Search

More than 50 earthquakes occurred in the Luding region, including a 6.8‐magnitude earthquake on September 5, 2022, which induced huge amounts of geological disasters. As the main triggered factors for the geological disasters, the vegetation, precipitation and temperature show regular changes on the time axis. Thus, this paper based on the spatial–temporal evolution of the precipitation, temperature and normalized difference vegetation index (NDVI), focuses on the susceptibility of the Luding area using the weighted information content method (ICM) and analytic hierarchy process (AHP) for the post‐earthquake regional planning and reconstruction. In the Luding area, it was found that there were 18 debris flow gullies, and 470 geological disasters scattered in the debris flow gullies. The NDVI of the study area has been declining in recent years, with only about 12% of the NDVI increasing from 2015 to 2020. From 2011 to 2015, the annual cumulative precipitation has been dropping overall, while the July average temperature has increasing quadratic functions after decreasing trend. Furthermore, the studied area's geological hazards susceptibility was classified into five categories, with extremely low susceptibility accounting for 5.82%, low susceptibility accounting for 13.61%, moderate susceptibility accounting for 38.54%, high susceptibility accounting for 39.96% and extremely high susceptibility accounting for 2.08%. The geological disasters in moderate, high and extremely high susceptibility accounted for approximately 95.08%, and the covered area of geological disasters in moderate, high and extremely high susceptibility accounted for 88.06%. Through the receiver operating characteristic (ROC) curve of the model verification found the AUC = 0.743. The geological hazards susceptibility study results show that the approach is useful for the analysis and prevention of geological disasters. [ABSTRACT FROM AUTHOR]

The Dunhuang Basin, situated in western China along the Altyn Tagh Fault (ATF) zone, intersects the Tethys and Paleo‐Asian Ocean tectonic domains. Influenced by both the ATF system and the far‐field effects of the Qiangtang‐Lhasa‐Eurasia collision during the Mesozoic, the mechanism of the Jurassic sedimentary migration of the basin in response to tectonic movements is unclear so far. The paper uses a comprehensive approach, including field geological surveys, lithologic and lithofacies discern, stratigraphic relationships analysis and 2D seismic profile interpretation, to examine the distribution of Jurassic residual strata in the basin. The comprehensive results of our study suggest that the Dunhuang Basin exists as an isolated block with unique tectonic and sedimentary evolution characteristics. In the Early Jurassic, the Dunhuang Basin underwent initial rifting, leading to the formation of small segmented intermontane sags. This phase was marked by the coarse particle sedimentary system of alluvial fans and braided rivers, represented the near source rapid deposition in the initial formation period of the basin. Stratigraphic distribution was primarily influenced by pre‐Jurassic basement topography and was not significantly constrained by faulting during this period. The formation of these isolated discontinuous small intermontane sags indicates the segmented activities of the ATF in the Early Jurassic period. In the Middle Jurassic period, influenced by the ATF dextral strike‐slip faulting, sedimentation extended eastward and the depocenter migrated clockwise compared with the distribution of the Middle Jurassic strata within the Dunhuang Basin. This period witnessed the development of coal measure strata at the basin's margins and lacustrine fine‐grained clastic deposition in the centre. The segmented fracture of the ATF gradually initiated a unified dextral strike‐slip tectonic movement. In the Late Jurassic period, sedimentary strata were locally present in the Wanyao Sag but absent in other sags. The depocenter migrated counterclockwise compared with the distribution of Middle Jurassic strata within the Dunhuang Basin, due to regional uplift accompanied by the ATF sinistral strike‐slip faulting caused by the collision between the Lhasa Block and the Eurasia Plate. The depocenter migration of the Dunhuang Basin constrained within the ATF system from the Early to Middle and Late Jurassic can be attributed to the transition of the ATF strike‐slip faulting in context of the stress relaxation and compression between the collision of the Qiangtang and Lhasa blocks to the Eurasia Plate, respectively. [ABSTRACT FROM AUTHOR]

Organic‐rich shale in saline lacustrine basins holds significant importance as a source rock for conventional hydrocarbon exploration and has emerged as a prominent target for unconventional hydrocarbon exploration and development in recent years. Based on saline lacustrine basins, this paper provides a summary of the organic matter enrichment mechanisms in saline lacustrine basins, considering sedimentary characteristics, biological activities, factors for the organic matter enrichment and consumption, and hydrocarbon generation. The implications for these factors are discussed in relation to the distribution prediction of high‐quality lacustrine shale district settings and the exploration and development of shale oil. Saline lacustrine basins undergo distinct evolutionary stages, each corresponding to different sedimentary stages involving carbonate minerals, sulphate minerals, and alkaline minerals. Moreover, these basins exhibit diverse biological types and experience extensive biological activities. The prosperity of organisms and the accumulation of sedimentary organic matter are ensured by halophilic organisms. Organic matter enrichment in saline lacustrine basins is influenced by two main aspects: the primary productivity of organic matter, which is promoted by the proliferation of halophilic organisms, and the efficient preservation of organic matter facilitated by the strong reducing environment resulting from promoted water salinity stratification. The organic matter consumption in saline lacustrine basins involves bacterial sulphate reduction (BSR) in the early stages, thermochemical sulphate reduction (TSR) in the late stages, and dilution of salt minerals with higher depositional rates. of the presence of salt beds and saline minerals positively influences hydrocarbon generation and expulsion in organic‐rich shale within saline lacustrine deposition. Consequently, continental saline lacustrine basins in China offer favourable conditions for the formation of organic‐rich shale and present broad prospects for the exploration of shale oil and gas resources. [ABSTRACT FROM AUTHOR]

This paper has conducted a high‐resolution characterization of a deeply buried carbonate karst in the Tarim Basin of China by utilizing the FMI (Full‐bore Formation Micro Image) method integrated with seismic data, drilling cores and thin sections. It was found that the type and scale of wellbore karst architecture are mainly controlled by karst paleogeomorphology and vertical faults. The karst highlands and slopes, respectively, develop vadose karst and phreatic karst, with different compositions of karst elements. In terms of the karst thickness in the wellbore, the vertical fault development zone is almost twice that of the non‐development zone, both for the vadose karst and phreatic karst. Furthermore, the vertical fault is also able to promote the development of mixing karst. The mixing zone is located 55 m below the water table, with a strata thickness of approximately 25 m, a net reservoir thickness of 5–15 m, and an average porosity of 4%–8%, which serves as an effective hydrocarbon reservoir in the Yingshan Formation. The results will provide insights into the vertical division of karst reservoir and help predict reservoirs using well logs. [ABSTRACT FROM AUTHOR]

Lithofacies and micropore characteristics of shale reservoir directly affect the exploration and development of natural gas. To determine the development potential of shales of the Longmaxi Formation in the Western Hunan‐Hubei Region, the lithofacies types and micropore structure characteristics of the Longmaxi Formation shales have been systematically studied in this paper, based on ordinary thin sections, argon ion polishing–scanning electron microscopy, physical property testing, x‐ray diffraction whole‐rock and clay mineral analysis, isothermal nitrogen, and carbon dioxide adsorptions. According to the principle of 'laminar structure + total organic carbon (TOC) + mineral composition of felsic, clay, and carbonate minerals', eight types of shale lithofacies were identified. The effective porosity of the Longmaxi shale ranges from 1.8% to 14.4%, with a peak range from 3% to 6%, while the permeability ranges from 0.001 to 1.27 mD, with an average of 0.106 mD. Combined with the isothermal adsorption experiments, the proportion of mesopores is the largest in the Longmaxi shale, followed by macropores and micropores. Moreover, the pore diameters of mesopores are concentrated between 3 and 10 nm, while those of micropores are concentrated between 0.4 and 0.9 nm. The pore volume of shale is most developed when the content of brittle felsic minerals is 50% ~ 75% and the content of clay minerals is 25% ~ 50%, and the TOC content is positively correlated with the pore volume and specific surface area. There are significant differences in the pore development characteristics of different lithofacies. The shale reservoir space analysis indicates that micropores are controlled by TOC content and clay minerals, while the macropores are controlled by depositional intergranular pores, TOC content, and felsic content, as well as diagenetic pyrite mould pores, microfractures pores, and intercrystalline pores. On the other hand, mesopores are related to a mix of depositional and diagenetic factors with dominant contribution of intergranular pores, intercrystalline pores, organic pores, and intergranular shrinkage fractures pores. It is found that the pore development of massive organic‐rich siliceous shale lithofacies has the best reservoir quality, including well‐connected intergranular pores, intercrystalline pores, organic pores, and shrinkage fractures. Therefore, the massive organic‐rich siliceous shale lithofacies is the dominant fine‐grained reservoir lithofacies in the studied area. Based on understating the pore characteristics of different lithofacies, this study can provide a scientific basis for the prediction of favourable sweet spots of shale gas reservoir in the Longmaxi Formation, western Hunan‐Hubei Region. [ABSTRACT FROM AUTHOR]

