. These results indicate that the studied rocks were formed during the Pleistocene in two discrete episodes. The basaltic trachyandesites show enriched light rare earth elements patterns relative to high rare earth elements [(La/Yb)N = 5.81–8.07] with negligible Eu anomalies. The andesites display enriched large‐ion lithophile elements (Ba, K) with anomalies of Nb (Th/Ce) and Ti in the three groups identified in the subalkaline series. The basaltic trachyandesites appear in a tight cluster of initial 87Sr/86Sr ratios (0.703519–0.703882) as compared to the basaltic andesite 87Sr/86Sr (0.704073) and positive ɛNd(t) values of +5.6 to +3.4, respectively, indicating that the basaltic trachyandesites were derived from intermediate magmas from a shallow mantle source. Geochemical modelling reveals that both basaltic trachyandesite and andesite rocks were derived by a process of crystal fractionation accompanied by assimilation of crustal rocks at the lower or middle level. Geochemical ratios and multidimensional discrimination diagrams, combined with the cross‐section of the subduction zone indicates that basaltic trachyandesites were generated from a rift and/or Ocean Island Basalt‐type source, whereas andesites were generated from a slab‐derived source in a subduction environment. [ABSTRACT FROM AUTHOR]

Due to the lack of corresponding magmatic records, the timing of the opening of the Yarlung–Tsangpo Neo‐Tethyan Ocean remains controversial. The Middle Permian Luerma igneous complex, which is situated in the western Gangdese magmatic belt of the southern Lhasa subterrane, western Tibet, can be divided into four or more rock types, including foid gabbro, amphibole gabbro, monzogabbro, and pyroxene‐bearing monzodiorite. Through zircon U–Pb dating using laser ablation–inductively coupled plasma–mass spectrometry, the age of the Luerma igneous complex is determined to be ~261 Ma. The complex is rich in titanium, iron, magnesium, and total alkalis, with medium to high levels of calcium, potassium and aluminium, as well as low levels of silicon. Therefore, it is classified as a shoshonite–latite rock series. The complex is relatively enriched in light rare earth elements and high‐field‐strength elements, without obvious Eu and Ce anomalies. These rocks exhibit relatively low (87Sr/86Sr)i values, high εNd(t) values, and high εHf(t) values. The geochemical and isotopic characteristics indicate that the magmas are derived from partial melting of the upper mantle in an intraplate tectonic environment. The new data presented here provide supplementary evidence for the initial rifting of the Lhasa terrane from the northern margin of Gondwana during the Middle Permian. These data also confirm that the opening of the Yarlung–Tsangpo Neo‐Tethyan Ocean occurred in the Middle Permian. [ABSTRACT FROM AUTHOR]

Volatile element abundance is a crucial factor triggering mineralization and controlling the enrichment of molybdenum in porphyry deposits. The Chalukou deposit is the largest porphyry Mo deposit in NE China, with an average grade of 0.087% Mo. In this contribution, we present petrology, bulk geochemistry, zircon U–Pb geochronology and Lu–Hf isotopes, and apatite geochemistry for the Chalukou deposit. The intrusive rocks include pre‐mineralization monzogranite, syn‐mineralization quartz porphyry, fine‐grained porphyry and granite porphyry, and post‐mineralization monzogranite and feldspar porphyry. These granitoids are metaluminous to peraluminous, and belong to alkali‐calcic to calc‐alkalic series. Zircon εHf(t) values of granitoids range from +0.2 to +5.7 with corresponding Hf crustal model ages of 805–1170 Ma, indicating a Mesoproterozoic juvenile crustal source modified by mantle‐derived magma. They are characterized by logf(O2) of −16.1 to −9.4, with an average of −12.5, ΔFMQ of +0.8 to +7.9, with an average of +4.5, showing a relatively high oxidation state for the syn‐mineralization magma. The apatites in quartz porphyry have the highest F contents, ranging from 3.61 to 4.62 wt%. At Chalukou, F‐rich magma is conducive to the convection of magma and promotes the efficient separation of differentiation magma, making the magmatic‐hydrothermal fluid circulate many times, eventually resulting in the accumulation of ore‐forming materials on the top of the magma chamber and gradually aggravating mineral enrichment processes. [ABSTRACT FROM AUTHOR]

