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Geochemical research into origins of two types of Mesozoic rhyolites in Daxing'anling

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... Basins) (Meng et al. 2003;Ji et al. 2019a, b). Nevertheless, the specific geodynamic processes that led to the extensional tectonic setting remain contentious, with the various schemes proposed including (1) upwelling of a mantle plume (Lin et al. 1998;Ge et al. 2000); (2) gravitational collapse of orogenically thickened crust after closure of the Mongol-Okhotsk Ocean (MOO) Meng et al. 2003;Xu et al. 2008;Ying et al. 2010;Guan et al. 2018); (3) large-scale lithospheric delamination related to subduction of the Palaeo-Pacific Plate (Wu et al. , 2011Zhang et al. 2010;Li et al. 2019;Suo et al. 2019); and (4) rollback of the subducted Palaeo-Pacific flat slab and subsequent upwelling of asthenospheric mantle (Ji et al. 2019a, b). However, regardless of the particular geodynamic processes that were involved, intense crust-mantle interactions and vertical accretion of continental crust are expected to have occurred in the GXR during the Early Cretaceous Epoch, as indicated by the upwelling of asthenospheric-mantle materials to various degrees. ...
... Crust-mantle interaction within the GXR has so far been poorly constrained, as previous studies were based mainly on geochemical and geochronological data on either the widespread crust-derived felsic rocks or individual mantle-derived mafic-intermediate igneous outcrops (Ge et al. 2000;Fan et al. 2003;Zhang et al. 2008aZhang et al. , 2010Gou et al. 2010Gou et al. , 2013Wu et al. 2011;Dong et al. 2014;Ji et al. 2016Ji et al. , 2018. In this context, exploration of the processes and mechanisms of crust-mantle interaction is required by simultaneously studying both the mantle-and crust-derived rock associations in the same volcanic formation, the results of which should also provide insights into the Early Cretaceous geodynamic setting of the GXR. ...
... (mean of 29.79), which are closer to the ratios of crust (11.4 and 33, respectively;Taylor & McLennan, 1985) than to those of primitive mantle (17.8 and 37.0, respectively; Sun & McDonough, 1989). The rhyolites are enriched in Rb and K, but depleted in Ba, Sr and Ti, which is consistent with the characteristics of low Ba-Sr volcanic rocks classified by Ge et al. (2000) and Zhang et al. (2010). Combining this information with their depletion in HFSEs and high K 2 O/Na 2 O ratios suggests that the rhyolite samples might have originated from the partial melting of continental crust rather than oceanic crust (Chappell & White, 1992;Beate et al. 2001). ...
Article
Late Mesozoic igneous rocks are important for deciphering the Mesozoic tectonic setting of NE China. In this paper, we present whole-rock geochemical data, zircon U–Pb ages and Lu–Hf isotope data for Early Cretaceous volcanic rocks from the Tulihe area of the northern Great Xing’an Range (GXR), with the aim of evaluating the petrogenesis and genetic relationships of these rocks, inferring crust–mantle interactions and better constraining extension-related geodynamic processes in the GXR. Zircon U–Pb ages indicate that the rhyolites and trachytic volcanic rocks formed during late Early Cretaceous time ( c. 130–126 Ma). Geochemically, the highly fractionated I-type rhyolites exhibit high-K calc-alkaline, metaluminous to weakly peraluminous characteristics. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) but depleted in high-field-strength elements (HFSEs), with their magmatic zircons ϵ Hf ( t ) values ranging from +4.1 to +9.0. These features suggest that the rhyolites were derived from the partial melting of a dominantly juvenile, K-rich basaltic lower crust. The trachytic volcanic rocks are high-K calc-alkaline series and exhibit metaluminous characteristics. They have a wide range of zircon ϵ Hf ( t ) values (−17.8 to +12.9), indicating that these trachytic volcanic rocks originated from a dominantly lithospheric-mantle source with the involvement of asthenospheric mantle materials, and subsequently underwent extensive assimilation and fractional crystallization processes. Combining our results and the spatiotemporal migration of the late Early Cretaceous magmatic events, we propose that intense Early Cretaceous crust–mantle interaction took place within the northern GXR, and possibly the whole of NE China, and that it was related to the upwelling of asthenospheric mantle induced by rollback of the Palaeo-Pacific flat-subducting slab.
... In northeast China, the volcanic rocks cover an area of approximately 100,000 km 2 , including the Great Xing'an Range and the Erlian Basin (Figure 1(a)), and make up a major portion of the Mesozoic stratigraphy (IMBGMR 1991). Many studies have focused on late Mesozoic volcanic rocks that are distributed in northeast China (Ge et al. , 2000Guo et al. 2001;Fan et al. 2003;Wang et al. 2006;Zhang et al. 2008aZhang et al. , 2010Xu et al. 2008Xu et al. , 2013aLi et al. 2017aSun et al. 2017;He et al. 2018;Gong et al. 2018;Tang et al. 2018). Different models have been proposed for the history of the massive volcanic rocks. ...
... Different models have been proposed for the history of the massive volcanic rocks. Lin et al. (1998Lin et al. ( , 1999Lin et al. ( , 2004 and Ge et al. (1999Ge et al. ( , 2000 proposed a mantle plume model to explain extensive late Mesozoic magmatism in northeast Asia. Shao et al. (1994) and Fan et al. (2003) suggested that the late Mesozoic volcanic rocks originated in a Basin and Range-type tectonic environment that resulted from the closure of the Mongol-Okhotsk Ocean. ...
... The increase of mantle components could result in the felsic rocks transform from A 1 to A 2 type in evolution of the rocks with A type granites affinities (Roberts 1993;Chen et al. 2008;Zhou et al. 2010;Azizi et al. 2017 Figure 11(c), suggesting the extension setting could be related to post-collision. Three tectonic models for the Early Cretaceous volcanic rocks in northeast China have been proposed as follows: (1) post-orogenic gravitational collapse and subsequent extension related to the closure of the Mongol-Okhotsk Ocean (Guo et al. 2001;Fan et al. 2003;Meng 2003;Zhang et al. 2007;Ying et al. 2010;Wang et al. 2013); (2) subduction of the Palaeo-Pacific Plate followed by lithospheric delamination and asthenosphere upwelling (Wang et al. 2006;Zhang et al. 2008aZhang et al. , 2010Dong et al. 2014); and (3) mantle plumerelated intraplate extension (Lin et al. 1998Ge et al. 1999Ge et al. , 2000Deng et al. 2004). ...
Article
Early Cretaceous volcanic rocks are widely distributed in northeast China and being extensively observed recently. However, petrogenesis and tectonic setting of these volcanic rocks are still on debate. We present zircon U–Pb ages, whole-rock geochemistry and zircon Hf isotope for these volcanic and sub-volcanic rocks surrounding the Erlian Basin including basic-intermediate volcanic rocks, intermediate-felsic volcanic rocks, and dacites and trachyandesite from dikes. The zircon U–Pb dating results indicate that these rocks formed in the Early Cretaceous (146–129 Ma). The basic-intermediate volcanic rocks mainly consist of basaltic andesite, which are featured by low SiO2 concentrations (49.96–58.34 wt. %), high Mg# values (54–37) and Co contents (17.85–25.98 ppm), and positive εHf(t) values (+7.11 to +13.87). Moreover, they show high La/Nb (1.79–2.87) and low La/Ba (0.02–0.08) ratios. Such features indicate that they were derived from partial melting of lithospheric mantle that had been modified by fluids. The intermediate-felsic volcanic rocks consist of trachydacite and andesite, which show medium SiO2 concentrations (58.31–66.44 wt. %), a wide range of Mg# values (28–53) and with A1-type granites affinities. These features, along with slightly positive to negative εHf(t) values (+0.53 to −17.71), indicate that they originated from mixed magma of melted lower crust and mantle substances. Dacites from dikes are distinguished by high SiO2 concentrations (65.72–67.2 wt. %), negative εHf(t) values (−2.55 to −6.72) and old zircon Hf TDM2 ages (1453–1653 Ma), suggesting they were generated by melting of Mesoproterozoic and Palaeoproterozoic crustal material. All of the investigated volcanic and sub-volcanic rocks exhibit geochemical signatures of extension setting. In combination with previous studies, we suggest the Early Cretaceous extension in northeast China is related to the collapse of thickened lithosphere after closure of the Mongol–Okhotsk Ocean and to the slab break off of the Mudanjiang Ocean.
... During the past decades, numerous studies have been conducted on these rocks (e.g. Jiang and Quan, 1988;Zhao et al., 1989;Ge et al., 2000Ge et al., , 2001Lin et al., 2000Lin et al., , 2003Shao et al., 2001a,b;Guo et al., 2001;Fan et al., 2003;Gao et al., 2005;Zhang et al., 2006). However, there has been much debate concerning the tectonic setting in which these rocks formed and several proposals have been put forward to explain the driving force for this magmatism, for example: ...
... In the TAS (SiO 2 -Na 2 O + K 2 O) classification diagram ( Fig. 3), these volcanic rocks straddle the alkalinesubalkaline boundary and plot as basalt, basaltic-andesite, andesite, dacite, rhyolite, trachy-andesite, as well as trachyte and more alkaline types. Geochemically (Jiang and Quan, 1988;Zhao et al., 1989;Ge et al., 2000Ge et al., , 2001Lin et al., 2000Lin et al., , 2003Shao et al., 2001a,b;Guo et al., 2001;Fan et al., 2003;Gao et al., 2005;Zhang et al., 2006), the volcanic rocks possess similar rare earth element (REE) patterns, but with variable amounts of HREE depletion and variable negative Eu anomalies. The trace element patterns show a relatively strong depletion of Nb, Ta, P and Ti, and a wide range in Rb, Ba and Sr values. ...
... Irvine and Baragar (1971). Data sources: Jiang and Quan (1988), IMBGMR (1991), HBGMR (1993), Ge et al. (1999Ge et al. ( , 2000Ge et al. ( , 2001; Lin et al. (2000Lin et al. ( , 2003. ...
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The Great Xing'an Range in northeastern China is characterized by large-scale Mesozoic magmatism, and forms a key part of the NE-trending Mesozoic magmatic belt in East China. However, only limited precise age data for the volcanic rocks in this belt were previously available, which significantly hampers understanding of the petrogenesis and geodynamic setting of these rocks. Systematic dating of volcanic rocks in the Great Xing'an Range was undertaken in order to rectify this situation. The Mesozoic volcanic rocks in the area have been sub-divided into the Tamulangou, Shangkuli and Yilieke formations. The Tamulangou and Yiliekede formations are composed of basalt and basaltic andesite, whereas the Shangkuli Formation consists of rhyolite and dacite. Zircon U–Pb and whole rock 40Ar/39Ar dating, combined with published data, indicate that the Tamulangou Formation was formed over a large time interval from the Early Jurassic to Early Cretaceous; it should therefore not be regarded as a single stratigraphic unit. In contrast, volcanic rocks of the Shangkuli and Yiliekede formations were erupted in the Early Cretaceous, between 125–115 Ma. Overall, most Mesozoic volcanic rocks in the Great Xing'an Range were erupted during the Early Cretaceous with an age peak at ∼ 125 Ma, coeval with the time of lithospheric thinning in the eastern part of the North China Craton. Therefore, the Great Xing'an Range constitutes an important area that records a significant Early Cretaceous giant igneous event in eastern China. It is possible that this activity was related to subduction of the Pacific plate during the Late Mesozoic, as has been suggested to explain crustal thinning of the North China Craton.