To investigate the impact of solar energy on the carbon footprint, to find effective measures to reduce the carbon footprint and slow global warming as soon as possible, this paper takes 30 provinces in China as an example. First, the inter‐regional input–output model is used to calculate the carbon footprint of each province. Then, the panel quantile regression model is used to investigate the impact of solar energy generation on different quantiles of carbon footprint. The results show that from 2012 to 2020, China's carbon footprint is at a high level, which is not conducive to the achievement of the goal of peaking carbon dioxide emissions. The eastern region has the highest carbon footprint, followed by the western region, the central region has the lowest carbon footprint, and its carbon footprint proportion continues to decline. The increase of solar energy generation can significantly reduce the carbon footprint of high quantile location, but has no significant impact on the carbon footprint of the middle and low quantile locations. Except for the negative impact of afforestation area on carbon footprint, the others control variables are all positive. Therefore, to reduce the carbon footprint of China, it is necessary to upgrade solar technology, increase solar energy generation, reduce energy consumption per unit of GDP (Gross Domestic Product) and the share of coal consumption, strengthen forestry management and reduce reliance on private vehicles. [ABSTRACT FROM AUTHOR]

The Chinese government's use of fiscal policy, which includes fiscal income and spending, is crucial in its fight against environmental pollution and climate change. Innovation‐driven has arisen as a new alternative to reconcile economic success with environmental conservation in light of tighter resource restrictions and the suggestion of the Chinese High‐quality Development policy. The paper uses an econometric model to examine the connection between institutional resource consumption efficiency and carbon neutrality, using a data set consisting of Chinese inter‐provincial panel data from 2007 to 2020 as a research sample; fiscal decentralization is also discussed as a potential moderating factor. Collaborative innovation positively boosts ecological efficiency and produces geographical spillovers, and the findings suggest so long as the economic distance is considered. When it comes to increasing ecological efficiency, collaborative innovation plays a more important role than financial decentralization alone. Among these is the improvement of carbon neutrality, which is best achieved via the joint promotion of ecological efficiency and industrial organizations. By reducing the intensity of the positive effect of innovative cooperation on ecological efficiency, the moderating effect suggests that fiscal decentralization is a critical factor in this relationship. Promoting China's ecological efficiency necessitates a fair distribution of local budgetary spending. China should also actively encourage the degree of synergy between institutional resource consumption efficiency and associated institutions to improve eco‐efficiency. [ABSTRACT FROM AUTHOR]

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

Landslides with step‐like deformation features are widely distributed in the Three Gorges Reservoir area (TGR) of China, posing a severe hazard to the inhabitants of this region. This paper proposes a multi‐input and multi‐output intelligent integrated displacement prediction model for landslides with step‐like displacement patterns. In this new model, three interconnected and information‐transmitted functional sub‐models are integrated. Unsupervised learning is used to identify different landslide deformation states automatically, and the imbalance classification and explainable artificial intelligence techniques are introduced for qualitative prediction and information filtering. Probability theory and deep machine learning are adopted to provide deterministically predicted values and quantify their uncertainty. The case study of the Baijiabao landslide in the TGR region proves that the proposed model performs satisfactorily in both point and interval predictions. The intelligent integrated model can also provide the forecast of landslide deformation states, visual input information filtering and back analysis of influencing factors, which are valuable to landslide early warning and risk management. [ABSTRACT FROM AUTHOR]

The Permian–Triassic boundary (PTB) volcanic tuffs are widely distributed in the East Palaeo‐Tethys region, but their age and origin have been controversial. The Permian–Triassic deep‐water sediments in the northeastern margin of South China are favourable research objects, and we report new results from the PTB deep basin sediments in the Susong area, Anhui Province, in this paper. Two volcanic tuffs are found in the Zuoshan PTB in the Zuoshan section, and Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) U–Pb zircon dating indicates that the upper and lower tuffs are 251.3 ± 1.7 Ma and 252.3 ± 2.1 Ma, respectively. The PTB age is 251.6 Ma according to a numerical interpolation method of the average deposition rate of the PTB. Fusulinids and non‐fusulinid foraminifers in the limestone overlying the lower tuff define the rock as end‐Permian. Zircon trace elements show that both tuffs are sourced from felsic volcanism in continental arc background, and their source magmas were derived from the continental crust. Zircons of PTB age from the upper tuff on the bottom of the Triassic have negative εHf(t) value from −8.02 to −3.75, and the Palaeo‐Mesoproterozoic two‐stage model ages of 1502–1780 Ma, showing that their source rocks were only derived from the remelting of the Palaeo‐Mesoproterozoic continental crust. The zircons from the lower tuff on the top of the Permian show two types, including negative εHf(t) values from −6.48 to −1.25 and Palaeo‐Mesoproterozoic two‐stage model ages of 1350–1679 Ma, and positive εHf(t) values from +3.98 to +10.15, and Neoproterozoic two‐stage model ages of 629–1023 Ma, indicating that their sources were derived from the reworking of the Palaeo‐Mesoproterozoic continental crust and early Neoproterozoic depleted mantle joined in juvenile crust growth in the northern margin of the South China Block at the beginning of the collision between the South China and North China blocks. The initial collision started no later than 252.3 Ma and developed significantly from east to west. [ABSTRACT FROM AUTHOR]

Challenges brought on by the rapid rate of economic growth include the depletion of natural resources (NAR) and environmental deterioration. Due to its abundant mineral resources and rapid economic growth, China has gained attention from both the developing and developed worlds. Using data from 1970/Q1 to 2020/Q4, this paper evaluates the time‐frequency nexus between CO2 emissions and natural resources, coal consumption, and economic growth. The study employs the Wavelet Local Multiple Correlation (WLMC) to explore this nexus. This approach enhances the capacity to comprehend the fundamental relationships between these indicators at different frequencies. To the best of the investigator' knowledge, this is the first empirical investigation to explore the time‐frequency nexus between natural resource, economic growth, coal use, and CO2 emissions in China, thus filling a gap in the literature. Furthermore, wavelet coherence is employed as a robustness check. The WLMC bivariate cases revealed that economic growth, coal consumption, and natural resources drive CO2 emissions positively at all frequencies, that is, in the short and long‐term, thus leading to environmental degradation. Furthermore, the wavelet coherence results support the outcomes of the WLMC bivariate cases. This study offers significant implications for policy and insights that are supported by the findings. [ABSTRACT FROM AUTHOR]

The tight sandstone reservoirs have become the focus of today's oil and gas exploration. To clarify the microscopic characteristics of the tight sandstone reservoirs of the Chang 63 deep water gravity flow origin in the Huaqing area, the Chang 63 gravity flow origin reservoirs in the study area are divided into three categories. They are the formation reservoir of sandy clastic flow (FROSF), formation reservoir of muddy debris flow deposits and turbidites (FROMT) and formation reservoir of slides and slumps (FROSS). In this study, core and logging data, thin sections, field emission scanning electron microscopy (FE‐SEM), and mercury intrusion capillary pressure (MICP) were combined to investigate the rock composition and pore‐throat characteristics of tight sandstone reservoirs with different types of gravity flow origins. The reservoir micro‐heterogeneity is also investigated in this paper. The results show that the reservoirs with different gravity flow origins are similar in lithology and are mainly composed of feldspar lithic sandstone and lithic feldspar sandstone. The pore types are mainly intergranular pores and feldspar‐dissolved pores. There are significant differences in the porosity, permeability, microscopic pore‐throat characteristics and microscopic heterogeneity of the reservoirs. From FROSF to FROMT and FROSS, the porosity, permeability, mercury inlet saturation, discharge pressure, median pressure and mercury removal efficiency gradually decrease. The tightness of the reservoir gradually increases. The storage capacity is gradually reduced. The disparity between the throat radius and pore radius gradually increases. The pore‐throat structure becomes more complex, and the microscopic heterogeneity of the reservoir gradually increases. [ABSTRACT FROM AUTHOR]