The Zoige Depression is an important depocenter zone within the northeast of the Songpan-Ganzi Flysch Basin, which is bounded by the South China, North China, and Qiangtang blocks, and also forms the northeastern margin of Tibetan Plateau. This paper discusses the provenance of Middle to Late Triassic sedimentary rocks in the Zoige Depression using petrography, heavy mineral assemblages, and zircon U-Pb geochronology. The results demonstrate that the detritus is derived from multiple source regions. Four distinct parent rocks can be distinguished based on the heavy mineral assemblages and lithic fragments: Provenance 1 predominantly comprises intermediate-acidic volcanic rocks; Provenance 2 includes high-grade metamorphic rocks; Provenance 3 contains a mixture of various detrital components; and Provenance 4 primarily consists of mafic volcanic rocks. The different U-Pb ages of the zircons from the Middle to Late Triassic ranging from 260 to 280, 429-480, 792-974, and 1,800-2,500 Ma represent distinct source regions, which are comparable to the 4 provenances mentioned above: Provenance 1 (260-280 Ma), Eastern Kunlun Orogen; Provenance 2 (429-480 and/or 1,800-2,500 Ma), Qinling orogeny (mainly in North Qinling); Provenance 3 (1,800-2,500 Ma), the North China Block; and Provenance 4 (792-974 Ma), the Yangtze Block. Overall, the detritus in the Middle Triassic (Ladinian, T2zg) primarily originates from the Eastern Kunlun Orogen and North Qinling. During the Late Triassic (Early Carnian, T3z), the southern margin of the North China Block was likely transported westward to the basin by a river network between the North China and South China blocks flowing through the Qinling region, because of the predominance of the detrital zircon age ranging from 1,800 to 2,500 Ma and the occurrence of quartz sandstone with visible enlargement texture. Since the Late Triassic (Middle Carnian, T3zh), great changes have occurred in the source terrains, such as the absence of sources of the Eastern Kunlun Orogen and North China Block and the predominance of Yangtze Block. This drastic change can be explained by the Triassic collision between the South China and North China blocks, and the clockwise rotation of the South China Block progressively closed the basin and uplifted the Qinling orogeny. [ABSTRACT FROM AUTHOR]

A large volume of Early Cretaceous volcanic rocks are exposed in the central Lhasa subterrane, which are essential for models developed for understanding the evolution of Lhasa Terrane. However, the petrogenesis and geodynamic background of these rocks are still in debate. In this paper, we carried out a detailed study on the volcanic rocks of the Zenong Group, including andesite, dacite, and rhyolite from the Coqen area in the central Lhasa subterrane. Zircons from one dacitic tuff yields an age of 115.3 ± 1.1 Ma. All the rocks are enriched in light rare earth elements (LREEs), Th, U, and Pb and depleted in high field strength elements (HFSEs, e.g. Nb, Ta, P, and Ti). The dacite and rhyolite samples are high-K calc-alkaline to shoshonitic and are metaluminous to peraluminous. These felsic samples are characterized by negative ƐNd(t) (−8.9 to −2.1) and ƐHf(t) (−8.1 to −5.6) and have high radiogenic Pb isotopic composition (206Pb/204Pb = 18.6287-19.5578, 207Pb/204Pb = 15.7161-15.7720, and 208Pb/204Pb = 39.1440-40.6253). Particularly, a negative correlation between the ƐNd(t) values and SiO2 contents can be observed in these dacites and rhyolites. Meanwhile, the andesites exhibit similar Sr-Nd-Pb isotopic compositions to dacites and rhyolites (ƐNd(t) = −4.3; 206Pb/204Pb = 18.7119-18.8575, 207Pb/204Pb = 15.7159-15.7203, and 208Pb/204Pb = 39.2944-39.6036). Our new data indicate that different geochemical reservoirs are involved in generating the ca. 115 Ma magmatism in the central Lhasa subterrane. It is likely that dacites and rhyolites are derived from the magma mixing between the ancient basement-derived melts and mantle-derived melts with varying degrees of partial melting. The andesites might originate from partial melting of an ancient lithospheric mantle that have been metasomatized by fluids and/or melts derived from the Tethyan oceanic slab. Our results, together with recent studies, suggest that the Zenong Group volcanic rocks in the Coqen area may represent the magmatic responses to the break-off of the southward subduction of the Bangong-Nujiang Tethyan oceanic slab. [ABSTRACT FROM AUTHOR]