... These data indicate that most of the Mesozoic volcanic rocks in the Da Xing'anling region formed during the Early Cretaceous [10,11], with most of the volcanic rocks consisting of calc-alkaline and alkaline types in southern and northern Da Xing'anling, respectively. Both derived from an enriched mantle [12]. Acidic volcanic rocks are divided into high Sr rhyolite and low Sr rhyolite types; high Sr rhyolite types were formed by the differentiation of calc-alkaline basaltic magma, and low Sr rhyolite types were produced by the partial melting of lower crustal rocks [13]. ...
... This tectonic background is closely related to the evolution of the Mongol-Okhotsk Ocean. This interpretation is consistent with the tectonic context displayed by the bimodal volcanic rocks at Tamurangou (160-164 Ma) and Manketourbo (159-162 Ma), as well as the A1 rhyolite of the Baiyingaolao Formation (139-142 Ma) [12,13,50]. This is broadly consistent with the timing of the formation of mafic volcanic rocks in the study region. ...
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The northwestern Erguna Block, where a wide range of volcanic rocks are present, provides one of the foremost locations to investigate Mesozoic Paleo-Pacific and Mongol-Okhotsk subduction. The identification and study of Late Jurassic mafic volcanic rocks in the Badaguan area of northwestern Erguna is of particular significance for the investigation of volcanic magma sources and their compositional evolution. Detailed petrological, geochemical, and zircon U-Pb dating suggests that the Late Jurassic mafic volcanic rocks formed at 157–161 Ma. Furthermore, the geochemical signatures of these mafic volcanic rocks indicate that they are calc-alkaline or transitional series with weak peraluminous characteristics. The rocks have a strong MgO, Al2O3, and total alkali content, and a SiO2 content of 53.55–63.68 wt %; they are enriched in Rb, Th, U, K, and light rare-earth elements (LREE), and depleted in high-field-strength elements (HFSE), similar to igneous rocks in subduction zones. These characteristics indicate that the Late Jurassic mafic volcanic rocks in the Badaguan area may be derived from the partial melting of the lithospheric mantle as it was metasomatized by subduction-related fluid and the possible incorporation of some subducting sediments. Subsequently, the fractional crystallization of Fe and Ti oxides occurred during magmatic evolution. Combined with the regional geological data, it is inferred that the studied mafic volcanic rocks were formed by lithospheric extension after the closure of the Mongol-Okhotsk Ocean.
... [121,122]. Other data are from [22,53,70,71,75]. ...
... (D) The chondrite-normalized rare earth element (REE) pattern of the andesite porphyry. Other data are quoted from the literature[22,53,70,71,75]. ...
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Late Mesozoic intermediate–felsic volcanics and hypabyssal intrusions are common across the western slope of the Great Xing’an Range (GXAR). Spatiotemporally, these hypabyssal intrusions are closely associated with epithermal Pb–Zn polymetallic deposits. However, few studies have investigated the petrogenesis, contributions and constraints of these Pb–Zn polymetallic mineralization-related intrusions. Therefore, we examine the representative Erdaohezi deposit and show that these mineralization-related hypabyssal intrusions are composed of quartz porphyry and andesite porphyry with concordant zircon U–Pb ages of 160.3 ± 1.4 Ma and 133.9 ± 0.9 Ma, respectively. These intrusions are peraluminous and high-K calc-alkaline or shoshonitic with high Na2O + K2O contents, enrichment in large ion lithophile elements (LILEs; e.g., Rb, Th, and U), and depletion in high field strength elements (HFSEs; e.g., Nb, Ta, Zr, and Hf), similar to continental arc intrusions. The zircon εHf(t) values range from 3.1 to 8.0, and the 176Hf/177Hf values range from 0.282780 to 0.282886, with Hf-based Mesoproterozoic TDM2 ages. No differences exist in the Pb isotope ratios among the quartz porphyry, andesite porphyry and ore body sulfide minerals. Detailed elemental and isotopic data imply that the quartz porphyry originated from a mixture of lower crust and newly underplated basaltic crust, while the andesite porphyry formed from the partial melting of Mesoproterozoic lower crust with the minor input of mantle materials. Furthermore, a magmatic–hydrothermal origin is favored for the Pb–Zn polymetallic mineralization in the Erdaohezi deposit. Integrating new and published tectonic evolution data, we suggest that the polymetallic mineralization-related magmatism in the Erdaohezi deposit occurred in a back-arc extensional environment at ~133 Ma in response to the rollback of the Paleo-Pacific Plate.
... The generation of highly fractionated I-type granites could be associated with various tectonic environments including active continental margin and alternative post-collision extensional regime, as well as anorogenic setting (Wu et al., 2003;Li et al., 2007;Zhu et al., 2009). However, it is widely accepted that NE China was in an extensional environment during the Early Cretaceous, which is confirmed by the occurrence of metamorphic core complexes, extensional basins, bimodal volcanic rocks and A-type granites (Zhang et al., 1998Ge et al., 1999Ge et al., , 2000Ge et al., , 2001Shao et al., 2001;Wu et al., 2002;Meng, 2003;Fan et al., 2003;Gao et al., 2005;Tang et al., 2016;Li et al., 2018a). Over the last two decades, several geodynamic models have been proposed for the Late Mesozoic extension in NE China, including lithospheric extension after closure of Mongol-Okhotsk Ocean (Fan et al., 2003;Meng, 2003;Ying et al., 2010;Tang et al., 2016;Li et al., 2018a), lithospheric delamination or backarc extension associated with the subduction of Paleo-Pacific Ocean (Wu et al., , 2011Wang et al., 2006;Zhang et al., 2010aZhang et al., , 2011Sun et al., 2013a;Dong et al., 2014;Li et al., 2014Li et al., , 2015aBar et al., 2018), and upwelling of the mantle plume (Lin et al., 1998;Ge et al., 2000;Deng et al., 2004). ...
... However, it is widely accepted that NE China was in an extensional environment during the Early Cretaceous, which is confirmed by the occurrence of metamorphic core complexes, extensional basins, bimodal volcanic rocks and A-type granites (Zhang et al., 1998Ge et al., 1999Ge et al., , 2000Ge et al., , 2001Shao et al., 2001;Wu et al., 2002;Meng, 2003;Fan et al., 2003;Gao et al., 2005;Tang et al., 2016;Li et al., 2018a). Over the last two decades, several geodynamic models have been proposed for the Late Mesozoic extension in NE China, including lithospheric extension after closure of Mongol-Okhotsk Ocean (Fan et al., 2003;Meng, 2003;Ying et al., 2010;Tang et al., 2016;Li et al., 2018a), lithospheric delamination or backarc extension associated with the subduction of Paleo-Pacific Ocean (Wu et al., , 2011Wang et al., 2006;Zhang et al., 2010aZhang et al., , 2011Sun et al., 2013a;Dong et al., 2014;Li et al., 2014Li et al., , 2015aBar et al., 2018), and upwelling of the mantle plume (Lin et al., 1998;Ge et al., 2000;Deng et al., 2004). Combined with the temporalspatial distribution, the formation of Early Cretaceous granitoid in NE China is inconsistent with the characteristics of mantle plume model, which is related to rapid and short-lived magmatism and circular distribution. ...
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In this study, we present zircon U‐Pb ages, whole‐rock geochemical data and Hf isotopic compositions for the Meiguifeng and Arxan plutons in Xing'an Massif, Great Xing'an Range, which can provide important information in deciphering both Mesozoic magmatism and tectonic evolution of NE China. The zircon U‐Pb dating results indicate that alkali feldspar granite from Meiguifeng pluton was emplaced at ∼145 to 137 Ma, and granite porphyry of Arxan pluton was formed at ∼129 Ma. The Meiguifeng and Arxan plutons have similar geochemical features, which are characterized by high silica, total alkalis, differentiation index, with low P2O5, CaO, MgO, TFe2O3 contents. They belong to high‐K calc‐alkaline series, and show weakly peraluminous characteristics. The Meiguifeng and Arxan plutons are both enriched in LREEs and LILEs (e.g., Rb, Th, U and K), and depleted in HREEs and HFSEs (e.g., Nb, Ta and Ti). Combined with the petrological and geochemical features, the Meiguifeng and Arxan plutons show highly fractionated I‐type granite affinity. Moreover, the Meiguifeng and Arxan plutons may share a common or similar magma source, and they were probably generated by partial melting of Neoproterozoic high‐K basaltic crust. Meanwhile, plagioclase, K‐feldspar, biotite, apatite, monazite, allanite and Ti‐bearing phases fractionated from the magma during formation of Meiguifeng and Arxan plutons. Combined with spatial distribution and temporal evolution, we assume that the generation of Early Cretaceous Meiguifeng and Arxan plutons in Great Xing'an Range was closely related to the break‐off of Mudanjiang oceanic plate. Furthermore, the Mudanjiang Ocean was probably a branch of Paleo‐Pacific Ocean.
... Therefore, the complex effects of multiple plates and a protracted evolutionary history have resulted in the voluminous late Mesozoic magmatism of NE China with its various tectonomagmatic origins Wu et al., 2011;Xu et al., 2013;. This complexity has led to intensive debates on the origins and geodynamic settings of the magmatism, and the various schemes proposed include: (a) the upwelling of a mantle plume (Lin et al., 1998;Ge et al., 2000;Deng et al., 2004), (b) post-orogenic lithospheric extension following continental collision related to the closure of the Mongol-Okhotsk Ocean (Fan et al., 2003;Meng, 2003;Ying et al., 2010;T. Wang et al., 2015), (c) large-scale lithospheric delamination related to the subduction of the Paleo-Pacific Plate (Wu et al., 2005;F. ...
... In contrast to the well-studied Mesozoic volcanic rocks of the Great Xing'an Range (Lin et al., 1998;Ge et al., 2000;Fan et al., 2003;Zhang et al., 2006Zhang et al., , 2010J.H. Zhang et al., 2008;Zhang, 2014;Guo et al., 2009;Gou et al., 2010Gou et al., , 2013Ying et al., 2010;Li et al., 2014;Dong et al., 2014;Yang et al., 2015;Ji et al., 2016Ji et al., , 2018Gu et al., 2016;Bars et al., 2018), there have been few systematic investigations of the buried Cretaceous volcanic rocks within the Songliao Basin (P.J. Wang et al., 2006;Meng et al., 2010;Zhang et al., 2011;Li et al., 2015). P.J. Wang et al. (2006) proposed that the petrogenesis of the Cretaceous acidic volcanic rocks in the Songliao Basin was involved in the combined processes of crustal assimilation and fractional crystallization, and that the primary magmas of these acidic volcanic rocks originated from metasomatized enriched MORB-like sources in a post-collisional setting after closure of the Mongol-Okhotsk Ocean. ...
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There is a broad consensus that the extensive late Mesozoic igneous rocks in NE China were generated in an extensional setting. However, the timing and mechanism of the lithospheric extension remain controversial. To address this, we carried out an integrated study involving LA–ICP–MS zircon U–Pb dating and geochemical analyses (major elements, trace elements, and Hf isotopes) for the Early Cretaceous adakitic lavas and A-type rhyolites of the Songliao Basin. The adakitic lavas are andesites and dacites. The U–Pb dating of zircons from the adakitic lavas and A-type rhyolites yielded ages between 115 and 102 Ma. Geochemically, the adakitic lavas are characterized by high Sr contents (515–1610 ppm) and low Y (0.98–17.58 ppm) and heavy rare earth element (HREE) contents, and they therefore have high Sr/Y (51–112) ratios. They also exhibit high Mg# values (36–57) and high contents of MgO (0.56–3.53 wt%), Cr (15.7–87.3 ppm), and Ni (6.7–44.7 ppm) that are comparable with those of high-Mg adakitic rocks. The A-type rhyolites show an affinity with aluminous A-type magmatic rocks, and they are metaluminous to peraluminous (A/CNK = 0.98–1.35), enriched in alkalis, Ga, Zr, Nb, and Y, depleted in Sr and P, and exhibit fractionated REE patterns with negative Eu anomalies (Eu/Eu* = 0.05–0.77). All the primary zircons from the adakitic lavas and A-type rhyolites have positive εHf(t) values of +3.6 to +12.1 and juvenile two-stage model (TDM2) ages of 934–392 Ma. The adakitic lavas probably resulted from the partial melting of a delaminated region of the lower continental crust, with the magmas subsequently interacting with mantle materials upon ascent, while the A-type rhyolites were probably generated by the partial melting of a dehydrated charnockitic middle–lower crust. The data suggest that the adakitic lavas and the A-type rhyolites formed in an extensional environment related to the rollback of the subducting Paleo-Pacific Plate. The upwelling of asthenospheric mantle and local delamination of the lithosphere, which were induced by rollback of the subducting Paleo-Pacific Plate, extended from the Great Xing'an Range southeastward through the Songliao Basin to eastern Heilongjiang and Jilin provinces, giving rise to the southeastward migration of lithospheric extension and extension-related volcanism after ca. 140 Ma.