The Zhangguangcai Range is located in the junction zone of the Palaeo‐Asian and Palaeo‐Pacific tectonic regimes; Mesozoic igneous rocks in this area are considered to have been formed in an active continental margin, which is related to the western subduction of the Palaeo‐Pacific Plate beneath the Eurasian continent. However, the nature of the mantle wedge and related melting mechanism remains unclear. This paper reports zircon U–Pb data, whole‐rock geochemistry, and zircon Lu–Hf isotope for a Late‐Triassic high‐Mg andesite in the southern part of the Zhangguangcai Range. Zircons from the andesite yield a concordant 206Pb/238U age of 218.6 ± 3.3 Ma, which is contemporary with the diorite in the study area. The Lengshan high‐Mg andesite is characterized by moderate SiO2 (57.30–60.15 wt.%), high Mg# (61–67), Al2O3 (15.05–17.35 wt.%), (La/Yb)N (16.9–22.4), and variable Na2O/K2O (1.06–1.59). Its insignificant Eu negative anomalies (Eu/Eu* = 0.88–0.99) and high Sr/Y (68.4–96.4) may prove the existence of garnet or amphibole in the residual melt, where feldspar is more or less absent. The andesite is enriched in Rb, Ba and depleted in Nb, Ta, Ti, and other high‐field‐strength elements, with Nb/Ta ratios of 14.6–17.2, U/Th ratios of 0.28–0.31. In combination with its depleted zircon Lu–Hf isotopic compositions (e.g., εHf(t) = −0.48 to +13.1), it is proposed that the high‐Mg andesite formed by hydrous melting of the mantle wedge, which was metasomatized by slab‐derived adakitic melts. The subsequent assimilation of ancient crust results in the formation of some zircons with negative Eu*/Eu anomalies (0.05–0.1) and εHf(t) values (−13.8 to −18.5), which is approved by the relative evolved whole‐rock Sr–Nd isotopic compositions. [ABSTRACT FROM AUTHOR]

The Jiamusi‐Khanka Massif is an important tectonic unit of the Central Asian Orogenic Belt in North‐east China. Its Late Palaeozoic tectonic properties and the timing of assembly have restricted the understanding of the tectonic evolution process at the eastern segment of the Central Asian Orogenic Belt for a long time. Based on the study of clastic rock petrology and zircon U–Pb chronology of the Early Permian Erlongshan Formation in Mishan, it is clear that the zircon age of the Early Permian Erlongshan Formation in Mishan is mainly Late Palaeozoic, with a major age peak at 300 ± 3 Ma and secondary age peaks at 356 ± 7 Ma and 475 ± 10 Ma. The provenance mainly comes from the magmatic arc source area, and Early Palaeozoic (500–420 Ma) detrital zircons mainly come from the south‐east margin of Jiamusi Massif, Late Palaeozoic (400–270 Ma) detrital zircons mainly come from the eastern margin of Jiamusi Massif and the northern margin of Khanka Massif. Among them, detrital zircons of a special age group 330–310 Ma come from the north of Khanka Massif, while 490–470 Ma detrital zircons which are common in the Early‐Middle Permian strata of Khanka Massif come from Jiamusi Massif. Combined with the evidence of petrology and palaeontology, this paper believes that the Early Permian Jiamusi Massif and Khanka Massif should be a unified Massif, that is, Jiamusi‐Khanka Massif. [ABSTRACT FROM AUTHOR]

Understanding the interrelationship between diagenesis and hydrocarbon emplacement is crucially important for investigating tight sandstone reservoir‐forming processes. In this paper, efforts were made to elucidate this interrelationship in the Jurassic Badaowan Formation tight sandstone reservoirs of the southern margin of the Junggar Basin (SJB), China. Four lithofacies were clarified, including quartz cemented‐dissolution facies (QCDF), carbonate cemented facies (CCF), authigenic clay mineral facies (ACMF), and matrix‐caused tightly compacted facies (MCTF). Weak hydrocarbon migration forces and poor hydrocarbon preservation conditions were identified to be the main reasons for the limited hydrocarbon accumulation scale. The reservoir densification process, mostly before 100 Ma, was associated with four aspects, including the high matrix content, the intensive carbonate cementation, the limited dissolution and alteration, and the development of authigenic clay minerals. Hydrocarbons in the Badaowan Formation reservoir were demonstrated to be emplaced after reservoir densification. Overpressure resulting from hydrocarbon expulsion and tectonic compression should have acted as the main driver for hydrocarbon migration. Particularly, the tight sandstone in the Qigu anticline was charged with overpressurized hydrocarbons sourced from the middle‐lower Jurassic source rocks at the footwall of the Qigu north fault since the early Jurassic. The tectonic compression in the late Neogene eroded the core of the Qigu anticline, which destroyed the initially large palaeo‐oil reservoir into smaller ones. The first‐stage hydrocarbon emplacement greatly affected the diagenesis and physical properties of the reservoir. It played an important role in inhibiting cementation, promoting dissolution, and altering the petrophysical properties of the tight sandstone reservoir. The densification process controlled the wettability and capillary pressure of pores in the tight sandstone. Specifically, the high kaolinite cement raised the hydrophilia, while the ubiquitous densification increased the capillary pressure of pores. [ABSTRACT FROM AUTHOR]

Well SK‐2 is located in the Songliao Basin. Core samples from this well indicate that the Early Cretaceous Shahezi Formation has a length of 2,359.01 m and is in direct contact with the basin basement of the Middle Triassic, missing the Huoshiling Formation. This paper is focused on the lowest sequence 1 (S1, at the bottom of the Shahezi Formation, interval of 5,450.72–5,695.00 m, a length of 244.28 m) of the Cretaceous basin fills. It was found that the volcanic components contributed important parts in the sequence of basin fills, and the start of the rifting resulted from the combination of regional extensional tectonics and volcanism. Based on the centimetre‐scale description of the continuous core samples, we propose a model to delineate the interaction between tectonics, volcanism, and pyroclastic deposition. The study shows the tectonic‐volcanism in the earliest rifting stages and its control on sedimentary filling. These results also have common sense for the initial rifting process of a continental half‐graben basin. Sequence 1 of the Shahezi Formation in well SK‐2 shows a typical volcanic‐ sedimentary sequence. During the lowstand stage, the weathering‐depositional system was controlled by extension; during the transgressive and highstand stages, the transitional weathering‐depositional system and the mixed volcanic and weathering depositional system were controlled by transtension. [ABSTRACT FROM AUTHOR]

Late Mesozoic granites are present throughout the Jiaodong Peninsula in eastern China, but the petrogenesis of these granites, the magma sources, and the geodynamic setting of the magmatism remain unclear. This paper presents new zircon U–Pb geochronological and Lu–Hf isotopic and whole‐rock geochemical data for the Late Jurassic Queshan pluton in the Shandong Peninsula, an area that represents the boundary between the Jiaobei and Sulu ultrahigh‐pressure (UHP) terranes. Laser ablation–inductively coupled plasma–mass spectrometry zircon U–Pb dating yields Late Jurassic ages from 158 ± 1 to 153 ± 1 Ma for the pluton in addition to a small number of inherited zircons that yield ages that cluster at 2410, 1831–1776, 750, and 209–202 Ma. Zircons from different samples have similar 176Hf/177Hf values (0.281926–0.282255) and variably negative εHf (t) values that range from −26.5 to −15.1 (weighted mean of −22.9 ± 0.9). The corresponding two‐stage Hf model ages range from 2,869 to 2,154 Ma, with a weighted mean value of 2,645 ± 54 Ma. These data indicate that the magmas that formed the Queshan pluton were derived from multiple sources, including the lower crust of the North China (NCC) and Yangtze (YC) cratons, as well as collision‐related alkaline rocks. The whole‐rock geochemical compositions of the samples indicate that the granites are weakly peraluminous, are high‐K and calc‐alkaline with I‐type affinities, and have high contents of Sr, low contents of Y and Yb, high (La/Yb)N and Sr/Y values, and positive Eu anomalies (δEu = 1.20–1.65), indicating an adakitic affinity. This indicates that the Queshan granites formed from magmas generated by partial melting of a thickened region of the crust (>50 km) associated with eclogite, garnet amphibolite, or amphibolite residual material. The genesis of the Late Jurassic granites are also likely to have been influenced by the collisional orogeny between the NCC and YC and continued subduction of the Izanagi Plate. Thickening of the lower crust associated with this continental collisional event occurred before the magmatism, with further compression and thickening of the lower crust caused by the low‐angle subduction of the Izanagi Plate beneath northeastern China being the main geodynamic driver of the formation of the granites in this region. [ABSTRACT FROM AUTHOR]