Subduction system in the Qilian orogenic belt experienced the variability of an active continental arc in space and time related to the subduction of the Proto‐Tethys Ocean. Zircon U–Pb geochronology and whole‐rock chemical and Sr–Nd isotopic data of mafic to intermediate dykes in the western part of the Central Qilian belt (WCQB) are used to track magma provenance from compositionally variable reservoirs in the sub‐arc mantle and constrain the magmatic evolution of the rear‐arc at 450–445 Ma. Petrological, whole‐rock chemical and zircon U–Pb dating results reveal that the studied dykes mainly comprise calc‐alkaline lamprophyre (CAL), high Mg# andesitic porphyrite (HMA) and high FeO hornblende gabbro (HFG) with crystallization ages of 447, 453 and 448 Ma, respectively. Among them, CAL and HMA have affinities in high‐K calc‐alkaline suites, high REE contents (∑REE = 131.1–202.3 ppm) with high LaN/YbN values (6.77–17.99), enriched in large‐ion lithophile elements (LILE, e.g., Rb and U), and depleted in high‐field‐strength elements (HFSE, e.g., Nb, Ta, and Ti). They also have high Th/La (0.20–0.46), Th/Nb (0.67–1.64) and Th/Yb (3.88–14.11) ratios, and relatively high whole‐rock initial 87Sr/86Sr ratios (0.707469–0.708493) and εNd(t) values (−4.7 to −3.1). Whereas, HFG is affinities in medium to high‐K calc‐alkaline suites, and has moderate rare earth elements (∑REE = 70.1–112.5 ppm) with flat REE patterns (LaN/YbN = 2.12–3.05) and exhibits enriched LILE, and Sr–Nd isotopes ((87Sr/86Sr)i = 0.713496–0.729216, εNd(t) = −2.93 to +2.04). Such typical "continental" geochemical features of the different K‐rich dykes do not result from crustal assimilation but reflect an enriched mantle source resulting from their mantle heterogeneity due to recycling of different subducted sediments. The temporal evolution of the geochemical characteristics of mafic‐intermediate dykes is consistent with an extension setting triggered by removing the thickened arc crust root in the WCQB. [ABSTRACT FROM AUTHOR]