... The volcanic rocks in the northern Great Xing'an Range are dominated by alkaline series rocks, whereas the southern area is dominated by calc-alkaline series rocks . The acid volcanic rocks and sub-alkaline series basalt to andesite in the south-central part of the Great Xing'an Range are the products of magmatic differentiation (Ge, Lin, Sun, Wu, & Li, 2000;Lin et al., 2000;Lin, Ge, Cao, Sun, & Lin, 2003). The basic volcanic rocks and dacitic rocks reflect bimodal magmatism, and the rhyolite was formed by crustal contamination or partial melting of lower crust (Gao, Guo, Fan, Li, & Li, 2005;Guo, Fan, Wang, & Lin, 2001). ...
... The formation of the Great Xing'an Range was related to both the Paleo-Asia and Pacific tectonic regimes and the geochemical processes of the deep mantle. One of the most important factors controlling the formation of these Mesozoic volcanic rocks was the deep subduction of the cold Paleo-Asia Plate, which caused the rise of the mantle plume Lin et al., 1998;Ge et al., 1999Ge et al., , 2000. ...
Article
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.
... Zheng et al. 2007;Wang et al. 2011;Dong et al. 2014). Several genetic models have been proposed for this volcanism, including mantle plume activity (Lin et al. 1998;Ge et al. 1999Ge et al. , 2000, subduction of the Mongol-Okhotsk Ocean crust (Fan et al. 2003;Meng 2003;Wang et al. 2015), post-orogenic extension after closure of the Mongol-Okhotsk Ocean (Ying et al. 2010;Mei et al. 2014), subduction of the Palaeo-Pacific Plate (Zhao et al. 1989;Wu et al. 2005;Wang, Zhou et al., 2006;Zhang et al. 2008Zhang et al. , 2010Dong et al. 2014), and the influence of the Mongol-Okhotsk Ocean and circum-Pacific Ocean tectonic regimes (Xu et al. 2013a;2013b;Meng et al. 2014;Yang et al. 2015). However, the tectonic setting of these volcanic rocks remains controversial, primarily as the spatial and temporal extents of the circum-Pacific and Mongol-Okhotsk tectonic regimes remain unclear (Xu et al. 2013a;Meng et al. 2014). ...
... average of 30.33) ratios that are consistent with crustal values (Taylor and McLennan 1985;Tischendorf and Paelchen 1985). The petrology of these units and the significant depletions in Ba, Sr, Eu, P, and Ti indicate they are similar to the type-II rhyolites (with strong negative Ba anomaly; Ge et al. 2000) in the GXR, suggesting that they derived from magmas generated by the partial melting of mafic lower crust. Finally, the ε Hf (t) values (+5.00 to +8.93) and T DM2 ages (870-652 Ma) of zircons within these units (Figure 9(a,b)) suggest that they formed from a primary magma generated by the partial melting of crustal material accreted during the Neoproterozoic. ...
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This study presents new zircon U–Pb geochronology, geochemistry, and zircon Hf isotopic data of volcanic and subvolcanic rocks that crop out in the Bayanhushuo area of the southern Great Xing’an Range (GXR) of NE China. These data provide insights into the tectonic evolution of this area during the late Mesozoic and constrain the evolution of the Mongol–Okhotsk Ocean. Combining these new ages with previously published data suggests that the late Mesozoic volcanism occurred in two distinct episodes: Early–Middle Jurassic (176–173 Ma) and Late Jurassic–Early Cretaceous (151–138 Ma). The Early–Middle Jurassic dacite porphyry belongs to high-K calc-alkaline series, showing the features of I-type igneous rock. This unit has zircon εHf(t) values from +4.06 to +11.62 that yield two-stage model ages (TDM2) from 959 to 481 Ma. The geochemistry of the dacite porphyry is indicative of formation in a volcanic arc tectonic setting, and it is derived from a primary magma generated by the partial melting of juvenile mafic crustal material. The Late Jurassic–Early Cretaceous volcanic rocks belong to high-K calc-alkaline or shoshonite series and have A2-type affinities. These volcanics have εHf(t) and TDM2 values from +5.00 to +8.93 and from 879 to 627 Ma, respectively. The geochemistry of these Late Jurassic–Early Cretaceous volcanic rocks is indicative of formation in a post-collisional extensional environment, and they formed from primary magmas generated by the partial melting of juvenile mafic lower crust. The discovery of late Mesozoic volcanic and subvolcanic rocks within the southern GXR indicates that this region was in volcanic arc and extensional tectonic settings during the Early–Middle Jurassic and the Late Jurassic–Early Cretaceous, respectively. This indicates that the Mongol–Okhotsk oceanic plate was undergoing subduction during the Early–Middle Jurassic, and this ocean adjacent to the GXR may have closed by the Late Middle Jurassic–Early Late Jurassic.
... The Great Xing'an Range is located in the eastern Central Asian Orogenic Belt (CAOB) and contains a major Mesozoic volcanic belt that crops out over an area of 100,000 km 2 , dominating the Mesozoic stratigraphy of the Great Xing'an Range (IMBGMR 1991). Numerous studies have examined the late Mesozoic volcanic rocks of the Great Xing'an Range over the past decade (Zhao et al. 1989;Ge et al. 1999Ge et al. , 2000Ge et al. , 2001Guo et al. 2001;Fan et al. 2003;Wang et al. 2006;Xu et al. 2008Xu et al. , 2013aZhang et al. 2008aZhang et al. , 2010, and these studies have reported the geological and geochronological data, and established a relatively systematic geochronological framework for late Mesozoic volcanic rocks in the region, which has improved our understanding of the geodynamic setting. However, the petrogenesis of these late Mesozoic volcanic rocks and the processes that caused the magmatism in this area remain controversial, and various tectonic models have been proposed for the large-scale late Mesozoic volcanism in the Great Xing'an Range, including (1) a mantle plume model (Lin et al. 1998Ge et al. 1999Ge et al. , 2000Deng et al. 2004), (2) post-orogenic gravitational collapse and subsequent extension related to closure of the Mongol-Okhotsk Ocean (Guo et al. 2001;Fan et al. 2003;Meng et al. 2003;Zhang et al. 2007;Gou et al. 2010Gou et al. , 2013Ying et al. 2010;Wang et al. 2013), and (3) lithospheric delamination and consequent upwelling of asthenospheric material as a result of subduction of the Palaeo-Pacific Plate beneath the eastern Asian continent (Wang et al. 2006;Zhang et al. 2008aZhang et al. , 2010Dong et al. 2014). ...
... Numerous studies have examined the late Mesozoic volcanic rocks of the Great Xing'an Range over the past decade (Zhao et al. 1989;Ge et al. 1999Ge et al. , 2000Ge et al. , 2001Guo et al. 2001;Fan et al. 2003;Wang et al. 2006;Xu et al. 2008Xu et al. , 2013aZhang et al. 2008aZhang et al. , 2010, and these studies have reported the geological and geochronological data, and established a relatively systematic geochronological framework for late Mesozoic volcanic rocks in the region, which has improved our understanding of the geodynamic setting. However, the petrogenesis of these late Mesozoic volcanic rocks and the processes that caused the magmatism in this area remain controversial, and various tectonic models have been proposed for the large-scale late Mesozoic volcanism in the Great Xing'an Range, including (1) a mantle plume model (Lin et al. 1998Ge et al. 1999Ge et al. , 2000Deng et al. 2004), (2) post-orogenic gravitational collapse and subsequent extension related to closure of the Mongol-Okhotsk Ocean (Guo et al. 2001;Fan et al. 2003;Meng et al. 2003;Zhang et al. 2007;Gou et al. 2010Gou et al. , 2013Ying et al. 2010;Wang et al. 2013), and (3) lithospheric delamination and consequent upwelling of asthenospheric material as a result of subduction of the Palaeo-Pacific Plate beneath the eastern Asian continent (Wang et al. 2006;Zhang et al. 2008aZhang et al. , 2010Dong et al. 2014). ...
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This study presents new whole-rock major and trace element geochemistry, zircon U–Pb ages, and Hf-isotope compositions for volcanic rocks from the Manketouebo Formation of the central Great Xing’an Range, NE China. These data provide precise ages and information on the petrogenesis and source of the magmas that formed this formation, furthering our understanding of the geodynamic setting of the large-scale late Mesozoic magmatism in the Great Xing’an Range and other areas in NE China. The Manketouebo Formation in the study area is dominated by rhyolites and rhyolitic tuffs with minor trachydacites. The LA-ICP-MS zircon U–Pb dating indicates that these volcanic rocks formed between 143 and 139 Ma. The volcanic rocks contain high silica (66.70–79.91 wt.%) and total alkali (5.93–9.72 wt.%) concentrations, and low concentrations of MgO (0.08–1.15 wt.%), total FeO (0.68–4.50 wt.%), and CaO (0.10–2.56 wt.%). They are enriched in large-ion lithophile elements (LILEs; e.g. Rb, Th, and U) and light rare earth elements (LREEs), and depleted in high field strength elements (HFSEs; e.g. Nb, Ta, Ti, and P) and heavy rare earth elements (HREEs), indicating that they are similar to highly fractionated I-type igneous rocks. All of the magmatic zircons from the analysed samples have high initial 176Hf/177Hf ratios (0.282900–0.283093), positive εHf(t) values (7.48–14.19), and young Hf two-stage model ages (954–344 Ma) that suggest the primary magma that formed the volcanic rocks of the Manketouebo Formation was derived from the partial melting of Neoproterozoic to Phanerozoic juvenile crustal material, indicating in turn that significant crustal growth occurred at this time within the Xing’an Terrane. These data, combined with previous research into the spatial–temporal distribution of Mesozoic volcanic rocks in NE China, suggest that the Early Cretaceous magmatism in the Great Xing’an Range was influenced by both the subduction of the Palaeo-Pacific Plate and the closure of the Mongol–Okhotsk Ocean. This was a crucial period in the transformation from the Mongol–Okhotsk Ocean to the Palaeo-Pacific tectonic regimes. In summary, the early stages of Early Cretaceous magmatism in this area were related to the closure of the Mongol–Okhotsk Ocean, whereas the later stages of magmatism in this area and elsewhere in NE China were related to the subduction of the Palaeo-Pacific Plate.
... However, the first process is not favored for Chalukou ore-forming rocks because there are significant compositional gaps between contemporary mafic volcanic complexes and Chalukou felsic complex with the absence of intermediate magmas in the Chalukou ore district and little in the NGXR (F. Wang et al., 2006;Ge et al., 2000;Lin et al., 2003). Moreover, the mixing model does not support the origination of Chalukou ore-related rocks; no mafic enclaves were found in felsic rocks, and the Sr-Nd isotopic data show little involvement of old upper crustal material (Fig. 7b). ...