Hainan Island is a key part of the eastern Tethyan region and contains detailed geological information that can enhance our understanding of the tectonic evolution of this region since the late Palaeozoic. In this paper, we report geochronological, geochemical, and Sr–Nd isotopic data for granitoids from Baomei and Chahe in the northern part of Hainan Island. Three new zircon U–Pb ages of 243.3 ± 1.7 Ma, 237.1 ± 5.1 Ma, and 257.0 ± 4.0 Ma were obtained for these granitoids. The late Permian Chahe granite (257 Ma) is weakly peraluminous to peraluminous, and has rare earth element patterns and Ga/Al and FeOT/MgO ratios typical of A‐type granites formed in an extensional tectonic setting. The Middle Triassic Baomei granitoids (243–237 Ma) are weakly peraluminous, and exhibit a negative correlation between P2O5 and SiO2, which is typical of I‐type granites. All the granitoids have EM II‐type‐enriched mantle Sr–Nd isotopic compositions, which indicate that they were derived from a mantle source that had experienced enrichment and metasomatism. Hainan Island was in an extensional tectonic setting from the late Permian to Middle Triassic when widespread A‐ and I‐type granites were generated. We speculate that Hainan Island was mainly affected by the Tethyan tectonic domain during the Permian–Triassic, which involved closure of the Palaeo‐Tethys Ocean, collision of the Indochina and South China blocks, and subsequent post‐collisional extension. [ABSTRACT FROM AUTHOR]

This special issue is on active tectonics and palaeeo‐enviroment in West China. It comprises 19 original research papers under the following three themes: (a) Late Cenozoic intracontinental deformation in West China, especially in the northeast and north margins of the Tibetan Plateau (nine papers), (b) Geomorphic evolution (four papers), and (c) Palaeo‐environmental evolution and Cenozoic strata (six papers). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Kelameili Ocean was one branch of the Palaeo‐Asian Ocean, the initiation and closure history of which remains elusive. Consequently, they hamper our understanding of the accretionary evolution of the southern Altaids. In this paper, we carried out field mapping and also geochronological and geochemical analyses on the Huangcaopo Group in the northern Harlik Mountains, NW China. Field investigation revealed that "block‐in‐matrix" structure develops with blocks of andesite, limestone, sandstone, and gabbro in matrices of turbidites. Combined with our recent work, our field investigation indicates that the Huangcaopo Group is the southern extension of the Kelameili accretionary complex. A gabbro block (19HAM057) was dated at 500 ± 4 Ma, its geochemical affinity was defined to be similar to arc magmatic rocks. Magmatisms represented by two gabbroic intrusions (19HAM057‐2 and 19HAM048) were dated at the latest Devonian (360 ± 5 Ma) and the latest Carboniferous (299 ± 4 Ma), respectively. Their geochemistry displays enrichments in light rare earth elements (LREE) and large ion lithophile elements (LILE), but depletions in high field strength elements (HFSE, especially Nb and Ta). And a younger gabbroic intrusion (19HAM052) yielded crystallization age of the latest Permian (254 ± 3 Ma), and its geochemistry also shows affinity to arc magmatism. The magmatism represented by the gabbro block (19HAM057) was coeval with the Zhaheba‐Aermantai ophiolite, indicating that it was the product of incipient arc magmatism following subduction initiation in the Kelameili branch of the Palaeo‐Asian Ocean. However, two episodes of gabbroic magmas (19HAM057‐2 and 19HAM048) that intruded the Kelameili accretionary complex from the latest Devonian to latest Carboniferous indicate southward rollback of the subducting Kelameili oceanic lithosphere and resulted in the development of a growing arc. Meanwhile, the youngest gabbroic intrusion (19HAM052) suggests that northward subduction of the Kelameili oceanic lithosphere may have at least lasted to the latest Permian, indicating that the closure of the Kelameili Ocean might have been later than the latest Permian, most likely in the early Triassic. Our new data provide further constraints on the initiation and closure history of the Kelameili Ocean, which shed light on the accretionary evolution of the Altaids. [ABSTRACT FROM AUTHOR]

As one of the pioneer palaeontologists, Professor Zhuoting Liao has contributed his lifetime to promoting palaeontological and stratigraphical research in China for 60 years, and he passed away in the field excursion in South China on June 20, 2020. In his palaeontological career, Liao has worked on Late Palaeozoic to Mesozoic palaeontology and stratigraphy of almost all regions across China, and his interests have also extended to the Permian–Triassic (P‐Tr) boundary and mass extinction. He has worked on palaeontology, palaeobiogeography, biostratigraphy, tectonostratigraphy, and their implications in mineral and oil‐gas industries. Liao has established 22 new genera and 172 new species of brachiopods, and, together with his colleagues, proposed 11 new genera and 25 new species of echinoderms. He dedicated his lifetime to work on Late Palaeozoic palaeontology and stratigraphy of the previously remote and tectonically complex Xinjiang and adjacent regions, north‐west China, and established integrated stratigraphical frameworks for the Carboniferous to Permian strata, providing fundamental basis for mineral and hydrocarbon exploration in the poorly understood Central Asian terranes. In addition, he has mentored many young palaeontologists and stratigraphers in various ways. This volume assembles 30 papers addressing the Late Palaeozoic to Mesozoic palaeontology and stratigraphy of China and adjacent regions, which pays tribute to the achievement of Professor Zhuoting Liao. [ABSTRACT FROM AUTHOR]

Cone‐producing gymnosperms are important elements of the Mesozoic floras. Studying their cone organizations can potentially help us understand the evolutionary trends of seed plants through time and the origin of angiosperms. In this paper, we present a new and an undetermined species of Ixostrobus Raciborski, a fossil genus representing male cones of the Czekanowskiales from the Middle Jurassic Daohugou locality in Inner Mongolia, China. The holotype specimen of the new species was studied using the neutron tomography (NT) technique. The cone shows higher neutron attenuation than the surrounding matrix. To detect the different organic compounds, a volume rendering of tomographic reconstruction with false colour spectrum of relative neutron attenuation is presented. The highest concentration of organic material is in the axis and some parts of the sacs, the rest of the cone has lower concentration, and the surrounding matrix has the lowest concentration. It seems that the remnant organic materials are regularly differentiated in different parts of the cone probably because of the preservation and different taphonomic process of different type of cells. In addition to revealing more detailed morphological features of the cone by NT reconstruction, the application of NT is potentially important for detecting remnant organic materials preserved in fossil plants. [ABSTRACT FROM AUTHOR]

The Central Asian Orogenic Belt (CAOB) is one of the largest accretionary orogenic collages in the world with prominent juvenile crust addition, where the southernmost margin of the CAOB located is one hot topic in the international studies. The Dunhuang Block located to the south of the Beishan Orogen is a key position for outlining the tectonic framework of the south margin of the CAOB. However, at present, the tectonic attribution of the Dunhuang Block is still controversial. In this paper, we focus on the origins and protoliths of the meta‐mafic rocks from the Hongliuxia complex in the southern Dunhuang Block for determining the tectonic attribution of the Dunhuang Block. In the field, the meta‐mafic rocks are mainly exposed as tectonic blocks within the metasedimentary rocks displaying the "block‐in‐matrix" fabrics or as tectonic slices juxtaposed by faults. Geochemically, the meta‐mafic rocks could be divided into three groups based on the rare earth elements (REE) and trace elements: the group 1 samples are depleted in the LREE relative to HREE and show flat HREE patterns, similar to the mid‐oceanic ridge basalt; the group 2 samples show flat REE patterns without obvious differentiation between the LREE and HREE, like the oceanic plateau basalt; the group 3 samples are enriched in LREE relative to LREE, and have negative Nb, Ta, and Ti anomalies, similar to the island arc basalt. Conclusively, the protoliths of the meta‐mafic rocks dominantly belong to the oceanic plate components. They were metamorphosed during Early Silurian to Middle Devonian in different depths of the subduction zone documented in previous studies. So, we suggest the Hongliuxia complex is an exhumed Palaeozoic subduction–accretion complex (SAC) formed during the oceanic plate subduction. This result confirms the Palaeozoic subduction event occurred in the Dunhuang region and indicates that the Dunhuang Block is a Palaeozoic Orogen rather than a part of Precambrian continent block. Considering the regional geology context, we speculate the Dunhuang Orogen belongs to the southernmost margin of the CAOB. [ABSTRACT FROM AUTHOR]