The Shaolang River metallogenic belt in Inner Mongolia is one of the main lead‐zinc polymetallic belt on the northern margin of the North China Plate. The granodiorites, which are closely coexisting with lead‐zinc veins in deposit, are extensively developed. Previous geochronological research results show that the dikes and veins in the metallogenic belt belong to the products of magmatic hydrothermal activity in the middle Yanshanian, so the genesis of the metallogenic belt deposit is generally considered to be a hydrothermal vein type deposit related to sub‐volcanic dikes. We obtained zircon LA‐ICP‐MS U–Pb ages and Hf isotopic compositions of granodiorites, which are widely distributed in the deposit and were considered to be closely connected with the genesis of the deposits. The zircon U–Pb ages are 419.4 ± 1.4 Ma and 424.5 ± 4.1 Ma for the granodiorites, respectively, and they formed in the late Silurian. The geological and geochemical data indicate that the granodiorites are consistent with the geochemical characteristics of typical adakite. All εHf(t) values of the granodiorites are minus, on the zircon Hf isotope age diagram, εHf(t) are below the evolution curve of chondrite. The two‐stage model ages (tDM2) are 2.45 ~ 2.79 Ga and 1.87 ~ 2.29 Ga, respectively, showing rock‐forming materials mainly derived from the Paleoproterozoic and earlier crustal partial melting, and there may have been mantle‐derived magma underplating of the lower crust. Combining with the previous regional research, it is concluded that the granodiorites were formed during the extinction of the island arc under the background of subduction of the Paleo‐Asian Ocean and North China Craton. Because of the 125 ~ 170 Ma metallogenic age, we concluded that the granodiorites in the ore areas have no obvious relationship with the deposit genesis. However, it provided the advantageous space for the formation of the lead‐zinc veins, it can be regarded as an important prospecting indicator in metallogenic belt. [ABSTRACT FROM AUTHOR]

The northern Alxa area is the southernmost part of the central segment of the Central Asian Orogenic Belt and is located in a crucial junction to unravel the geological evolutionary history of the Palaeo‐Asian Ocean. Here, we present an integrated study of whole‐rock geochemistry, zircon U–Pb geochronology and zircon–Hf isotope on Early Permian igneous rocks from the Zhusileng–Hangwula Belt of the northern Alxa area. Three syenogranites, two monzogranites and one granodiorite are identified as peraluminous, (high‐potassium) calc‐alkaline I‐type granites. The zircon dating results show that they were formed during the Early Permian (291–285 Ma). Geochemically, these rocks show enrichments in light rare‐earth elements (LREEs), large‐ion lithophile elements (LILEs) and negative Nb–Ta anomalies, as well as low A/CNK values. Furthermore, the syenogranites have almost positive zircon εHf(t) values (−0.4 to +4.8) and Early Palaeoproterozoic–Mesoproterozoic Hf model ages (1,768–1,296 Ma), indicating that they were probably derived from juvenile crustal components, mixed with ancient continental crust. The monzogranites have markedly positive zircon εHf(t) values (+11.2 to +13.5) and Neoproterozoic–Cambrian Hf model ages (716–513 Ma), suggesting that they were generated by rapid reworking of newly formed juvenile material. The granodiorite shows positive zircon εHf(t) values (+4.0 to +7.0) and Mesoproterozoic Hf model ages (1,368–1,090 Ma), implying that the granodiorite was probably derived from the partial melting of the juvenile crust. Our geochronological, geochemical and isotopic data, combined with published data, unravel that a crustal thinning event that was simultaneous with more input of mantle materials in the northern Alxa area, implies that a subduction‐related extensional environment occurred in the Zhusileng–Hangwula Belt which is probably due to the slab rollback of the Paleo‐Asian Ocean during the Late Carboniferous–Early Permian. [ABSTRACT FROM AUTHOR]

In this study, textural relations coupled with mineral chemistry of hydrothermal magnetite, fluorapatite, monazite and allanite from the Mohuldih uranium deposit in the Singhbhum Shear Zone (SSZ) is used to characterize the nature of the fluid during various events of alteration and uranium precipitation. These minerals have two distinct textural types, the earlier of which are coeval with the uraninite mineralization. The later type formed during subsequent hydrothermal overprint as a result of coupled dissolution‐reprecipitation of earlier fluorapatite and mobilization of light rare earth elements. Uranium‐lead dating of texturally‐constrained hydrothermal monazite grains yields two major concordant age clusters at 1855 ± 7 Ma and 963 ± 10 Ma and several discordant analyses. Two spot analyses furnish concordant ages of 1656 ± 33 Ma and 1438 ± 35 Ma that are identical within error of the 207Pb/206Pb ages (1628–1643 Ma and ca. 1392 Ma) of several discordant data points. Similar ages have been reported by other studies from the rocks of the SSZ and are therefore considered to be geologically meaningful. The oldest age of ca. 1855 Ma obtained from the texturally early core regions of monazite corresponds to the earliest stage of uraninite mineralization. The two main alteration types can be interpreted based on the known metamorphic events in the SSZ. A combination of high‐temperature calcic iron ± sodic and high‐temperature potassic iron alteration accompanied the M1 metamorphic event and the low‐temperature silicification/K‐Al alteration during the M2 metamorphic event. A comparative study between our data on magnetite and fluorapatite compositions with those from global iron oxide‐Cu‐gold (IOCG) and iron oxide‐apatite deposits classifies Mohuldih as an IOCG‐type deposit. [ABSTRACT FROM AUTHOR]