... The data for the Jurassic granites in Great Xing'an Range are fromSui et al. (2007) andZeng et al. (2011). The data for the J 3 -K 1 rhyolites in Great Xing'an Range are fromFan et al. (2003),Zhang et al. (2008b),Ge et al. (2000),Lin et al. (2003) andGou et al. (2010). ...
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The Chalukou porphyry Mo deposit (2.46Mt @ 0.087% Mo), located in the northern Great Xing’an Range, NE China, is the largest Mo deposit discovered in China so far. The host rocks consist of aplite porphyry, granite porphyry and quartz porphyry, and are intruded into Lower Ordovician intermediate-felsic volcanic-sedimentary rocks and pre-ore monzogranite and are cut by post-ore feldspar porphyry, diorite porphyry and quartz monzonite porphyry. Here, we present the zircon U-Pb ages, whole-rock geochemistry, Sr-Nd isotopic and zircon Hf isotopic data for the pre-ore, syn-ore and post-ore intrusive rocks. The Chalukou ore-forming porphyries intruded during 147 ~ 148 Ma and have high-silica, alkali-rich, metaluminous to slightly peraluminous compositions and are oxidized. They are enriched in large ion lithophile elements (e.g. K, Rb, U and Th), light REE and depleted in high-field strength elements (e.g. Nb, P and Ti). Depletions in Eu, Ba, Sr, Nb, Ta, P and Ti suggest that they have experienced strong fractional crystallization of plagioclase, biotite, hornblende and accessory minerals. The pre-ore monzogranite (~ 172 Ma) also belongs to the high-K calc-alkaline series. Highly fractionated REE patterns ((La/Yb) N = 19.6 ~ 21.7), high values of Sr/Y (54 ~ 69) and La/Yb (29 ~ 32), are adakite-like geochemical features. The post-ore rocks (~ 141-128 Ma) have similar geochemical characteristics with ore-forming porphyries except that quartz monzonite porphyry shows no Ba-Sr negative anomaly. All intrusive rocks have relative low initial 87Sr/86Sr (0.705413 ~ 0.707889) and εNd (t) values (-1.28 ~ + 0.92), positive εHf (t) values (+ 2.4 ~ + 10.1) and young two-stage Nd and Hf model ages (TDM2 (Nd) = 863 ~ 977 Ma, TDM2 (Hf) = 552 ~ 976 Ma). These geochemical and isotopic data are interpreted to demonstrate that the ore-forming porphyries formed by partial melting of the juvenile lower crust caused by underplating of mafic magmas in an intra-plate extensional setting. The pre-ore monzogranite formed by partial melting of thickened lower crust in a collisional setting caused by closure of Mongol-Okhotsk Ocean. The post-ore feldspar porphyry shares a similar magma source with ore-forming porphyry, but the quartz monzonite porphyry has a relatively deeper magma source region and has not experienced as much fractional crystallization. The transformation from middle Jurassic compression to late Jurassic extension created favorable conditions for the generation and emplacement of the ore-forming magma. The juvenile lower crust provided the main source of molybdenum for Chalukou deposit. Enrichment of Mo by fractional crystallization played an important role in concentrating Mo during formation of the Chalukou Mo deposit. The age (~ 147 Ma), high fluorine, and associated Pb-Zn deposits are all different from other major porphyry Mo deposits in NE China; Chalukou is a new mineral deposit type in the Great Xing’an Range.
... The felsic rocks also show a wide range of trace and rare earth (REE) element patterns. The most striking feature is the variation in Ba-Sr abundances (Ge et al., 2000a;Lin et al., 2000Lin et al., , 2003, revealing complexities in the magma sources. Geochemical studies also indicate the existence of adakitic volcanic rocks in the southern segment (Gao et al., 2005). ...
... All U and Pb data were corrected for mass fractionation. The blanks were (Zhang et al., 2008b); and (b) rocks from the southern segment (Zhao et al., 1989;Ge et al., 1999Ge et al., , 2000aGuo et al., 2001;Gao et al., 2005;Lin et al., 2003). 0.05 ng for Pb and 0.002 ng for U. ...
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Editor: R.L. Rudnick Keywords: Zircon U–Pb and 40 Ar– 39 Ar geochronology Mesozoic volcanic rocks Great Xing'an Range Delamination Northeastern China Mesozoic volcanic rocks and granitoids are widespread in the Great Xing'an Range, which is part of a large igneous province in the eastern China. However, the ages of the volcanic rocks, especially those in the southern segment of the range, are poorly constrained. Here we present zircon U–Pb and whole rock Ar–Ar ages of 43 volcanic rocks from the four recognized formations (Manketouebo, Manitu, Baiyingaolao and Meiletu) in the southern Great Xing'an Range. The volcanic rocks of the Manketouebo Formation have a large span of ages ranging from 174 to 122 Ma, while those of the Manitu Formation exhibit a smaller age range from 156 to 125 Ma. The Baiyingaolao and Meiletu volcanic rocks both have Early Cretaceous ages between 139 and 124 Ma. These data indicate that the mapped units are not strictly 'formations' and further studies are required to resolve this issue. However, when taken together, these new data define two episodes of magmatism (Late Jurassic and Early Cretaceous) with the Early Cretaceous volcanic rocks being dominant. Combined with previously published data from the northern Great Xing'an Range, and available age data from other parts of northeastern China and surrounding regions, two stages of magmatism, i.e., Jurassic and Early Cretaceous, can be identified throughout this part of Asia. The Jurassic rocks mainly comprise granites, while volcanic rocks are dominant in the Early Cretaceous. These two stages of magmatism form opposite spatial trends, that is, the Jurassic rocks become younger to the west, whereas the Cretaceous rocks become younger to the east. Between the two stages of magmatism, the 'magma gap' increases eastward in duration from less than 10 Ma in the Great Xing'an Range to more than 40 Ma in Japan. These trends can be explained by westward subduction of the Paleo-Pacific oceanic Plate and its control on subsequent geodynamic processes. Jurassic subduction of the oceanic slab caused crustal shortening and thickening, and formed the westward decrease in age of the granites with characteristics of an active continental margin, while volcanism was rare. By the end of the Jurassic, westward flat-slab subduction of the Paleo-Pacific Oceanic plate changed its direction to the north or northwest. This subsequently caused a transformation in tectonic regime from compression to extension in the Cretaceous and induced large-scale delamination of the thickened lower crust and lithospheric mantle. Delamination was initiated at the western margin of the subducting slab, and migrated eastward. Delamination and consequent upwelling of the asthenosphere triggered extensive volcanic eruption, with only minor granite emplacement. Similar age trends are also observed for other parts of eastern China, suggesting this model can also be applied to explain the geodynamic setting of the Mesozoic large igneous events in China and adjacent regions.
... The tectonic setting of the Great Xing'an Range from the middle Late Jurassic to Early Cretaceous is debated. The main views are as follows: (a) Influence of the mantle plume activity and related intraplate action (Ge, Lin, Sun, Wu, & Li, 2000;Wei, Michel, Patrick, Urs, & Dominique, 2008;Wu, Sun, & Lin, 1999) (Liao et al., 2012). An increasing amount of evidence collected in recent years suggests that the SGXR was not only affected by the Mongolian Okhotsk oceanic tectonic system but also by the subduction of the Palaeo-Pacific Plate (Ouyang, 2013;R. ...
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The Aobaotu Pb–Zn deposit (470,700 t; 1.51% Pb, 2.30% Zn) in the southern Great Xing'an Range, northeastern China, is hosted by the Late Jurassic volcanic tuff and structurally controlled by a near-east–west-trending fault. Three stages of mineralization were identified, namely, stage I of quartz ± pyrite veins, stage II of quartz–polymetallic sulphide veins, and stage III of late quartz–calcite veins. The quartz and calcite that formed in the three stages were selected for fluid inclusion and C–H–O isotope analyses. The results show that the ore-forming fluid of the deposit belongs to the H2O–CO2–NaCl system at a medium temperature (concentrated at 220–300°C) and in low salinity (0.7–12.1 wt% NaCl equiv). The δ¹³C values of the calcite and ankerite are in the range of −8.4 to −4.8‰, indicating that as a source of deep magma. The δDV-SMOW and values of quartz range from −108 to −88‰ and 4.55 to 5.85‰, respectively, indicating that the initial fluid of the Aobaotu deposit was a mixture of residual magmatic and meteoric water. Sulphur isotope analysis of the sulphide minerals, that is, sphalerite, galena, pyrite, and chalcopyrite, yield δ³⁴S value in a range of 1.44–4.94‰, indicating that sulphur is mainly derived from magma. In addition, the Pb isotopic composition of the sulphides indicates that the ore-forming material has a mixed crust–mantle source. Zircon U–Pb dating suggests that the formation of the Aobaotu deposit is genetically related to the granodiorite porphyry (130.3 ± 0.9 Ma). The combined geochronology and isotopic evidence suggest that the Aobaotu deposit is a magmatic-hydrothermal vein-type Pb–Zn deposit, opposite to a volcanic Pb–Zn deposit as suggested before. The Aobaotu deposit formed in an extensional tectonic setting caused by the rollback of the Palaeo-Pacific Plate.
... This area provides an ideal laboratory to study temporal changes in magma source regions and the evolution of accompanying geodynamic processes. Numerous studies have been carried out on ages, petrogenesis, tectonic settings, and geodynamics of the late Mesozoic volcanic rocks and granitoids (Zhao et al. 1989;Ge et al. 1999;Lin et al. 1999Lin et al. , 2003Ge et al. 2000;Lin et al. 2000;Guo et al. 2001;Shao et al. 2001,b;Fan et al. 2003;Gao et al. 2005;Wu et al. 2005;Wang et al. 2006;Zhang et al. 2006Zhang et al. , 2008aZhang et al. , 2008bZhang et al. , 2010Guo et al. 2010;Xu et al. 2013;Dong et al. 2014;Tang et al. 2014Tang et al. , 2015Tang et al. , 2016Yang et al. 2015;Gong et al. 2018;Gou et al. 2019). However, there are many different views on the Mesozoic magma generation processes and the tectonics of these voluminous magmas due to the overprinting by the Paleo-Pacific and Mongol-Okhotsk domains. ...
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Late Mesozoic volcanic rocks are widespread in the Great Xing’an Range (GXR), Northeast (NE) China. However, details of the tectono-magmatic evolution during the Late Mesozoic are poorly understood. In this paper, new zircon U–Pb, Lu–Hf, and whole-rock geochemical data from Late Mesozoic volcanics in the southern GXR, are used to further constrain the tectono-magmatic evolution of the region. Late Mesozoic magmatism in the GXR, eastern Mongolia and southern Transbaikalia occurred during the Early Cretaceous (120–140 Ma) and Late Jurassic (150–163 Ma) periods. Late Jurassic trachyandesites-trachytes show a low rare earth element and moderate light rare earth element (LREE) enrichment with no Eu anomalies. Early Cretaceous trachytes are characterized by an LREE enrichment and negative Eu anomalies. Contemporaneous rhyolites exhibit a significant LREE enrichment, A–type granitoid affinity, and pronounced negative Eu anomalies. Different negative Nb, Ta, and Ti anomalies, and positive zircon εHf(t) values, indicate that the ~160 Ma trachyandesites-trachytes are derived from partial melting of the lithospheric mantle that was metasomatized by subduction-related fluids. The ~125 Ma trachytes and rhyolites were possibly generated by partial melting of the accreted Meso-Neoproterozoic lower crust. New and previously published geochemical, isotopic and geochronological data from the southern GXR, eastern Mongolia and East-Transbaikalia, suggest that Late Jurassic–Early Cretaceous volcanism in the southern GXR occurred during the post-collisional extension after the closure of the Mongol–Okhotsk Ocean.