The terrestrial sequence stratigraphy in proximal terrestrial environments is different from its counterpart in distal terrestrial and marine environments. The Southern Junggar Basin in NW China has preserved well‐exposed proximal terrestrial outcrops and its Jurassic–Cretaceous sequence boundary remains contentious. The goal of this paper is to (a) establish a model of allogenic‐controlling mechanisms of a proximal terrestrial sequence, (b) investigate the Jurassic–Cretaceous sequence boundary, (c) the Jurassic climate, and (d) tectonic movements in Central Asia. The sequence stratigraphic framework was established assisted by the determination of the accommodation space/sediment supply (A/S) ratio, including two second‐order sequences (SS) and six third‐order sequences (SQ) in the Jurassic, as well as a second‐order sequence in the Cretaceous. SS1 was mainly controlled by a warm and humid climate and lake level fluctuations in a weak extensional tectonic setting; SS2 was mainly controlled by an arid climate and compressional tectonic movements; SS3 was mainly controlled by a semi‐humid climate and lake transgression in a stable tectonic setting. Additionally, the Jurassic–Cretaceous sequence boundary was distinguished within the Kalazha Formation based on its sedimentary characteristics, sedimentary evolution, and different allogenic controls. It is concluded that the proximal terrestrial sequences exhibit rapid sedimentary facies change, thick coarse‐grained sediments, and multiple provenances. Climate, tectonic movements, and lake level fluctuation dominate in different stages of basin evolution. Moreover, the sediment supply is more emphasized, and the accommodation space/sediment supply ratio, which corresponds to different channel geometry types, plays a critical role in identifying system tracts and sequence stratigraphic surfaces. [ABSTRACT FROM AUTHOR]

The marginal area of a sedimentary basin is closer to the provenance, so the sand body is generally more developed. For the Western Margin Thrust Belt of the Ordos Basin, the quality of the Jurassic sandstone reservoirs is still less studied. Diagenesis and reservoir evaluation are important research contents and hotspots in sedimentary geology. Therefore, in this paper, the diagenesis and reservoir properties of the Jurassic Yan 6 to Yan 10 members (Yan'an Formation) have been systematically studied based on the latest 3D seismic, well logging, cast thin section, scanning electron microscope and petrophysical property tests in this area. Furthermore, the vertical heterogeneity of petrophysical properties of the Jurassic reservoir has been discussed in detail, and the diagenetic evolution sequence and classification criteria of Jurassic sandstone reservoir have been proposed. The research results show that the lithologies of the Yan 6 to Yan 10 members are mainly lithic quartz sandstone, lithic feldspar sandstone and feldspar lithic sandstone. The pore types of sandstone are mainly intergranular pores, followed by dissolution pores, intercrystalline pores and a few microfractures. There are two high‐value porosity zones in the buried depths of 1,950–2,050 m and 2,150–2,250 m, which are the coupling results of dissolution and palaeo‐overpressure. Based on the comprehensive study of petrology, petrophysical properties and diagenesis, the diagenetic evolution sequence of the Jurassic sandstone was restored and a comprehensive classification standard for the Jurassic sandstone reservoirs is proposed. The Jurassic reservoir in the study area is a structural‐lithological reservoir, which has a unified oil–water interface, the Type I and Type II reservoir areas in the structural high positions are conducive to the large‐scale accumulation of hydrocarbons. [ABSTRACT FROM AUTHOR]

To study the status quo of research on geological hazards in the Central China Orogen and its geological distribution quantitatively, we used bibliometric methods and deeply analysed the numbers, the authors and research institutions involved, and the distribution and changes of the research contents of papers on geological hazards published from 1962 to 2016. This review involved 26,677 documents, 26,339 authors, and 11,095 research institutions. The results showed that the study of geological hazards has significant time‐domain characteristics. In this field, the greatest number of papers was published in Recent Developments in World Seismology and the Chinese Journal of Geophysics–Chinese Edition, with 456 and 159 papers, respectively. As shown by an analysis of keywords, the current research focuses mainly on the evaluation, distribution characteristics, development regularity, detection and prediction, and prevention and control of geological hazards. The conclusions find that the authors of foreign‐published papers are mostly Chinese researchers, which cannot reflect the status quo of foreign research in this field to a certain extent. Differentiation between domestic and foreign research approaches and objectives through comparative analysis should be further explored. [ABSTRACT FROM AUTHOR]

The solar radiation or insolation at a specific locality on the Earth's surface is determined by the distance of this point from the sun and by the angle with which the radiation hits the earth's surface. The theory that variations in the earth's orbit determine the amount of radiation and therefore the climate which is the Milankovitch Cycle. In non‐marine lacustrine rift basin, the changes of climate can be recorded by the palaeontology, and it also plays an important role in controlling lacustrine fluctuations. The lacustrine fluctuations are indicated by coastal onlap, which is the landward or lake‐ward onlap of non‐marine coastal deposits. In this paper, based on borehole data, wireline logs, seismic datasets, biostratigraphic data and palaeontology, the lacustrine fluctuation curve can be reconstructed from the onlap of lacustrine deposits in non‐marine sequences. The durations and magnitudes of these changes can be used to construct charts showing cycles of the relative rising and falling of lake level. In addition, the changes of lake level can also be reflected by the palaeontology such as pollen. The living conditions and distributions of pollen can be a good indicator for climate changes and lacustrine fluctuations in an a non‐marine setting. The calculation of the Milankovitch Cycle can be determined by the GR log in the study area which keeps a record of cycle changes. All climatic changes and lacustrine fluctuations are mainly resulted from the Milankovitch Cycles, and therefore, through the reconstruction of lacustrine fluctuations, climate changes and the Milankovitch Cycle, the correspondences among them can be clearly addressed. All the results can contribute a lot in theory research in the study area and lead to a new focus in practical hydrocarbon exploration and exploitation. [ABSTRACT FROM AUTHOR]

Devonian is a critical period for reversal of arc polarity and transition of continental margins from passive to active settings in the northern margin of the North China Block (NCB). However, the evolution processes during this period are still poorly constrained due to limited distributions of Devonian magmatism and sedimentary records in the NCB. In this paper, we present new zircon U–Pb geochronological, whole‐rock geochemical and Sr–Nd–Hf isotopic data of some recently identified Devonian volcanic rocks from the Jiefangyingzi area in the northeastern margin of the NCB. The Jiefangyingzi volcanic rocks display a bimodal composition and consist predominantly of amphibolite (meta‐basaltic andesite) and meta‐rhyolite and rhyolitic tuff with minor meta‐andesite. New SHRIMP and LA‐ICP‐MS zircon U–Pb dating results show that the volcanic rocks erupted during the early‐middle Devonian period (397–389 Ma). Geochemical and Sr–Nd–Hf isotopic data indicate that the mafic‐intermediate components were mainly derived from an enriched lithospheric mantle source, and the parental magma experienced fractional crystallization during magma ascent. The felsic rocks were mainly originated by partial melting of ancient lower continental crust, with mixing of some mantle‐derived mafic magmas. The occurrence of Devonian bimodal volcanic rocks, combined with the Devonian alkaline magmatic belt, suggesting that the northern margin of the NCB was a post‐collisional extension environment during the early‐middle Devonian period. In addition, the Sr–Nd–Hf isotopic results of the Devonian felsic volcanic rocks suggest that the Jiefangyingzi area is located in the North China Craton (NCC) rather than the Bainaimiao arc belt, and the orogen‐craton boundary between the northern NCC and Central Asian Orogenic Belt (CAOB) is located in some areas north to the Jiefangyingzi area. [ABSTRACT FROM AUTHOR]