Jurassic terrestrial sediments of the Jianggalesayi–Washixia Basin in the northwestern Altyn Tagh Orogen record abundant information regarding the evolution and uplift of the orogen. Investigation of this orogen is critical to establishing whether the Tarim and Qaidam basins were connected during the Jurassic. In this study, we present 474 single‐grain laser‐ablation–inductively coupled plasma–mass spectrometry detrital zircon U–Pb ages obtained from five Jurassic sandstone samples collected from four sections in the basin. Detrital zircons from the Lower Jurassic strata yield age populations of 997–726 and 551–509 Ma, indicating that the zircons were derived mainly from the southern–central Central Altyn Tagh Massif. Zircon age populations from the lower Middle Jurassic strata are 1024–838, 778–643, and 543–357 Ma, which suggest that the sediments were derived predominantly from the northern Central Altyn Tagh Massif and the southern South Altyn Tagh subduction–collision complex belt (SATSB). Zircon age populations from the upper Middle Jurassic strata are 980–830, 556–424, and 277–245, suggesting that these sediments were derived from the central SATSB. Detrital zircons from the Upper Jurassic strata display age groups of 515–387 and 325–226 Ma, indicating that these sediments originated from the northern SATSB. Uplift of the Altyn Tagh Orogen was initiated during the Middle to Late Triassic as a synchronous far‐field response to the collision of the Qiangtang Block with the Eurasian Plate. By the Early Jurassic, the Qaidam Basin was no longer connected with the Tarim Basin. During the Late Jurassic to Early Cretaceous, the collision of the Lhasa Block with the southern margin of the Eurasia Plate led to further uplift of the Altyn Tagh Orogen. [ABSTRACT FROM AUTHOR]

The Cenozoic Himalayan Orogeny is a manifestation of subduction and subsequent collision of the Indian lithosphere with the Asian Plate in the Eocene, resulting in the formation of intra‐terrane shear zones and regional metamorphic belt along the strike of the entire orogen. This metamorphic belt contains high‐pressure (HP) metamorphic rocks (garnet‐amphibolite, late‐stage granulite, and host gneisses) at various structural levels in the Himalayas. In the present study, we carried out geochemical, chronological, and metamorphic modelling of an exotic tschermakite‐bearing garnet‐amphibolite unit exposed within the Tethyan Himalayan Sequence of Western Garhwal Himalaya of India. Bulk‐rock geochemistry suggests the protolith's tholeiitic fractionation trend and trachy‐andesitic nature. U–Pb geochronology of zircon reveals an age spectrum with pronounced clusters at ~1,550 Ma, ~1,350 Ma, 1,100–1,150 Ma, 900–930 Ma, and ~550 Ma. There is a possibility that the protolith of the HP garnet amphibolite is magmatic. However, near‐concordant ages at certain intervals might suggest crustal components from multiple sources. Integrated geothermobarometry and P–T pseudosection modelling indicate high‐P/medium‐T conditions (~1.65 GPa and 650°C) of peak metamorphism. Based on these results, we infer that this garnet‐amphibolite represents pre‐Himalayan Indian lower crust and during India–Asia collision. The leading edge of the Indian continental lithosphere subducted where mafic and some of the felsic lithologies underwent HP garnet‐amphibolite facies metamorphism, and after a possible slab break‐off, these rocks exhumed during the Himalayan orogeny. [ABSTRACT FROM AUTHOR]

