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We present new zircon U–Pb ages, geochemical data on the Late Palaeozoic volcanic rocks of the Suji and Dahongshan formations, which are exposed in the Plate Marginal Orogenic Belt along the northern margin of the North China Craton. Our aim is to constrain the petrogenesis, tectonic setting of volcanic rocks, and to address the late stage tectonic evolution of the Paleo‐Asian Ocean. Lithologically, the Suji and Dahongshan formations present the main rock association with basaltic andesite, andesite, dacite, rhyolite, and tuff. New zircon U–Pb dating results suggest that the volcanic rocks formed during 280–261 Ma and 277–267 Ma, respectively. Geochemically, these volcanic rocks belong to the low‐K tholeiitic to high‐K calc‐alkaline series and are characterized by highly enriched light rare earth elements, K, Rb, Ba; depleted Nb, Ta, Ti; and highly negative Eu anomalies, very similar to that of the continental arc magmatism. These data, together with geological field investigations, suggest that the Early Permian volcanic rocks from Suji and Dahongshan formations were related to southward flat subduction of the Paleo‐Asian Ocean beneath the northern margin of the North China Craton. Therefore, these volcanic rocks were interpreted as Andean‐style continental margin arc magmatism. This also indicates that the final collision between the North China Craton and the Siberian Craton did not occur until the Early Permian. [ABSTRACT FROM AUTHOR]

The Zhunmubutai ophiolitic mélange is a newly discovered ophiolite suite located between the Solonker‐Linxi ophiolite belt and the Erenhot‐Hegenshan‐Xi‐Ujimqin ophiolite belt, the central part of Xilinhot Microcontinent (XLMC). It was composed of plagiogranite, pyroxene peridotite, pillow basaltic andesite, and associated mafic rocks and surrounded by a quartz diorite pluton and mélange zone containing sandstones and slates of Early Permian Shoushangou Formation. In this study, zircon grains from a quartz diorite and a plagiogranite yield 206Pb/238U ages of 313 ± 1 Ma (MSWD = 1.60, n = 20) and 328 ± 1 Ma (MSWD = 0.9, n = 93), respectively. Sixty‐four zircons from the slate yielded ages ranging from 307 to 2,313 Ma, and with a peak at 340 Ma. These data indicate the Zhunmubutai ophiolitic mélange formed 300 to 340 Ma. The Zhunmubutai plagiogranites that have low contents of K2O (0.07–0.33 wt.%), K2O/Na2O (0.02–0.09), and Rb/Sr (0.01–0.05) show an oceanic plagiogranites affinity. They are also characterized by low contents of TiO2, Nd, Ta, and significant LREE enrichment. Furthermore, the εHf (328 Ma) values range from 14.23 to 18.87. These features suggest that the plagiogranite was originated by the anatexis of amphibolites and with crustal contamination. Combined with previous studies, suggest that the Zhunmubutai ophiolitic mélange may have formed in an extensional environment during the early stages of opening of an ocean basin. [ABSTRACT FROM AUTHOR]

The sedimentary record in the Late Palaeoproterozoic‐Neoproterozoic Bayan Obo rift belt can provide critical insight into tectonic evolution of Columbia and the North China Craton. In this study, we present new U–Pb geochronology, Hf isotopic analyses from the Bayan Obo Group, the Mesoproterozoic kimberlite, and gabbro to constrain the depositional age and potential provenance information of the Bayan Obo Group. We show that the Dulahala‐Jianshan, Bilute, and Baiyinbaolage formations were deposited at ca. 1.81–1.7 Ga, ca. 1.58–1.35 Ga, and ca. 1.25–1.0 Ga, respectively. Our data suggest the following potential provenance for sediments within the Bayan Obo Group: (a) The Khondalite Belt, Yinshan Block, and crystalline basement complex of the North China Craton to the south were the most potential provenance of the Dulahala and Jianshan formations during the initial deposition of Bayan Obo Group; (b) The Yinshan Block, and crystalline basement complex of the North China Craton, and local intermediate‐acid igneous rocks were the most potential provenance of the Bilute Formation; and (c) the local gabbro and volcanic rocks were the most potential provenance of the Baiyinbaolage Formation. Based on regional geologic constraints and the sedimentary history, we propose that the Northern Marginal Rift System probably represented several distinct rifting events. Furthermore, the Bayan Obo and Huade rift belts were active more recently than 1.0 Ga, which suggests that these rift systems were not only related to the rifting of the Columbia supercontinent. We propose that the Bayan Obo rift belt also records the rifting related to the breakup of Rodinia with the deposition of Qingbaikou System (Tonian) strata. [ABSTRACT FROM AUTHOR]