Yang et al., Acta Geologica Sinica‐English Edition, 91(2), pp. 749–750 claim that they discovered supercritical hyperpycnal flow deposits in the Early Cretaceous strata on Lingshan Island, East China. We would like to discuss this paper under the following topics: (a) the terminology of "supercritical hyperpycnal flow," (b) hyperpycnal flow deposition, and (c) supercritical flow deposition. Our aim is twofold in that the following debate will help unravel the complexities associated with the controversy around the paleosedimentary environment and sediment dynamic processes of the early Cretaceous deposits on Lingshan Island, in addition to providing an understanding of hyperpycnal flow and supercritical flow deposits. The Beilaishi section deposits on Lingshan Island are more likely storm‐induced tempestites within the lacustrine basin delta front and associated deep lacustrine turbidites. Frequent earthquakes due to tectonic‐magmatic activity are the most likely triggers for lacustrine storms. [ABSTRACT FROM AUTHOR]

The Yinggen‐Ejinaqi Basin (YEB) is located in the central‐southern part of the Central Asian Orogenic Belt (CAOB). Tectonically, the basin is situated at the intersection between the eastern and western CAOB, where Late Palaeozoic strata were well exposed. Hence, it offers a great opportunity to study the deep strata of the eastern CAOB. In this paper, based on extensive studies of Upper Palaeozoic field outcrops and reanalysis of associated geochemical and geochronological data in previous research, the local stratigraphic correlation is established, and the tectonic evolution, sedimentary filling, sedimentary characteristics, and petroleum system of the YEB are discussed. It is revealed that: (a) The filling characteristics of the Upper Palaeozoic strata in YEB are closely related to the closure of the Paleo‐Asian Ocean (PAO). YEB underwent subduction‐related compression during the initial extensional phase of the fore‐arc basin from the Viséan to the Serpukhovian (late Early Carboniferous). During the Bashkirian–Sakmarian interval (Late Carboniferous to Early Permian), it was in subduction‐related fore‐arc and postarc rifting phases. During the Artinskian–Capitanian (Early‐Middle Permian) times, it was in an intracontinental rifting‐depression phase. During the Wuchapingian (Late Permian), it was in an intracontinental compressional phase. Tectonostratigraphy, tectonic evolution, and hydrocarbon potential assessments of the study area show that the Zhusileng Hangwula‐Tost Ul tectonic zone (ZHTUTZ) and southwestern part of Querrshan‐Atasbogd tectonic zone (QATZ) are identified as the main prospective areas for the exploration in the YEB. (b) According to the tectonostratigraphic analysis, tectonic evolution and hydrocarbon system of Carboniferous–Permian in the YEB, the YEB has similar attributes to the basin province in western CAOB (e.g., Santanghu and Junggar basins) and eastern CAOB (Erlian, Songliao Basin). To explore commercial oil and gas in the deeper strata (Carboniferous–Permian) of the eastern CAOB basins, further tectonostratigraphic analyses and comprehensive assessment on hydrocarbon potentials are necessitated in the near future. [ABSTRACT FROM AUTHOR]

The Junggar Basin is one of the main oil basins in Northwest China, and the north‐west part of the basin is a significant petroleum exploration target. Mesozoic structural activity had an important influence on the present structural characteristics of the north‐west Junggar Basin. In this paper, we discuss the tectonic evolution of the Junggar Basin by studying the structural characteristics of the Ke‐Bai Fault. Our results suggest that the Ke‐Bai Fault has obvious strike‐slip characteristics and that it is an important basin‐controlling fault that has controlled the tectonic evolution of the north‐west Junggar Basin. The Junggar Basin was a rift basin in the Early Permian, but it experienced a tectonic reversal during the Middle Permian to the Triassic. The Ke‐Bai Fault changed from a normal fault into a thrust fault from the Early Permian to the Triassic. During the Jurassic, dextral strike‐slip structures developed along the Ke‐Bai Fault, horsetail splay faults developed in its north segment, and there is evidence that it was under WNW–ESE compression. The dextral strike‐slip faulting of the Ke‐Bai Fault is consistent with tectonic movement along the Kelameili, Sangequan, Wu‐Xia, Hong‐Che, and North Tianshan fault systems in the Junggar Basin. We therefore infer that counterclockwise rotation occurred in the Junggar Basin in the Jurassic. [ABSTRACT FROM AUTHOR]

Abnormal pressure is considered significant for the migration and accumulation of oil and gas. The purpose of this study is to present the lateral and vertical distribution of underpressure conditions in the Huimin Depression determined using the drill stem tests (DSTs) and the well log data. This paper also provides the origins of the underpressure both qualitatively and quantitatively, as well as the effects of the underpressure on the distribution of hydrocarbons. The results show two vertical underpressure units at depths of 1,500–2,500 m and 3,000–4,000 m with a pressure coefficient of 0.8–0.95. Laterally, the underpressure is mainly distributed in the Northern Tectonic Uplift Belt (NTUB) and Southern Slope Belt (SSB). The rock dilation and temperature reduction caused the pressure reductions of 3–4 and 1–3 MPa, respectively. The diffusion of natural gas plays a limited role on the underpressure. An analysis of the lateral seals of faults indicates that the underpressured regions developed in areas with faults with shale gouge ratio (SGR) values larger than 0.6. We propose that the widely distributed underpressure in the Huimin Depression is related to rock dilation, temperature reduction, and fault sealing. An analysis of hydrocarbon migration and reservoirs showed the pumping effect provided by the deficient pressure could make underpressured regions the primary targets for hydrocarbon accumulation, and in the Huimin Depression, underpressure might be more important than overpressure. [ABSTRACT FROM AUTHOR]

Natural fractures not only improve the physical properties of shale reservoirs but also promote the formation of hydraulic fracturing networks. The accurate identification of natural fractures in shale reservoirs is of a great significance to the exploration and development of shale gas. In this paper, the Lower Cambrian Niutitang Formation in Cen'gong block of northern Guizhou Province is taken as the research horizon. A variety of conventional logging parameters are selected to identify the natural fractures in the Niutitang Formation of three shale gas wells in the study area by combining R/S analysis method. Fracture locations can be accurately determined by calculating the second derivatives of lg(R/S) function. Considering the sensitivity of logging parameters to natural fractures, the analytic hierarchy process (AHP) is used to assign the corresponding weight to each logging parameter. A new parameter, fracture development coefficient, is introduced to quantitatively characterize the development degree of natural fractures. The results of R/S analysis are compared with those of core fracture observation and statistics. The results show that R/S analysis has a good effect on shale fracture identification, and the effect of fracture identification of three wells presents the following order: TM‐1 > TX‐1 > CY‐1. There is a positive correlation between fracture development coefficient and fracture linear density, indicating that the larger the fracture development coefficient is, the more developed the shale fractures are. Therefore, the fracture development coefficient can be used to characterize the degree of fracture development. In addition, we also analyze the errors of the identification results of R/S analysis and compare this method with conventional logging method. R/S analysis based on conventional logging is an accurate and efficient fracture identification method, which provides a new idea for the study and quantitative characterization of the natural fractures in shale reservoirs. [ABSTRACT FROM AUTHOR]

Significant sedimentary and tectonic information is preserved in the geochemical characteristics of the Middle Triassic Zhifang Formation in the southern Ordos Basin, North China. In this paper, elemental geochemical analysis is performed for 12 mudstone and siltstone samples from the Zhifang Formation of the Liangzhai River–Liulinchuan section of Tongchuan City, Shaanxi Province, with a major element analysis performed via X‐ray fluorescence spectrometry, trace element and rare earth element (REE) analyses performed via inductively coupled plasma mass spectrometry (ICP‐MS). The palaeoenvironment and tectonic backgrounds of the study section are also studied by analyzing the elements and elemental ratios sensitive to palaeoenvironmental conditions. The geochemical proxies, including the concentrations of U, and ratios of Fe2O3/FeO, U/Th, V/(V + Ni), V/Cr, and Ni/Co indicate that the depositional environment of the Zhifang Formation was likely an oxic–dysoxic condition without strong lake‐water stratification. The oxic–dysoxic condition is interpreted as one of the key controlling factors for the poor development of source rocks in the Zhifang Formation, although this formation is dominated by black fine‐grained sediments. Because of the Qinling orogenic belt, the geochemical characteristics reflect a tectonic background of the provenance area that was an active continental margin related to the continental island arc. [ABSTRACT FROM AUTHOR]