To date, the evolutionary history of the Proto‐Tethys Ocean that separated the Gondwana and Laurasia continents remains ambiguous. The Changning‐Menglian Suture Zone assumingly represents the Proto‐ and Palaeo‐Tethys suture in the Sanjiang area (the Yunnan Province, southwestern China). The Palaeozoic Proto‐Tethys Ocean in the Manxin area in the southmost Changning‐Menglian Suture Zone is widely recognized, but the timing and formation mechanism of the Manxin ophiolitic mélange are poorly understood. In this study, we present petrographical, geochronological and geochemical data of the Manxin ophiolitic mélange situated in the Changning‐Menglian Suture Zone. We found that this ophiolitic mélange is composed of pillow basalt, metamorphic gabbro, diabase dike, and altered peridotite. The mafic rocks could be divided into two groups based on geochemical characteristics: (1) Mid‐ocean ridge basalt (MORB) [formed at 446.0 ± 3.2 Ma and exhibiting depleted light rare earth element (LREE) patterns and high ƐNd(t) (+5.7 to +8.4)] Trace element and isotope analyses indicated that the MORB was derived from a spinel‐facies depleted mantle. (2) Ocean island basalt (OIB) [crystallized at 460.2 ± 6.0 Ma]. ƐNd(t) (+5.7) and significant enrichments in large‐ion lithophile element (LILE) and light rare earth element (LREE) were identified, while the trace element and isotope systematics suggested that the OIB rocks originated from partial melting of the garnet‐spinel lherzolite mantle. Overall, we clearly constrained the timing and nature of the Manxin ophiolitic mélange using the proposed data, thus further supporting the notion that the Manxin ophiolites represent remnants of the Proto‐Tethys Ocean. [ABSTRACT FROM AUTHOR]

The Bayan Obo–Duolun–Chifeng–Kaiyuan (BDCK) Fault is considered the boundary between the North China Craton (NCC) and Central Asian Orogenic Belt (CAOB). However, the site of this boundary from Duolun to Chifeng and Kaiyuan remains highly controversial. Here, we present an integrated study of petrology, whole‐rock geochemistry, and zircon U–Pb and Sr–Nd–Hf isotope compositions for tonalites and amphibolites in the Bainaimiao arc belt (BAB) to better constrain the northern NCC margin. The tonalites are similar to NCC tonalite–trondhjemite–granodiorites (TTGs), characterized by relatively high Na2O/K2O and Sr/Y ratios and fractionated rare earth element (REE) patterns, with high light REE (LREE) but low heavy REE (HREE) concentrations. Laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) zircon U–Pb dating yields formation ages of 2599–2674 Ma, with a weighted average of 2649.6 ± 3.7 Ma. The εHf(t) values (3.5–7.5), two‐stage model ages (2673–2793 Ma), whole‐rock positive εNd(t) values (1.3–1.9), and two‐stage model ages (2841–2880 Ma) suggest that the Neoarchean tonalites likely originated from remelting of thickened Meso‐Neoarchean mafic crust. LA–ICP–MS U–Pb isotope data reveal that the amphibolites formed at ~2610 Ma. They have high‐Fe tholeiitic compositions and are close to normal mid‐ocean ridge basalt (N‐MORB)‐like rocks, indicating that they were generated from partial melting of the depleted mantle. The existence of Neoarchean basement rocks, combined with seismic and isotope data, suggests that the Jiefangyingzi area is part of the Trans‐North China Orogen (TNCO) in the NCC rather than part of the CAOB and that the northern boundary of the NCC in Chifeng is located north to the Jiefangyingzi area. [ABSTRACT FROM AUTHOR]