... (1) post-orogenic extension that resulted from continental collision related to the closure of the Mongol-Okhotsk Ocean (Ge et al., 2000;Meng, 2003;Xu et al., 2013;Tang et al., 2018), (2) extension following the roll-back subduction of the Paleo-Pacific plate (Lallemand et al., 2005;Maruyama and Okamoto, 2007;Zhang J H et al., 2010;Sun et al., 2013). Moreover, there is an intense debate about the possibility of combined action of Mongol -Okhotsk and Paleo-Pacific tectonic regime, and also, the timing and the affected area Xu et al., 2019). ...
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The extensive Late Mesozoic igneous rocks in NE China are mostly formed in an extensional setting. However, there is still controversy about how the Mongol‐Okhotsk Ocean and the Paleo‐Pacific Ocean effected on the lithosphere in NE China. In this paper, we conducted a comprehensive geochronology study of LA‐ICP‐MS zircon U‐Pb dating for the andesites of the Keyihe area, and investigated the petrogenesis and tectonic setting of these andesites based on their geochemical and Hf isotopic characteristics. The U‐Pb data yielded Early Cretaceous crystallization ages of 128.3 ± 0.4 Ma. Geochemically, the andesites contain high Sr (686–930 ppm) and HREE contents, low Y (11.9–19.8 ppm) and Yb (1.08–1.52 ppm) contents, and they therefore have high Sr/Y (42–63) and La/Yb (24–36) ratios, showing the characteristics of adakitic rocks. Moreover, they exhibit high K2O/Na2O ratios (0.57–0.81), low MgO contents (0.77–3.06 wt%), low Mg# value (17–49) and negative εHf(t) values (−1.7– −8.5) with no negative Eu anomalies, indicating that they are not related to the oceanic plate subduction. Based on the geochemical and isotopic data provided in this paper and regional geological data, we conclude that the Keyihe adakitic rocks were affected by the Mongol‐Okhotsk tectonic regime, forming in a transition setting from crustal thickening to regional extension thinning. They are derived from the partial melting of the thickened lower crust. The closure of the Mongol‐Okhotsk Ocean may ending at early Early Cretaceous and then there occurred the collisional orogenic process. The south part region of its suture belt was in a post‐orogenic extensional setting in the late Early Cretaceous.
... The volcanics are mainly alkaline (A). Rhyolite in the margin of the Songliao Basin exhibits A-type characteristics (Wang and Xu, 2003;Ge et al., 2000). The rhyolitic cover of the NAGC has A-type characteristics, and its age and geochemistry are consistent with the volcanics of the Yingcheng Group (K 1yc ) Li and Yu, 1993). ...
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New zircon U-Pb dates obtained by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), whole-rock geochemical data and Sm-Nd and Rb-Sr isotopic data are presented for miarolitic alkaline granites, porphyritic syenite and rhyolites of the Nianzishan A-type granitoid complex (NAGC) in the Great Xing’an Range-Songliao Basin in Northeast (NE) China. New crystallization ages of 112.95±0.93 and 114.1±1.71 Ma for granite and 118.6±0.51 Ma for porphyritic syenite were determined by high-precision LA-ICP-MS. The εNd(t) of the rocks range from +1.85 to +2.06, with Nd model ages (TDM1) from 671 to 821 Ma, indicating that the NAGC originated from juvenile source rocks and exhibits geochemical characteristics of A1- and AA-type granite which formed in an extensional setting. We attribute the magmatism to regional extension and lithospheric thinning caused by the subduction of the western Pacific Plate about 120 to 100 Ma.
... Consistent with the crystallization separation inherent within the same magma chamber, the incompatible elements in the magma chamber will gradually enrich in the lava (Ge et al., 2000;Aiko et al., 2008). It can be considered that the total amount of incompatible elements of volcanic rocks erupted at same times should be similar, while incompatible elements of different eruption time intervals should be different. ...
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A gas field consisting of volcanic reservoir rocks was discovered in block‐T units of the Xihu Sag, East China Sea Basin. The lithology of the volcanic rocks is dominated by tuff and reworked tuff. The lithofacies are dominated by base surge deposits of explosive facies. As the architecture model of volcanic facies is still uncertain, it has restricted the progress of exploration and development in this area. Using core and cuttings data, the lithology, lithofacies, geochemistry as well as grain size characteristics of volcanic rocks were analyzed. Based on these analyses, the volcanic rocks in the well section are divided into three eruptive stages. The transport direction of each volcanic eruption is analyzed using crystal fragment size analysis. The facies architecture of the block‐T units was established based on the reconstruction results of paleo‐geomorphology. The results show that the drilling reveals proximal facies (PF) and distal facies (DF) of the volcanic edifices. However, the crater‐near crater facies (CNCF) are not revealed. Compared with the reservoirs of the Songliao Basin, it is shown that the volcanic rocks in the Xihu Sag have good exploration potential; a favorable target area is the CNCF near the contemporaneous fault.
... Some investigators have suggested that the volcanic activity was triggered by the upwelling of a mantle plume ( Fig. 2a; Lin et al., 1998, https://doi.org/10.1016/j.jog.2019.01.012 Received 3 August 2018; Received in revised form 6 December 2018; Accepted 9 January 2019 1999; Shao et al., 1999;Ge et al., 1999Ge et al., , 2000, but this model has received little support (Zhang et al., 2008a;Li et al., 2014;Si et al., 2015). Fan et al. (2003) suggested that the volcanism was triggered by postorogenic diffuse extension rather than Mesozoic oceanic plate subduction or the upwelling of a mantle plume. ...
... A boundary separating the central-southern and northern regions of the Great Xing'an Range (GXR), recognized as the Xing'an-Mongolia Orogenic Belt, can be identified from Ulanhot to Aerxan by use of previously determined rock ages, assemblages, and chemical compositions ( Figure 2; Ge et al., 1999;Ge, Lin, Sun, Wu, & Li, 2000;Lü et al., 2004). Late Mesozoic magmatism in the northern GXR is thought to have been controlled mainly by either the MOO or the PP tectonic domain Sui et al., 2007;Wang et al., 2006), or a combination of the two . ...
... Wang et al., 2015). The petrogenesis and geodynamic setting of these igneous rocks have become a hot research topic in recent years, primarily due to their importance in deciphering the tectonic evolution of the CAOB (Ge et al., 2000;Tang et al., 2014Tang et al., , 2015Tang et al., , 2016Dong et al., 2014Dong et al., , 2016Ji et al., 2016;T. Wang et al., 2015;Wang et al., 2017). ...
... The influencing spatial extents of the circum-Pacific and the Mongol-Okhotsk tectonic system mainly include the Songliao Basin and to the east and west of the Songliao Basin and northern margin of the North China Craton (Xu et al., 2013). In the Songliao Basin, the earlier episodes of magmatism is about 157-138 Ma Wang, Zhao, et al., 2015;Xu et al., 2013), the second is about 133-106 Ma (Wang, Zhao, et al., 2015;Xu et al., 2013;Zhang, Pang, et al., 2007;Zhang, Chen, et al., 2008;Zhang, Cheng, et al., 2009 (Meng, 2003;Wang et al., 2002;Yan et al., 2002), subduction of the Palaeo-Pacific Plate (Zhao et al., 1996;Ren et al., 1998;Wu, Sun, Li, Jahn, & Wilde, 2002), magmatism associated with mantle plume activities (Ge, Lin, Sun, Wu, & Li, 2000;Lin et al., 1998), lithospheric thinning and asthenospheric mantle upwelling by subduction of the Pacific Plate beneath eastern China (Meng, Lu, et al., 2013;Wang, Zhou, Zhang, Ying, & Zhang, 2006), and so on. From Late Cretaceous to Palaeocene, the rate of subduction of the Palaeo-Pacific Plate decreased (from 13 to 4 cm/a) during 70-60 Ma (Northrup, Royden, & Burchfiel, 1995) corresponding with the 70.0 Ma of the mafic dykes. ...
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The ages and source of Late Cretaceous mafic dolerite dykes of the Songliao Basin were determined using geochronological, geochemical, zircon Hf, whole-rock Sr–Nd isotopic, and zircon fission tract. The results show that (a) petrographic data reveal doleritic, poikiloblastic textures, and amygdale structures of the dolerite dykes. (b) LA-MC-ICP-MS U–Pb analysis of zircons yielded an age of 70.0 ± 3.0 Ma of one of these mafic dykes in agreement with the zircon fission track age (69–68 Ma) of host rocks within uncertainty, placing them within the Late Cretaceous. (c) Geochemical researches indicate that the dykes are classified as the alkaline and tholeiitic series according to their major elements and characterized by high Na2O (2.79–4.89 wt.%), TiO2 (1.63–2.71 wt.%), and low K2O (0.46–2.45 wt.%). And they have enrichment of incompatible elements (e.g., K, Ti, Rb, Ba, Th, U, Nb, Ta, and REEs), high Rb/Sr (0.026–0.066), LaN/YbN (3.83–15.93), near-chondritic HREEs ([Gd/Yb]N = 1.78–3.37), low Sm/Nd (0.202–0.282) ratios, and with negligible Eu anomalies (Eu/Eu* = 0.98–1.06). The dykes contain relatively low amounts of radiogenic Sr, as shown by (⁸⁷Sr/⁸⁶Sr)i values (0.7037–0.7045), and have positive values of εNd(t) (3.66–5.40) and εHf (t) (2.66–7.45), suggesting that the mafic dykes have been derived from partial melting of the depleted lithospheric mantle and contaminated by crust in the source region and formed in back-arc rift settings caused by the subduction of the Pacific Oceanic Plate. All the above indicate large-scale extensional event in Songliao Basin NE China at about 70 Ma.
... These A1-type granites are significantly enriched in K, Rb and REEs with strong Eu, Ba, P, Ti and Sr negative anomalies (Fig. 4).The characteristics of low Ba and Sr indicate a source region of relatively shallow depth, possibly within the plagioclase or hornblende stability field in the lower crust (Ge et al. 2000;Ma et al. 2004). During the partial melting of plagioclase and hornblende, their residual phases reside in the source region, resulting in both the depletion of Ba, Sr and Eu and the heavy REEs (Ma et al. 2004;C. ...
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The tectonic setting and geodynamic model of the Greater Khingan Range (GKR) is highly controversial due to the lack of reliable geological, isotopic and geochronological evidence. In the current study, the Hailesitai pluton, located at the west of the suture between the northern and southern GKR in the east of the Central Asian Orogenic Belt, is selected to address this issue. These granites of the high potassium calc-alkaline series belong to the A1-type granites with typical geochemical characteristics including high contents of Al 2 O 3 , extremely low contents of Ti, P, enriched LREE, LILE, depleted HFSE, and a medium Eu negative anomaly. Laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) zircon U−Pb dating indicates that the granites can be divided into two stages: c. 152 and c. 161 Ma. The intrusion of A1-type granites at ~161 Ma implies that intra-plate orogenesis of the northern GKR started at c. 161 Ma at latest. The Hailesitai pluton has relatively homogeneous Hf isotope compositions with a ε Hf ( t ) value (+6.0 − +9.0), and two-stage depleted mantle model ages of 579−738 Ma show that the original magma is a mixture of juvenile and crustal source rocks. Extensional collapse of the Mongol−Okhotsk belt between the Siberia block and the northern GKR resulted in the formation of late Jurassic A1-type granites in the northern GKR. The Hailesitai pluton formed in response to post-orogenic extensional collapse of the Mongol–Okhotsk belt, coupled with back-arc extension related to Palaeo-Pacific plate subduction.