This paper reports in situ U–Pb ages and Hf isotopic data on detrital zircons from Palaeozoic strata in central‐eastern Jilin Province, NE China, with the aim of constraining the timing of final closure of the Paleo‐Asian Ocean and the tectonic evolution of the eastern segment of the Central Asian Orogenic Belt (CAOB). Zircons from Middle to Late Permian Fanjiatun and Yangjiagou formations in central Jilin Province are characterized by four major groups of age populations (2.5–2.3 Ga, 1.9–1.7 Ga, 1.3–1.0 Ga, and Late Palaeozoic ages). The Paleo‐Mesoproterozoic and Cambrian zircons have positive εHf(t) values, suggesting that the source was mainly locally derived from the CAOB, whereas a lesser amount of Archean zircons with positive εHf(t) values, indicating that source from the North China Craton (NCC). The Phanerozoic zircons have both positive and negative εHf(t) values indicates that material from bidirectional provenances in the CAOB and the NCC. However, Late Permian Kaishantun Formation in eastern Jilin Province contain a single group of Phanerozoic zircons with positive εHf(t) values, distinct from known igneous zircons in the NCC, suggesting a local source. These observations, along with the results of previous studies on Middle–Late Permian igneous rocks in Jilin Province, indicate that the eastern segment of the Paleo‐Asian Ocean underwent the initial closure in central Jilin Province during the Middle Permian and the final closure in eastern Jilin Province in the Late Permian–Early Triassic. The detrital zircon geochronological data clearly record two stages of tectonic evolution and the scissor‐like closure model of the Paleo‐Asian Ocean in the eastern segment of the CAOB. [ABSTRACT FROM AUTHOR]

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

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

The Devonian volcanic rocks are widely distributed in the East Junggar (Xinjiang, NW China), preserving important magmatic records for investigating Palaeozoic tectonic evolution. The Beitashan Formation is mainly composed of pyroclastic rocks and sedimentary rocks in the lower section and intermediate–basic volcanic lava and pyroclastic rocks in the upper section. In this paper, we present geochronological, geochemical, and in situ Lu–Hf isotopic data for Beitashan Formation volcanic rocks from the East Junggar. Zircon U–Pb analyses from a basalt sample by laser ablation inductively coupled plasma mass spectrometry yielded a weighted mean age of 387.8 ± 4.5 Ma, indicating that it was generated in the Middle Devonian. The basic–intermediate volcanic rocks are tholeiitic to calc‐alkalic and are characterized by MgO (2.29–5.91 wt.%), low TiO2 (0.75–1.36 wt.%), and relatively high Al2O3 (15.82–16.73 wt.%). Furthermore, they display enrichment in light rare‐earth elements and large‐ion lithophile elements (such as Ba and Sr) and depletion in Nb, Ta, and Ti, along with slightly positive Eu anomalies (δEu = 0.83–1.15) and Ce anomalies (δCe = 1.00–1.11). In addition, in situ zircon Hf isotopic analyses from basalt samples show εHf(t) values ranging from +4.33 to +15.2, indicating a depleted mantle source with minor crustal contamination. They also show relatively low Nb/Zr (0.04–0.06), Th/Yb (0.67–3.83), and Ba/La (6.79–67.53) and high Ce/Th (7.71–18.94), Ba/Rb (21.39–294.28), and Ba/Th (31.42–486.58). The geochemical data suggest these rocks were likely derived from 10% to 30% partial melting of a garnet‐rich with minor spinel‐bearing Iherzolite depleted mantle metasomatized by slab‐derived fluids, with crustal contamination. Combined with the geological setting and previous studies, we suggest that the northern East Junggar was in a northward‐subducted island‐arc setting in the Devonian. [ABSTRACT FROM AUTHOR]

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

This paper presents new zircon U–Pb ages and Hf isotope data, and whole‐rock major and trace element geochemical data of Permian igneous rocks from the eastern Songnen Massif (SM) and the western Jiamusi Massif (JM), NE China, to constrain their tectonic evolution. Zircon U–Pb dating indicates that Permian magmatism within the eastern SM can be subdivided into two stages: early Permian (ca. 293 Ma) and middle to late Permian (272–257 Ma). The early Permian igneous rocks comprise a bimodal association of rhyolites, basaltic andesites, and gabbros. The middle to late Permian igneous rocks are dominated by gabbro–diorites, monzodiorites, quartz diorites, monzonites, quartz monzonites, granodiorites, monzogranites, syenogranites, and alkali feldspar granites, along with minor bodies of A‐type quartz trachytes. The Permian felsic magmas originated mainly from partial melting of a relatively juvenile lower crust, whereas the coeval mafic rocks were probably derived from partial melting of a relatively depleted lithospheric mantle that was modified by fossil subduction‐related fluids. The igneous rock associations and their geochemical features, together with data from coeval sedimentary and volcanosedimentary successions, indicate that Permian magmatism within the eastern Songnen and western Jiamusi massifs formed in an extensional environment, similar to a back‐arc setting, related to westward subduction of a Palaeo‐oceanic plate beneath the eastern margin of the Jiamusi Massif. We find no evidence for double‐sided subduction of the Mudanjiang oceanic plate during the Permian. [ABSTRACT FROM AUTHOR]

China is facing many challenges in the area of high‐precision exploration for deep mineral resources, and also in environmental and engineering fields. It has become an urgent task to realize geophysical explorations with high precision and high efficiency in complex environments. It has been found that the traditional transient electromagnetic method (TEM) had a series of problems related to theory, method, and instrument, as well as data interpretation. Based on the reviews of present TEM achievements, three new improved measurements are introduced. The central‐loop system was improved by a large fixed‐loop system; the long‐offset system was changed to the short‐offset one; the resistivity profile was transformed into a virtual wave‐field profile. Finally, this paper points out that the future research direction of the TEM method is in terms of equipment, data processing, and big data information. [ABSTRACT FROM AUTHOR]

Previously, the multi‐channel transient electromagnetic (MTEM) system has been successfully developed and applied to hydrocarbon reservoirs exploration on land and offshore environments in France. In order to explore the mineral resources buried at the depths up to 2,000 m in China, we developed a new MTEM system. In this paper, we present the components of the system, methods, principles, the parameters of the system, and the data interpretation method. To validate the effectiveness of the methodology and the developed system, we carried out an MTEM survey to locate the controlling faults of a gold deposit in the east of China. The survey contains 30 receivers distributed over 12‐km survey. By comparing the MTEM interpretation results with the known geological background, we find that MTEM methods can provide a good estimation of the ore‐controlling faults and this method could be a potential tool for the future deep mineral exploration. [ABSTRACT FROM AUTHOR]

The southern West Junggar terrane in the south‐western Central Asian Orogenic Belt (CAOB) is mainly composed of accretionary complexes and characterized by widespread outcrops of ophiolitic mélanges in the Barleik, Mayile, and Tangbale (BMT) areas, representing the site of consumption of the Junggar–Balkhash Ocean. However, due to a lack of comprehensive synthesis of the ophiolitic mélanges, the early evolution of the Junggar–Balkhash Ocean remains poorly understood. This paper first focuses on the little‐known Barleik ophiolitic blocks and associated pillow basalts and then integrates the Barleik, Mayile, and Tangbale ophiolitic mélanges into one model. Mineral and whole‐rock chemistry suggests that the Barleik ophiolitic blocks, including serpentinized dunite, clinopyroxenite, and gabbro, show supra‐subduction zone (SSZ) affinities, as indicated by high Cr# values (76–78) in spinels and strong depletion in Nb, Ta, Zr, and Hf, whereas the Barleik pillow basalts are alkaline and have high TiO2 contents (2.82–3.42 wt.%) and Nb–Ta enrichment, similar to ocean‐island basalt (OIB) lavas. Combined with published chronological and chemical data from ophiolites, metamorphic rocks, and arc plutons, we propose that the BMT Ediacaran to middle Cambrian ophiolitic gabbros were formed in a SSZ environment, implying a single Mariana‐type arc system within the Junggar–Balkhash Ocean, which was coeval with an Andean‐type arc system in the Kyrgyz North Tianshan, supporting an archipelagic model for the south‐western CAOB. By contrast, the BMT OIB‐type basalts are early Silurian in age, much younger than the SSZ‐type ophiolites, and can be interpreted as relicts of seamounts. Thus, a model involving the Ediacaran to Ordovician intra‐oceanic subduction and late Silurian to Early Devonian seamount accretion is helpful for clarifying the different components of the accretionary complexes in the southern West Junggar terrane. [ABSTRACT FROM AUTHOR]