Zircon U–Pb dating and whole‐rock geochemical analysis have been studied on the Late Jurassic volcanic rocks in the Hailisen area, Northeastern China, with the aim of constraining the tectonic evolution of the central‐southern Great Xing'an Range during the Late Jurassic. The volcanic rocks mainly consist of andesite from the Tamulangou Formation, and rhyolite and minor dacite from the Manketouebo Formation. The results of inductively coupled plasma‐mass spectrometry Zircon U–Pb dating for two andesites and one dacite indicate that they formed in the Late Jurassic (161–150 Ma). The mafic rocks are characteristic of low TiO2 (1.01–1.04 wt.%) and P2O5 (0.23–0.31 wt.%) contents, and high Al2O3 (17.19–20.18 wt.%) and CaO (6.69–7.45 wt.%) contents, and belong to the low‐K tholeiitic series. These mafic rocks are also characterized by moderately enriched light rare earth element (LREE) patterns and high abundances of Th, U, Zr, and Hf but negative Nb, Ta, and Ti anomalies. The felsic rocks are enriched in alkalis, Th, U, and LREEs; depleted in Ba, Sr, Nb, Ta, and Ti; and exhibit moderately LREE‐enriched patterns. These features indicate that the mafic volcanic rocks were likely formed by the partial melting of a lithospheric mantle that was metasomatized by subduction‐derived components, but the felsic rocks could derived by partial melting of a crustal source. The Tamulangou and Manketouebo formations have compositions of typical bimodal volcanism, an extensional environment, similar to a post‐orogenic setting, which might be related to the closure of Mongol–Okhotsk Ocean. [ABSTRACT FROM AUTHOR]

Porphyritic olivine kimberlitic breccia, discovered in the Dörbed Banner of Inner Mongolia, Western China, is referred to as Longtou Shan Kimberlite in our study. This kimberlite occurs as a pipe in the Halahuogete Formation of Bayan Obo Group. Zircon U–Pb ages of Longtou Shan Kimberlite reveals a Mesoproterozoic age of ~1,552 Ma, constraining the deposition age of Halahuogete Formation to the Mesoproterozoic. Compared with Mesoproterozoic kimberlite of the ancient landmass, it can be inferred that the North China Craton is a member of the Ur ancient continent of the Columbia supercontinent. Furthermore, according to the tectonic background of the Bayan Obo Group, we raise this possibility that “Bayan Obo Aulacogen” should be renamed the “Bayan Obo Continental Rift.” [ABSTRACT FROM AUTHOR]

We conducted zircon U–Pb dating and geochemical analyses for the Qianjinchang (QJC) pluton in the Xi Ujimqi, Northeast China, with an aim to determine their ages, petrogenesis, and sources. The QJC pluton consists of coarse/medium‐grained biotite monzogranite in the core and fine‐grained biotite granodiorite in the rim; those rocks intrude into quartz diorite but are intruded by minor intrusive phases, including small biotite syenogranite, diorite bodies, late diorite, granodiorite, granite, and pegmatite dykes. Our new laser ablation inductively coupled plasma mass spectrometry zircon U–Pb data indicate that the QJC composite pluton composed of 2 phases of magmatic activities, with the ages of 301~313 Ma for the quartz diorite, 283 ± 1 Ma for the biotite granodiorite, 280 ± 1 Ma for the biotite syenogranite, and 280 ± 2 Ma for the diorite dyke. Hf isotopic analyses for the quartz diorite sample show εHf (t) = 3.75 to 11.72, with 2‐stage Hf model age (TDM2) ranging 568–1,078 Ma. The biotite syenogranite sample also shows a depleted εHf (t) = 4.47 to 8.71, with TDM2 ranging 745–1,015 Ma, suggesting the major involvement of juvenile crustal components. The various εHf values of the QJC pluton indicate a hybrid magma source of juvenile material with old crustal component, and the TDM2 values increase from the Carboniferous to Permian, which suggests an increasing proportion of old continental material during this period. Petrological and geochemical characteristics of the biotite granodiorite and biotite monzogranite samples suggest that they are S‐type granites and derived from partial melting of the clay‐poor, plagioclase‐rich psammitic source, produced at low‐medium pressure. The biotite syenogranite sample belongs to alkaline and shoshonitic series and probably formed by a hybridization process between basaltic magma and old continental components. Combined with previous studies on the contemporaneous magma‐tectonic activities in the Xilinhot microcontinent, we suggest that the QJC pluton formed in a postcollisional setting. [ABSTRACT FROM AUTHOR]

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

Subduction of Bangong Suture Ocean and collision between the Lhasa and Qiangtang blocks were keys to better understand the development of central Tibet. However, the initiation and closure timing, and nature and structure of the Bangong suture are still poorly constrained. Mesozoic intrusions are widely distributed in central Tibet. Petrology, geochronology and geochemistry of the Renacuo pluton and their microgranular enclaves in the Gaize area to the north of the Bangong-Nujiang suture zone, south of the Longmu Co-Shuanghu suture zone, are used to constrain the tectonic history of the Bangong suture. Results of our SHRIMP U-Pb dating of the zircons are as follows: quartz diorite is 139 ± 4 Ma, MSWD = 1.6; the microgranular enclave is 147.3 ± 3.3 Ma, MSWD = 0.45. The evolutionary trend of the major elements, trace elements and rare earth elements of the microgranular enclaves and the host rocks are almost similar, suggesting that the enclaves and the host rocks may have had the same source. They most likely originated from magma mixing between mantle-derived and crust-derived melts. On the basis of our mapping and geochronologic studies, we suggest that the formation of the Renacuo pluton is consistent with previously suggested northward subduction of the Bangong Suture Ocean, which occurred in the Late Jurassic-Early Cretaceous. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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