... The relative immobility of some incompatible elements (e.g., HFSE) in aqueous fluids has long been used to distinguish between the roles of melts and fluids as metasomatising agents (Labanieh et al., 2012;Yang et al., 2014a). The Th budget in subduction-related volcanic rocks (Gao et al., 2005;Ge et al., 2000Ge et al., , 1999Guo et al., 2001;Li et al., 2013;Lin et al., 2003;Zhang, 2009) and this study. is usually considered to be controlled by sediment recycling (Plank and Langmuir, 1998). ...
... It is generally considered that NE China was in an extensional environment during the Early Cretaceous time (Fan et al., 2003;Gao et al., 2005;Ge et al., 1999Ge et al., , 2000Ge et al., , 2001Guo et al., 2001;Lin et al., 1998Lin et al., , 2003Shao et al., 2001a;Wu et al., 2005a;Zhang et al., 2008aZhang et al., , 2010. This is confirmed by the presence of widespread coeval A-type granites (Gou et al., 2010;Li and Yu, 1993), metamorphic core complexes (Shao et al., 2001b;Zhang et al., 1998), and a large number of bimodal mafic and felsic dykes (Shao et al., 2001c;Zhang et al., 2006aZhang et al., , 2006b. ...
Article
We undertook zircon U-Pb dating and geochemical analyses of volcanic rocks from the Baiyingaolao Formation in the central Great Xing'an Range, northeastern China, with an aim to determine their age, petrogenesis and sources, which are important for understanding the Late Mesozoic tectonic evolution of the eastern section of the Central Asian Orogenic Belt. Lithologically, the Baiyingaolao Formation is composed mainly of rhyolites and rhyolitic tuffs, with minor trachy dacites. The zircons from three rhyolific tuffs and two rhyolites are euhedral-subhedral in shape, display fine-scale oscillatory growth zoning and have high Th/U ratios (0.72-2.60), indicating a magmatic origin. The results of LA-ICP-MS zircon U-Pb dating indicate that the volcanic rocks from the Baiyingaolao Formation in the study area formed during the Early Cretaceous time with ages of 134-130 Ma. Petrological and geochemical characteristics of these volcanic rocks suggest that they are all highly fractionated I-type igneous rocks, and their parental magmas were likely derived from the partial melting of lower crustal materials with plagioclase, hornblende and apatite as the residual phases. In addition, the volcanics sampled in this paper, tectonically located in the Xing'an terrain, have high initial Hf-176/Hf-177 ratios (0.282770-0.283035) and positive epsilon(Hf)(t) values (2.42-11.96), combined with young Hf two-stage model ages of 1134-541 Ma, reflecting that the crustal growth of the Xing'an terrain occurred during Neoproterozoic and Phanerozoic times. These data, combined with previous studies on the contemporaneous magma-tectonic activities in NE China, suggest that the generation of the Early Cretaceous volcanic rocks in the central Great Xing'an Range was related to the lithospheric delamination caused by the subduction of the Paleo-Pacific plate.
... The rhyolite samples in this study plot in the A-type granite field in several of the discriminant diagrams of Whalen et al. (1987) (Fig. 10). The rhyolites are also strongly depleted in Ba and Sr (Fig. 8b); a feature of the Late Mesozoic rhyolites in the Great Xing'an Range, which are also accompanied by basaltic rocks (Ge et al., 2000). Thus, the heat source of the rhyolite might be provided by the coeval basaltic rocks. ...
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A 125m-wide bimodal composite dyke complex, consisting of rhyolite and dolerite dykes, was emplaced into Cretaceous volcanic strata of the Songmuhe Formation in the Jiamusi Block of NE China. The dolerite dykes are sub-vertical, strike north-south, and intruded into both the country rocks and rhyolite dykes soon after the latter solidified. SHRIMP zircon U-Pb dating shows that the rhyolite dykes were emplaced at 100±2Ma and the dolerite dykes were also most likely emplaced at 100±2Ma. The rhyolite is characterized by enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE), and depletion in high-field strength elements (HFSE). It shows a significant negative Eu anomaly, and has εNd(t) values ranging from 0.49 to 1.66 and two groups of initial 87Sr/86Sr ratios at 0.7045 and 0.7061. The rhyolite displays the compositional signature of Peraluminous Ferroan Granitoid, indicating it was derived by either differentiation of basalt and/or low pressure partial melting of crust. The dolerite is also characterized by enrichment in LILE and LREE, and depletion in HFSE. It has a weak negative Eu anomaly and has εNd(t)=-1.22 to +3.26, and (87Sr/86Sr)i=0.7057-0.7074. The dolerite originated from partial melting of lithospheric mantle which was affected by subducted oceanic crust, and experienced different amounts of crustal contamination. Such bimodal dyke complexes are an important indicator of crustal extension under the influence of mantle processes. Thus the dyke complex in the Jiamusi Block indicates mid-Cretaceous intra-plate extension in NE China related to the subduction of the paleo-Pacific plate along the eastern Eurasian continental margin. When compared with Mesozoic bimodal magmatism further to the west, our new data support a temporal eastward migration of magmatism over a distance >1000km from ~160Ma to ~100Ma. This was most likely associated with roll-back of the paleo-Pacific Plate and consequent upwelling of asthenospheric mantle.
... enriched continental lithospheric mantle, which had been previously metasomatized by £uids derived from subducted slabs during the closure of the paleo-Asian and/or Mongolia^ Okhotsk Oceans. Rhyolite lavas can be produced either through remelting of lower ma¢c crust or fractional crystallization of mantle-derived melts (e.g.,Borg and Clynne, 1998).Ge et al. (2000)noted that rhyolite lavas from the Da Hinggan Mountains could be grouped into two petrogenetic types. One type, containing relatively higher TiO 2 contents and high initial 87 Sr/ 86 Sr ratios ( s 0.710), was probably derived from remelting of lower/middle crust (Ge et al., 2001), whereas the low-TiO 2 type was formed through magma di¡er ...
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Late Mesozoic calc-alkaline volcanism in the northern Da Hinggan Mountains (NDHM), NE China, exhibits geochemical and Sr–Nd isotopic characteristics similar to those of Cenozoic calc-alkaline volcanism in the Basin and Range Province, USA. Whole-rock K–Ar dating results show that these volcanic sequences were erupted during 138–116 Ma, composed of basaltic andesites/trachyandesites (Group 1), hornblende andesites/trachytes (Group 2) and rhyolite lavas (Group 3). They are characterized by low MgO contents (≤4.20%), LILE, LREE enrichment and significant Nb–Ta depletion, as well as a little depleted to slightly enriched Nd and weakly enriched Sr isotopic ratios (Group 1: initial 87Sr/86Sr=0.70502–0.70572; ϵNd(t)=−0.78 to +0.91; Group 2: initial 87Sr/86Sr=0.70497–0.70518; ϵNd(t)=+0.86 to +1.26; Group 3: initial 87Sr/86Sr=0.70510–0.70635; ϵNd(t)=−0.41 to +0.25). The systematic variations in major and trace elements, homogeneous Sr–Nd isotope data and temporal consistency among three volcanic groups, indicate that they were derived from a similar mantle source metasomatized by fluids related to the closure of the paleo-Asian and/or Mongolia–Okhotsk Oceans, and were produced through different degrees of fractional crystallization of the primary melts. Group 1 basaltic rocks were formed through removal of olivine and pyroxene of the primary melts, while Group 2 trachytes, which contain the lowest LREE contents (e.g., La=24–28 ppm) and relatively less enriched Sr and higher Nd isotope ratios, were generated after removal of a few percent of LREE-rich minerals such as hornblende, clinopyroxene and apatite of melts like Group 1. Group 3 rhyolite lavas exhibiting the highest abundances of strongly incompatible elements such as Rb and K, moderate LREE contents (e.g., La=28–53 ppm) as well as apparently negative Eu and Sr anomalies, represent the final crystallized products following a plagioclase-predominant fractionation of melts like Group 2. The low MgO contents and evolved affinities of the volcanic rocks imply that beneath the NDHM there existed many crustal magma reservoirs throughout the eruption episodes, in which mantle-derived primary melts had experienced intense differentiation. These facts, in combination with the contemporaneous basin and range tectonic regime, suggest that the extensive calc-alkaline volcanism in the NDHM was attributed to post-orogenic diffuse extension rather than either an upwelling mantle plume or Mesozoic oceanic plate subduction.
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Southern Manzhouli experienced a tectonic regime transformation from compression to extension in the late Mesozoic, but there is a lack of petrological and detailed chronological evidence. In addition, the lack of research on volcanic lithofacies and eruption sequence restricted the study of magmatic evolution and the division and correlation of regional volcanic rock strata. Based on systematic research of volcanics, volcanic facies, chronology and geochemistry, two stages of volcanics were identified; the first stage named trachyte series was formed in the late Middle Jurassic (167Ma‐163Ma), its eruption rhythm is pyroxene trachyandesite‐trachyandesite‐trachyte, and its origin rock is basic volcanics from thickened lower crust, and the tectonic setting is the collision orogeny after the closure of Mongolia Okhotsk Ocean. The second stage is a bimodal volcanic rock, formed in the early Late Jurassic (163Ma‐160Ma). The eruption rhythm of basic volcanics of the second stage is basaltic andesite‐basalt‐olivine basalt, which comes from the metasomatized lithospheric mantle, the acidic volcanic of it is characterized by the eruption rhythm of sedimentary facies‐explosive facies‐overflow facies, and came from the partial melting of newly formed lower crust, which shows the characteristics of A‐type granite. The tectonic setting of the second stage is the extension of the lithosphere after the collision of Mongolia Okhotsk Ocean. The changes in the formation age and tectonic setting of the two stages volcanics demonstrated that the transition time from the compressive system to the extensional system in the southern Manzhouli is about 163 Ma.
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Dikes are great significance for studying the nature of the crust-mantle and the evolution of continental dynamics. In this paper, we investigated the dikes from the inner part of the Baiyintaohai Basin of the Suolun region in the DaXing’anling Mountains, China. Geochronological and geochemical analyses were performed on selected dike samples. These dikes consist of diorite porphyrite and granite aplites formed in the Late Triassic (221–228 Ma). The diorite porphyrites have low SiO2 contents of 37.32–58.29 wt%. These rocks are characterized by enrichment in macroionic lithophile elements (LILEs, Rb, K), strong depletion of Sr and Ti, and relative depletion of Nb, Ta. These results indicate that the diorite porphyrites were originated from an enriched lithospheric mantle and was previously accounted for by subduction-related fluids. The primitive magma subsequently underwent varying amounts of fractionated crystallization. In comparison, the granite aplites have relatively high SiO2 contents of 61.51 to 74.69 wt% (average is 70.15 wt%) and low MgO, CaO contents. Geochemical signatures show the granite aplites enrich LILEs and REEs, display negative Eu anomalies, indicating they were derived from the partial melting of late Mesoproterozoic to Neoproterozoic juvenile crustal material. With this contribution, we suggest that dikes, consisting in granite aplite and diorite porphyrites from the Suolun region, crystallized in a post-closure. Among them, the diorite porphyrites in the Suolun area provide reducing agents for the formation of uranium deposits, and granite aplites provide the material source for uranium ore generation.