The Jiapigou gold ore belt is located in the northeastern corner of the wedge‐shaped North China Craton and is hosted by Neoarchean basement gneiss and amphibolite, along with late Palaeozoic and Mesozoic granitoids. In this paper, whole‐rock major and trace element geochemistry together with zircon U–Pb ages and Lu–Hf isotope compositions are reported for Late Permian to Triassic igneous rocks from the gold belt. The dominant population of zircons in all these rocks shows oscillatory growth zoning in CL images, and relatively high Th/U ratios (0.10–5.23) that are indicative of a magmatic origin. Zircon U–Pb data indicate that the igneous rocks formed during two major phases: ca. 252 Ma and ca. 230–213 Ma. Geochemically, the Late Permian (ca. 252 Ma) diorites are high‐K calc‐alkaline in composition and low total Fe2O3, MgO, and CaO contents, and represented by enrichment in LILEs relative to HFSEs and HREEs, all of which are indicative of a postcollision high‐K calc‐alkaline granite affinity. In contrast, the Late Triassic (ca. 230–213 Ma) igneous rocks are mainly quartz syenite porphyries, felsites, and granodiorites, and are variable medium‐ to high‐K calc‐alkaline series and exhibit a negative Eu anomaly with A‐type affinities, indicating an extensional environment. In addition, in situ Hf isotopic analyses of zircons from four dated samples reveal that they have εHf(t) values of −3.0 to +2.2, with two‐stage model (TDM2) ages range from 964 to 1,210 Ma, indicating that they probably originated from the partial melting of a dominantly Mesoproterozoic to Neoproterozoic crustal source. On the basis of the geochemical data and regional geological investigations, we further propose that the Jiapigou gold ore belt in the Late Permian was formed in a postcollisional tectonic setting, whereas an extensional tectonic setting in the Late Triassic that caused lithospheric thinning during a postorogenic event. [ABSTRACT FROM AUTHOR]

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

Rapid expansion of shale gas development in China raises environmental and human health concerns. Several studies present related information on these concerns in the United States and Canada, yet they are few in China at present. This paper presents a series of original and published mineralogical and trace elements data from two gas shales (Niutitang shale and Longmaxi shale) considered as producing gas shale in China. Mineralogical and geochemical data surveyed can be applied to evaluate the potential environment pollutions during shale weathering and hydraulic fracturing. After compilations of the mineralogical and trace elements data, we can conclude that (a) there is generally more pyrite compared with carbonate for Niutitang shales, indicating that Niutitang shales are more prone to generate the hydrogen ions than Longmaxi shales; (b) many of the environmental hazardous trace elements considered here show an association with organic matter and/or pyrite, indicating that these trace elements are prone to mobilize and release during shale weathering and hydraulic fracturing; (c) some environmental hazardous elements like As, Ni, and Ba that have extremely high concentrations in some regions as compared with the screening limits for soil and drinking water should attract more attention; and (d) clay‐rich shale with abundant organic matter may be the most favourable shale gas reservoir for the Niutitang shale, especially for those shales in Lower Yangtze region. Moreover, more mineralogical and geochemical data will be required for a comprehensive environmental impacts assessment. [ABSTRACT FROM AUTHOR]

Outcrops of early Palaeozoic mafic rocks are limited in the South China Block (SCB), which become a barrier to unlock the related tectonic evolutionary history. We present a new report of early Palaeozoic Pengxi hornblendite at Xiajiang County, Jiangxi Province, in this paper. The Pengxi hornblendite has a concordant zircon U–Pb age of 433 ± 2 Ma (40 grains) which could represent its formation time. It is characterized by high MgO content (16.8–19.6 wt.%) and Mg# (78–80), compatible elements concentration (Ni = 280–506 ppm, Cr = 1,580–1,780 ppm), and evident depletions of Nb, Ta, and Ti which are similar to the arc‐related magmatism. Combining with the enriched Nd (εNd(t) = −5.3 to −7.8) isotopic feature, we suggest that the hornblendite was derived from partial melting of metasomatized subcontinental lithospheric mantle (SCLM). The lack of other field geological evidences in the study and adjacent areas, such as volcanic rocks, pyroclastic sedimentary rocks, and turbidites, did not support the contemporaneous subduction model. The study area is located near the boundary of the Yangtze and Cathaysia blocks which was a Neoproterozoic subduction belt characterized by ophiolites, volcanic rocks, and turbidites. Mafic rocks formed at different periods (e.g., 800, 500, and 430 Ma) in the SCB have similar enriched Nd isotopic compositions and La/Nb ratios which suggest that the Silurian hornblendite with arc‐like geochemical features may not be the result of contemporaneous subduction but likely inherited from the Neoproterozoic subduction. During Silurian post‐orogenic collapse event, the partial melting of enriched SCLM generated the Pengxi hornblendite. This work can provide new data to the further discussion of the controversies in the tectonic background of the SCB. [ABSTRACT FROM AUTHOR]

The Lesser Xing'an–Zhangguangcai Range is located in the eastern part of the Central Asian Orogenic Belt (CAOB). Early Mesozoic igneous rocks in this area can place constraints on the crustal growth mechanism in the Northeastern China. This paper reports a suite of Late Triassic high‐Mg diorites and mafic dikes from the southern Lesser Xing'an–Zhangguangcai Range. The mafic dikes have younger zircon U–Pb ages of 195 ± 2 Ma. They display intermediate SiO2 (50.58% to 58.20%) and high Na2O/K2O ratios of 1.90 to 3.20, low A/CNK ratios of 0.75 to 0.84, low (87Sr/86Sr)i ratios of 0.7045 to 0.7046, and high εNd(t) values of +3.1 to +3.5. Most zircons in the mafic dikes exhibit positive εHf(t) values from +8.6 to +16.0, with single‐stage Hf model ages ranging from 0.2 to 0.5 Ga in combination with their enrichment in LREE and LILEs and depletion in HFSEs. They are considered to be formed by melting of metasomatized subarc lithosphere mantle. The diorite and quartz diorite have older zircon U–Pb ages of 200 ± 3 and 202 ± 2 Ma, respectively. They have SiO2 = 54.45% to 61.18%, Al2O3 = 17.16% to 19.10%, TiO2 = 0.74% to 1.13%, and Mg# = 46.6 to 49.5, and they also display moderately depleted Sr–Nd (εNd(t) = +2.3 to +4.3) and zircon Lu–Hf (εHf(t) = +8.6 to +16.0) isotopic compositions. These features suggest that they were formed by melting of juvenile arc crust in active continental margin. Considering the occurrence of the contemporaneous and latter igneous rocks in the Zhangguangcai Range, we argue that the diorite, quartz diorite, and mafic dikes from the Lengshan area were also related to the westward subduction of Palaeo‐Pacific Plate (Izanagi Plate) beneath the Eurasian Plate. The strike‐like fault along the eastern margin of the Songneng–Zhuangguangcai Block may play an important role in the genesis of diorite melt. [ABSTRACT FROM AUTHOR]

Carboniferous volcanic rocks are widely distributed in the Junggar Basin and may provide a unique insight into the tectonic history of this basin. In this paper, we focus on the tectonic evolution of the northern Junggar Basin (NJB) using geochronological and geochemical data to establish the diachronous closure model for the Keramaili oceanic basin. The Lower Carboniferous strata in the eastern part (well WC‐1) and the Upper Carboniferous strata in the western part (well Y‐2) of the NJB are composed of a mix of compositional and rock‐type forms. These volcanic rocks are mostly high‐K assemblages characterized by high K (1.73–6.48%), high alkali (Na2O + K2O = 5.04–7.45%), and low TiO2 (0.57–1.06%). They also exhibit various REE concentrations (68.44–168.19 ppm), an enrichment of LREE (LaN/YbN = 4.54–8.09), and small negative Eu anomalies (δEu = 0.74–0.90). The depletion of HFSE and relevant tectonic setting discrimination diagrams demonstrate that these two volcanic associations were formed in a subduction‐related environment. The data also indicate that the high‐K volcanic rocks are derived from a mix of melted subducted sediments and mantle metasomatized by silica‐rich fluids. Although these two sets of volcanic rocks formed in Early and Late Carboniferous, the similar petrographic and geochemical natures suggest similar magma source and tectonic setting. Along with different regional tectonic settings in the NJB during the Carboniferous, we propose an asynchronous subduction of Keramaili oceanic basin, resulting in the inconsistent temporal and spatial distribution of Upper Carboniferous volcanic rocks in the NJB. [ABSTRACT FROM AUTHOR]