East Junggar is an important part of the Central Asia Orogenic Belt and has developed a multi‐epoch and multi‐type metallogenic system. Yundukala is a recently discovered large intrusion‐related Au–Cu–Co deposit. The No. 1 main mineralization zone mainly occurs in the contact area between fine‐grained diorite and basalt. Massive and vein mineralization have developed there, but the ore‐bearing stratum, ore‐bearing intrusive rocks, and metallogenic ages are not clear. Zircon SHRIMP U–Pb dating of the porphyritic diorite and fine‐grained diorite yields ages of 416.1 ± 3.9 Ma and 411.1 ± 7.5 Ma, respectively. The dioritoid intruded into the ore‐bearing stratum, indicating that this formation is part of the Early Palaeozoic strata rather than the Middle Devonian Beishan Formation. The Re–Os isochron age of the chalcopyrite in the massive mineralization is 402.6 ± 5.2 Ma; thus, the massive mineralization is related to fine‐grained diorite and formed in the Early Devonian. Six sulphides and four sulphides from the vein mineralization yield Re–Os isochron ages of 352.8 ± 1.8 Ma and 354 ± 23 Ma, respectively, and the limited vein mineralization was formed during 353–354 Ma. The massive and vein mineralizations in the Yundukala deposit were formed in the Early Devonian and Early Carboniferous. [ABSTRACT FROM AUTHOR]

The along‐strike heterogeneity in the tectonics of Himalaya is well recognized; however, the eastern segment of Himalaya is less studied compared to the other segments. This study combines the comprehensive field data, as well as the U–Pb geochronology of sandstone samples from the Indo‐Burma Range (east India). The study shows that the Lower Disang Formation was deposited in an open marine environment with a steep gradient during the Late Cretaceous to Mid‐Eocene, accommodating the detritus solely from an Indian source. Furthermore, during the Early to Late Eocene interval, the sedimentary basin changed to a shallow marine shelf when the sediments from Himalayan as well as trans‐Himalaya were deposited. The Upper Disang Formation must have been deposited just before or during the collision process between the Indian and Asian plates. After the India‐Asian collision, there was a remnant ocean, in which the sediments of the Barail and Surma groups were deposited in the shallow marine to deltaic environments. The Tethys Ocean completely dried out in the Late Miocene resulting in a change from marine to fluvial environments, which facilitated the deposition of the sandstones of the Tipam Formation. Based on the U–Pb ages, the Palaeogene basin history in the Indo‐Burma Range was unlike the central Himalaya, that is, the detritus were mainly sourced from the Burmese Plate and adjoining magmatic rocks. [ABSTRACT FROM AUTHOR]

Source‐to‐sink system studies in oil fields are especially important for optimizing the favourable oil‐gas areas; however, this basin‐mountain interaction process is particularly complicated in intermontane basins. In this study, detrital zircon U–Pb dating of 8 new and 3 published samples from throughout the Jurassic in the central Turpan Basin (TB) are combined with collected heavy mineral data to investigate the evolution of the source‐to‐sink system and reconstruct the filling process of this intermontane basin from the Lower to Upper Jurassic. Based on the detrital zircon ages and heavy mineral assemblage, the filling rocks mainly weathered from Mesozoic, Palaeozoic and Precambrian volcanic and metamorphic rocks in the Tian Shan (TS) area, and the source‐to‐sink systems in the basin show a clear alteration corresponding to the uplift of the surrounding mountains during the Jurassic. In the Lower Jurassic, the uplifted central and northern TS was the main provenance and shed the most source rocks northward, and the gentle positive relief of the Bogda Mountains (BM), the northern boundary of the TB, was a secondary provenance and provided limited material to the northern area. In the early Middle Jurassic, these provenances did not alter much, but in the later Middle Jurassic, uplift of the western BM began and provided some extreme new source rocks with detrital zircon ages of approximately 159–172 Ma. In the Upper Jurassic, the considerably uplifted BM became the main provenance, while the still gently uplifted central and northern TS became the secondary provenance. [ABSTRACT FROM AUTHOR]