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The Central Asian Orogenic Belt (CAOB) is the largest accretionary orogenic belt in the world and its formation involved a complicated process of arc–continent collision. Large‐scale Mesozoic volcanic activity in the Great Xing'an Range (GXAR) in northeastern China, which constitutes part of the eastern CAOB, has received much recent research attention. However, the petrogenesis and formation mechanism of the late Mesozoic igneous rocks remain enigmatic. This paper investigates the geochronology, petrogenesis, and formation mechanism of late Mesozoic magmatic rocks in the Kelihe area of the GXAR based on zircon U–Pb dating, petrology, and geochemistry. Late Mesozoic magmatism in the Kelihe area occurred during the Late Jurassic (165–155 Ma) and Early Cretaceous (130–120 Ma). These igneous rocks generated by this magmatism are characterized by high SiO2 (69.97–75.49 wt%) and low MgO (0.11–0.68 wt%), Cr (10–30 ppm), Co (0.2–2.6 ppm), and Ni (0.5–1.6 ppm) contents. Trace elements show enrichment in Rb, Th, U, Zr, and K, and depletion in Ba, P, Nb, and Ti. These features indicate that the rocks were derived from partial melting of the crust. Furthermore, the rhyolites have high Na2O (5.02–5.44 wt%) and K2O (3.94–4.88 wt%) contents, similar to those of melts formed by the partial melting of basaltic crust. Combining the present results with the findings of previous studies, it is inferred that the Mesozoic igneous rocks formed in a post‐collisional extensional setting related to lithospheric thinning and asthenospheric upwelling after the closure of the Mongol–Okhotsk Ocean. Late Mesozoic magmatism in the Kelihe area occurred during the Late Jurassic (165–155 Ma) and Early Cretaceous (130–120 Ma). Combining the present results with the findings of previous studies, it is inferred that the Mesozoic igneous rocks formed in a post‐collisional extensional setting related to lithospheric thinning and asthenospheric upwelling after the closure of the Mongol–Okhotsk Ocean.
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The Sandaowanzi gold deposit is an extremely Au-rich deposit in the Northern Great Hinggan Range in recent years. Zircon U–Pb geochronology, Hf isotope analysis, and the geochemistry of andesites of the Longjiang Formation from the Sandaowanzi gold deposit were used to investigate the origin, magmatic evolution as well as mineralization and tectonic setting of the Early Cretaceous epithermal gold deposits in the northern Great Hinggan Range area. Zircon U–Pb dating reveals an emplacement age of 123.4 ± 0.3 Ma, indicating that the andesites of the Sandaowanzi gold deposit was formed during the Early Cretaceous. The andesites are enriched in light rare earth elements relative to heavy rare earth elements and have weak negative Eu anomalies (δEu = 0.76–0.90). The rocks are also enriched in large-ion lithophile elements, such as Rb, Ba, Th, U, and K, and depleted in the high-field-strength elements, such as Nb, Ta, and P. These characteristics are typical of volcanic rocks related to subduction. Igneous zircons from the andesite samples have relatively homogeneous Hf isotope ratios, 176Hf/177Hf values of 0.282343–0.282502, εHf(t) values of − 12.58 to − 6.95, and two-stage model ages (TDM2) of 1743–1431 Ma. The characteristics of the andesites of the Longjiang Formation are consistent with derivation from partial melting of enriched mantle wedge metasomatized by subducted-slab-derived fluids. These rocks formed in an extensional environment associated with the closure of the Mongol–Okhotsk Ocean and subduction of the Paleo-Pacific Plate. Mineralization occurred towards the end of volcanism, and the magmatic activity and mineralization are products of the same geodynamic setting.
Article
The newly discovered Dongyang low‐sulphidation epithermal Au deposit is located in central‐eastern Fujian Province, coastal SE China. Ore bodies occur in Late Jurassic rhyolite porphyry, rhyolite, and dacitic crystal tuff lava. In this study, rhyolite and dacitic crystal tuff lava are dated to 151.9 ± 0.4 Ma and 158.3 ± 0.4 Ma, respectively, and belong to the second member of the Nanyuan Formation. They are high in K2O (6.91–3.81 wt%) and Na2O/K2O (0.55–0.02), strongly peraluminous (A/CNK = 2.11–1.67) and high‐K calc‐alkaline or shoshonitic. They contain low ∑REEs (248–125 ppm), are enriched in Rb, K, Au, and depleted in Ba, Sr, P, Zr, Hf, and have slightly negative Eu anomalies (δEu = 0.94–0.56), suggesting that they are weakly fractionated felsic volcanic rocks. The zircon εHf(t) values (−11.2 to −5.4; two‐stage model ages = 2,650–2,128 Ma) suggest that they were mainly derived from Palaeoproterozoic crust. Lead isotope compositions also imply a dominantly lower crustal source. Detailed geological characteristics and elemental and isotopic data suggest that the oxidizing and weakly fractionated nature of the Dongyang high‐K felsic magma may have played a key role in Au mineralization. Integrating new and published data on the tectonic evolution, we suggest that the Late Jurassic Au mineralization and its causative magmatism actually extended to the SE China coastal area. The Dongyang rhyolite and dacitic crystal tuff lava may have been generated from partial melting of the crust caused by underplating of mantle‐derived magmas in an extensional environment. Regional extension may have been related to the NW‐directed roll‐back of the Palaeo‐Pacific Plate beneath the South China Block.
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Duolun volcanic‐eruption basin is part of the Mesozoic Tectono‐Magmatic Belt in the Great Khingan–Taihang Mountains. A lot of previous studies about this region have been made in geochronology, geomorphic genesis, magmatic origin, and Mesozoic Plate tectonic evolution. This article summarizes petrological features of volcanic rocks, lithofacies, volcanic sedimentary sequences, volcanic mechanism, and characters of volcanic eruptions in Duolun volcanic‐eruption basin. The volcanic sedimentary strata in this region are distributed along a series of NE and NNE tectonic belts, and accumulation thicknesses are controlled by volcanic edifices. We identified a total of seven volcanic edifices in Duolun volcanic‐eruption basin. For some typical volcanic edifices, we had studied their compositions, structures, geometries, and spatial distributions in detail, setting up regional volcanic tectonic framework. In the Manketouebo (J3m) cycle, the intensity of the eruption was large, characterized by large broken volcanoes in the early stage, and small dome and cone volcanoes in the late stage. In the Baiyingaolao (J3b) cycle, the strong volcanic activities manifested as Plinian‐type, are characterized by a large circular or nearly circular caldera at the top, moreover, late extrusive and intrusive domes in different cycles, ring faults and radial faults were also developed. Geochemical researches indicate that Duolun volcanic rocks have the basic characteristics of crust–mantle mixed source, and the tectonic environment for the Late Jurassic volcanic rocks is related to the collisional orogeny. Our work has great significance for further research on genesis of volcanic rocks, magma evolution, deep dynamics mechanism and their relationship between mineralization.
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The spatial-temporal extent and influence of the Mongol-Okhotsk and Paleo-Pacific tectonic regimes in northeast (NE) China and adjacent areas during late Mesozoic times have long been controversial. As a superimposed rift system which formed due to extensive intracontinental extension during the Late Jurassic to Early Cretaceous periods, the Hailar-Tamtsag basin is a key area to study the relationship between the Mongol-Okhotsk and Paleo-Pacific tectonic regimes and their superposition. With the aim of constraining the evolution of those two regimes, in this paper, the Tanan depression, which is a second-order structural unit in the western part of the Hailar-Tamtsag basin, has been chosen as the research object. On the basis of structural analysis of three-dimensional (3D) seismic data in the Tanan depression, and taking into account the controlling effect and influence of the pre-existing facies on the basin evolution, the deformation events in the Early Cretaceous can be subdivided into four periods: 1) A NW-SE trending extension during the deposition of the Tongbomiao Formation to the upper part of the second Member of the Nantun Formation; 2) A NW-SE trending compression during the deposition of the upper part of the second Member of the Nantun Formation to the first Member of the Yimin Formation; 3) A near EW trending extension during the deposition of the second Member to the lower part of third Member of the Yimin Formation; 4) A near EW trending compression during the deposition of the upper part of the third Member of the Yimin Formation. Additionally, we identify compressional structures in the basement in the southeast part of the depression, which is a key study that resulted from the Mongol-Okhotsk collisional orogeny during the Late Jurassic. The above five major deformational events make up a relatively complete tectonic deformation sequence of the Hailar-Tamtsag basin. Moreover, the deformation sequence, together with other available information from the literature in NE China and adjacent areas, including petrology, geochemistry and geochronology data, also record the whole process from the orogenic stage after the closure of the Mongol-Okhotsk Ocean, over the post-orogenic collapse of the Mongol-Okhotsk orogen, to the weakening of the influence of the Mongol–Okhotsk regime, and eventually to be replaced by the Paleo-Pacific tectonic regime. Considering that the superposition and transformation of the two tectonic regimes involves almost all the geological process in NE China and adjacent area during the late Mesozoic, the complete geological record in the Tanan depression during this period provides new constraints on the research of regional tectonic evolution, and the model of multiphase deformation is also expected to have useful implications for future studies of complex basin systems.
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The Derbur lead–zinc deposit is located in the Derbugan metallogenic belt in the north‐western portion of the Mesozoic Hailaer‐Genhe volcanic basin in the northern Great Xing'an Range. This deposit occurs in the Middle Jurassic intermediate–mafic volcanic rocks of the Tamulangou Formation and is spatially and temporally associated with acidic pyroclastic rocks. The host rocks are bedded trachyandesite and rhyolitic lithic‐crystal tuffs, and basaltic‐andesitic aplite veins are associated with the ore body. Because the deposit is a hypabyssal low‐temperature hydrothermal Pb–Zn deposit associated with volcanism, to determine the precise petrogenesis of the volcanic rocks, this study analysed the zircon U–Pb ages of the trachyandesite and rhyolitic lithic‐crystal tuffs, the Sr–Nd–Pb isotopic geochemistry of the trachyandesite and basaltic‐andesitic aplite, and the whole‐rock geochemistry of all three rock types. The results showed that the trachyandesite and basaltic‐andesitic aplite belong to the shoshonitic series and have similar whole‐rock and isotopic geochemical characteristics, including enrichments in large‐ion lithophile elements and light rare earth elements and depletions in high‐field‐strength elements. They also have low initial ⁸⁷Sr/⁸⁶Sr values of 0.705007–0.705240 and εNd(t) values of +0.6 to +1.7, with model ages (TDM) of 699–883 Ma. The ratios of ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb vary from 18.438 to 18.476, 15.570 to 15.577, and 38.254 to 38.320, respectively, with μ values of 9.40–9.41. In contrast, the rhyolitic lithic‐crystal tuffs are characterized by high SiO2 contents (73.44–79.48 wt.%); low Al2O3 (11.36–12.53 wt.%), TiO2 (0.14–0.18 wt.%), and K2O + Na2O (3.48–3.89 wt.%, Na2O ≤ K2O) contents; and low Mg# values (0.17–0.41), indicating that they belong to the calc–alkaline series. Additionally, they have relatively low REE contents and strong Sr depletions. LA‐ICP‐MS zircon U–Pb dating of the trachyandesite and rhyolitic lithic‐crystal tuffs indicates that their ages are 167.0 ± 2.0 Ma and 164.8 ± 1.6 Ma, respectively. We conclude that the trachyandesite and the basaltic‐andesitic aplite were derived from the partial melting of lower crustal material assimilated by a depleted lithospheric mantle that was subsequently metasomatized by subducted slab‐derived fluids. The rhyolitic lithic‐crystal tuffs likely originated from the partial melting of accreted lower crust. In summary, because the acidic volcanism was accompanied by increasingly felsic volcanism, bimodal volcanic rocks were produced. Among volcanogenic deposits, bimodal volcanic rocks are the most favourable ore‐hosting rocks, and ore‐forming materials were contributed by the magmatic system. These processes created conditions conducive to the formation of large‐scale Ag, Pb, and Zn mineralization in this area.
Article
We undertook zircon U–Pb dating and geochemical analyses of volcanic rocks from the Manitu Formation in the Hongol area, northeastern Inner Mongolia, to determine their age, petrogenesis and sources, which are important for understanding the Late Mesozoic tectonic evolution of the Great Xing'an Range. The volcanic rocks of the Manitu Formation from the Hongol area consist primarily of trachyandesite, based on their chemical compositions. The zircons from two of these trachyandesites are euhedral–subhedral in shape, display clear oscillatory growth zoning and have high Th/U ratios (0.31–1.15), indicating a magmatic origin. The results of LA-ICP-MS zircon U–Pb dating indicate that the volcanic rocks from the Manitu Formation in the Hongol area formed during the early Early Cretaceous with ages of 138.9–140.5 Ma. The volcanic rocks are high in alkali (Na2O + K2O = 6.22–8.26 wt%), potassium (K2O = 2.49–4.58 wt%) and aluminium (Al2O3 = 14.27–15.88 wt%), whereas they are low in iron (total Fe2O3 = 3.76–6.53 wt%) and titanium (TiO2 = 1.02–1.61 wt%). These volcanic rocks are obviously enriched in large ion lithophile elements, such as Rb, Ba, Th and U, and light rare earth elements, and are depleted in high field strength elements, such as Nb, Ta and Ti with pronounced negative anomalies. Their Sr–Nd–Pb isotopic compositions show positive ∊Nd(t) (+0.16‰ to+1.64‰) and low TDM(t) (694–767 Ma). The geochemical characteristics of these volcanic rocks suggest that they belong to a shoshonitic series and were likely generated from the partial melting of an enriched lithospheric mantle that was metasomatised by fluids released from a subducted slab during the closure of the Mongol–Okhotsk Ocean. Elemental and isotopic features reveal that fractional crystallization with the removal of ferromagnesian minerals, plagioclase, ilmenite, magnetite and apatite played an important role during the evolution of the magma. These shoshonitic rocks were produced by the partial melting of the enriched lithospheric mantle in an extensional regime, which resulted from the gravitational collapse following the final closure of the Mongol–Okhotsk Ocean in the Middle–Late Jurassic.
Article
The Early Paleozoic Bianjiadayuan complex of monzodiorite and biotite-bearing monzogranite is located in the southern part of the Huanggangliang–Ganzhuermiao metallogenic belt, southern Greater Khingan, China. The 206Pb/238U ages of zircons from the monzodiorite and biotite-bearing monzogranite are 129.67 ± 0.4 and 143.20 ± 1.2 Ma, respectively. The total REE contents of the rocks are very high, especially LREEs, suggesting obvious LREE and HREE fractionation; the monzodiorite has weak negative Eu anomalies, the biotite-bearing monzogranite highly negative anomalies. These rocks are all rich in large ion lithophile elements (Rb and U) and relatively depleted in high-field-strength elements (Nb and Ta). The monzodiorites and biotite-bearing monzogranites have ε Hf(t) values of 1.39–5.69 and 0.86–2.46 and t DM2 ages of 0.82–1.09 and 1.04–1.24 Ga, respectively. In the ε Hf(t)–t diagram, the data plot between the chondrite and depleted mantle lines of Hf isotopic evolution, showing the rocks were derived mainly from new crustal material that had been derived by the differentiation of the mantle. We conclude that this area underwent an important episode of crustal growth in the Meso–Neoproterozoic. The relationship between the intrusive complex and the orebody was related to faulting; we infer that the Bianjiadayuan Pb–Zn polymetallic deposit is mainly related to Late Jurassic–Early Cretaceous (144–129 Ma) magmatic activity, and it represents large-scale mineralisation in the context of Paleo-Pacific plate subduction and regional extension.
Article
The primary object of this fundamental research is to reveal new study of Late Jurassic Manketou Obo Formation and Early Cretaceous Manitu Formation, Baiyingaolao Formation, in Huiyin Obo area, East Ujimqin County, Inner Mongolia. Several sets of experiments were carried out to test the validity of three formations’ age, and these forms can be contrasted with Chagannuoer Formation and Bulagehada Formation from “1/250000 Regional Geology Survey in Hesigewula Farm.” As a result of our study, we concluded that further research into the Mesozoic volcanic rocks on the Huiyin Obo is necessary.
Article
Abstract A zircon U‐Pb geochronological study on the volcanic rocks reveals that both of the Zhangjiakou and Yixian Formations, northern Hebei Province, are of the Early Cretaceous, with ages of 135–130 Ma and 129–120 Ma, respectively. It is pointed out that the ages of sedimentary basins and volcanism in the northern Hebei ‐western Liaoning area become younger from west to east, i. e. the volcanism of the Luanping Basin commenced at c. 135 Ma, the Luotuo Mount area of the Chengde Basin c. 130 Ma, and western Liaoning c. 128 Ma. With a correlation of geochronological stratigraphy and biostratigraphy, we deduce that the Xing'anling Group, which comprises the Great Hinggan Mountains volcanic rock belt in eastern China, is predominantly of the early‐middle Early Cretaceous, while the Jiande and Shimaoshan Groups and their equivalents, which form the volcanic rock belt in the southeastern coast area of China, are of the mid‐late Early Cretaceous, and both the Jehol and Jiande Biotas are of the Early Cretaceous, not Late Jurassic or Late Jurassic‐Early Cretaceous. Combining the characteristics of the volcanic rocks and, in a large area, hiatus in the strata of the Late Jurassic or Late Jurassic‐early Early Cretaceous between the formations mentioned above and the underlying sequences, we can make the conclusion that, in the Late Jurassic‐early Early Cretaceous, the eastern China region was of high relief or plateau, where widespread post‐orogenic volcanic series of the Early Cretaceous obviously became younger from inland in the west to continental margin in the east. This is not the result of an oceanward accretion of the subduction belt between the Paleo‐Pacific ocean plate and the Asian continent, but rather reflects the extension feature, i.e. after the closure of the Paleo‐Pacific ocean, the Paleo‐Pacific ancient continent collided with the Asian continent and reached the peak of orogenesis, and then the compression waned and resulted in the retreating of the post‐orogenic extension from outer orogenic zone to inner part (or collision zone). The determination of the eruption age of the volcanics of the Zhangjiakou Formation definitely constrains the switch period, which began in the Indosinian and finished in the Yanshanian, that is, 140–135 Ma. The switch is concretely the change from the approximate E‐W Paleo‐Asian tectonic system to the NE to NNE Pacific system, and the period is also the apex of a continent‐continent collision and orogenesis of subduction, being consumed and eventually disappearing of the Paleo‐Pacific ancient continent, and all the processes commenced in the Indosinian. While the following post‐orogenic large‐scale eruption in the Early Cretaceous marks the final completeness of the Paleo‐Pacific structure dynamics system.
Article
We have undertaken major and trace element analyses of volcanic rocks in Northeast China, as well as U–Pb dating and Hf isotopic analysis of their zircons, in order to determine the petrogenesis and tectonic setting of the volcanics. Mesozoic volcanism in the southern Manzhouli area occurred in two stages: Middle to Late Jurassic (164–147 Ma) and Early Cretaceous (142–123 Ma). The first stage is represented by the Tamulangou, Jixiangfeng, and Qiyimuchang formations. The Jixiangfeng Formation (162–156 Ma) is a rhyolite–trachyte dominated unit that lies between two basalt units, namely the underlying Tamulangou (164–160 Ma) and overlying Qiyimuchang (151–147 Ma) formations. The second igneous stage is dominated by rhyolitic lavas and tuffs of the Shangkuli Formation and basaltic rocks of the Yiliekede Formation, and they yield zircon U–Pb ages of 142–125 and 135–123 Ma, respectively. Basaltic rocks of the Tamulangou and Yiliekede formations have a wide range of MgO contents (1.64–9.59 wt%), but are consistently depleted of Nb and Ta and enriched with incompatible trace elements such as large ion lithophile elements (LILEs) and light rare earth elements (LREEs). Trachytes and rhyolites of the Jixiangfeng and Shangkuli formations are characterized by enrichment in LILEs and LREEs relative to HFSEs and HREEs, and with negative Nb, Ta, P, and Ti anomalies and positive Hf(t) values (3.49–9.98). These data suggest that basaltic volcanic rocks in southern Manzhouli were generated by fractional crystallization of a common parental magma, which was derived by partial melting of metasomatized (enriched) lithospheric mantle, whereas the trachytic and rhyolitic magmas were produced by the melting of lower crustal mafic and felsic granulites, respectively. Geochronological data indicate that Mesozoic volcanism in southern Manzhouli was initiated in the Middle to Late Jurassic and continued into the Early Cretaceous. It was mainly induced by lithospheric extension after the closure of the Mongol–Okhotsk Ocean.
Article
The Songliao Basin is characterized by episodic rifting and intense volcanism during its early development, and forms a key concealed part of the Late Mesozoic magmatic province of NE China. Few precise geochronological and geochemical data were previously available for the volcanic elements of this basin, restricting understanding of its geodynamic setting and evolution. We present new SHRIMP U–Pb zircon ages and geochemical data for the volcanic rocks from the northern Songliao Basin, which limit this volcanism to the Early Cretaceous period (115–109Ma). Although dominated by rhyolite, the rocks cover a wide compositional spectrum encompassing trachyandesite, basaltic trachyandesite, trachyte and dacite. This suite exhibits a range of geochemical signatures characteristic of subduction-related genesis, falling into a high-K calc-alkaline series, with enrichment in large ion lithophile elements (LILE) and light rare earth elements (LREE), and weak depletion in high field strength elements (HFSE) and heavy rare earth elements (HREE). The suite also shares a common isotopic composition, consistent with derivation from partial melting of a single depleted mantle source. This Early Cretaceous volcanism occurred in an extensional back-arc setting associated with the subduction of the Paleo-Pacific plate, large scale upwelling of the asthenosphere, and intensive lithospheric thinning of the eastern continental margin of NE China which may have lasted until ca. 109Ma.
Article
Abstract Mesozoic bimodal volcanic rocks of basaltic andesite and rhyolite are widely distributed in the Da Hinggan Range, but their petrogenetic relationships and geodynamic implications are rarely constrained. Detailed studies on doleritic and porphyry dikes in the Zhalantun area indicate that they display features of magma mixing, suggesting their coeval formation. In situ zircon U-Pb dating shows that the porphyry was emplaced in the Early Cretaceous with a 206Pb/238U age of 130±1 Ma. Zircons from the dolerite also yield an Early Cretaceous emplacement age of 12412 Ma although some inherited zircons have been identified. These age results indicate that the Early Cretaceous was an important period of magmatism in the Da Hinggan Range. Zircons from porphyry are characterized by positive value of εHf(t) as high as 10.3±0.5 with Hf depleted mantle model age of 349–568 Ma, whereas magmatic zircons from the dolerite have εHf(t) value of 11.0±1.4 with Hf depleted mantel model age of 342–657 Ma, consistent with those from the porphyry. Considering other data on the geological evolution of this area, it is concluded that the mafic magma originated from the partial melting of Paleozoic enriched lithospheric mantle, whereas the felsic magma came from recycling of juvenile crust formed during the Paleozoic. Both of the protoliths are closely related to the subduction of the Paleo-Asian Ocean during the Paleozoic, indicating that the Paleozoic is an important period of large-scale crustal growth in the area
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Late Mesozoic volcanism is widespread throughout NE China. On the basis of lithological associations and spatial relationships, the volcanic rocks in the Lesser Hinggan Range can be divided into two formations, i.e., felsic-dominant Fuminghe Formation and overlying mafic-dominant Ganhe Formation. The Dong'an gold deposit, a typical adularia–sericite epithermal system, is spatially closely associated with rhyolitic porphyry, which is a subvolcanic intrusion of the Fuminghe Formation. Total measured, indicated, and inferred resources for the Dong'an deposit are 70 tonnes (2.25 Moz) of gold with the grade of 5.04 g/t Au, making it one of the largest epithermal gold deposits in China.
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