The scraper conveyor, as a large-scale transportation equipment in coal mine longwall mining faces, plays a crucial role in the coal transportation process. The middle trough, being the component of the scraper conveyor that comes into contact with coal the most, experiences impacts and wear that directly affect its service life. Due to the fact that scraper conveyors often operate underground in complex and harsh environments, it is challenging to conduct effective experimental research. Experimental studies under such complex working conditions are difficult to carry out, making it hard to investigate the wear generated between the middle trough of the scraper conveyor and the coal material. To address this, a coupled model of the scraper conveyor was constructed using multibody dynamics and the discrete element method. The wear on the middle trough of the scraper conveyor caused by different types of coal bulk materials was analyzed, focusing on the transportation behavior of coal bulk materials with varying particle sizes within the middle trough. The results indicate that coal particles of different sizes exhibit a stratification phenomenon during transportation, with distinct movement patterns observed for each particle size. Based on Archard's wear theory and the discrete element method, a simulation analysis of the wear on the middle trough was conducted using the controlled variable method to study the impact of coal particles with different particle sizes on the wear depth of the middle trough. The results showed that compared to larger coal particles, smaller coal particles cause more severe wear on the middle trough. This is primarily because smaller particles are more likely to cause three-body wear during the scraper transportation process, and the wear caused by three-body interactions is significantly greater than that caused by two-body wear. Based on the above conclusions, in practical applications, it is essential to enhance the wear resistance of the regions in the middle trough that are most prone to severe wear. Simulation experiments should be conducted to verify the wear conditions in different areas of the middle trough. This approach provides theoretical guidance for improving the transportation efficiency of the scraper conveyor and extending the service life of the middle trough. Additionally, it offers new research perspectives for optimizing the model of the scraper conveyor.

Hot dry rock (HDR), a widely distributed geothermal resource, holds significant development potential. The geometric characteristics and distribution of the fracture system within the reservoir are crucial, as they directly influence the flow paths and storage capacity of underground fluids. This study establishes a predictive framework for granite-type hot dry rock (HDR) reservoirs in China's Gonghe Basin by integrating field data, stochastic discrete fracture network (DFN) modeling, and geomechanical upscaling. Natural fractures, characterized via imaging logging, cores, and outcrops, exhibit three dominant orientations (NW, NNW, NE) and a power law size distribution. Monte Carlo simulations translated 1D fracture density (P10) into volumetric constraints (P32), enabling 3D DFN construction. Oda-based upscaling revealed permeability anisotropy, with maximum values of 0.268 mD (x-direction), 0.277 mD (y-direction), and 0.135 mD (z-direction), governed by low-dip NE/NW fractures, alongside reduced Young's modulus, Poisson's ratio and localized stress perturbations in fracture-rich zones. Simulated in-situ stresses aligned with field measurements, validating the model. The workflow bridges multi-scale data gaps, offering critical insights for optimizing hydraulic fracturing in low-permeability HDR systems.

The Mahu Sag, where the Mahu 1 well block is located, is one of the most important hydrocarbon-rich depressions in the Junggar Basin, NW China. The Permian Upper Wuerhe Formation (UWF) constitutes the primary layer of the unconventional tight oil reservoir in the Mahu Oilfield. To explore the provenance and sedimentary environment during the deposition of the UWF in the study area, we determined the clay mineralogy and whole-rock geochemical composition of argillaceous rocks. The results show that the primary minerals in argillaceous rock are feldspar, clay minerals, quartz, and a minor amount of hematite. The clay minerals identified included illite, smectite, kaolinite, chlorite, and illite/smectite mixed layers. The tectonic setting of the provenance area for the UWF is a continental island arc, associated with a cutting magmatic arc. The main provenance area is related to the Baogutu tectonic belt (the Zhayier Mountain and the Hala’alate Mountain). The bedrock primarily consists of acidic igneous rocks, with minor occurrences of intermediate–basic igneous and sedimentary rock. The chemical index of alteration (CIA) shows that the parent rocks of the argillaceous rocks have experienced moderate–strong chemical weathering. Combining the Sr/Cu and ΣLREE/ΣHREE ratios, δEu values, and clay mineral characteristics, we determined that the paleoclimate during the deposition of the UWF was generally warm and humid, with occasional short-term dry and cold periods. The UWF gradually changes, according to the relative humidity and enhanced chemical weathering from the bottom to the top. An analysis of trace elements, paleosalinity, and paleowater depth indicate that the studied argillaceous rocks were deposited in a shallow-water oxidation environment of continental fresh water with weak hydrodynamic conditions.

Myanmar, located at the southern edge of the Eastern Himalayan Syntaxis, plays a crucial geological role in understanding the interaction between the Indian and Eurasian plates. While previous studies have employed various methods to investigate the subducting slab beneath Myanmar, the fine-scale structure of the slab, particularly beneath the Indo-Burma Ranges, remains unresolved. In this study, we utilize seismic data from a dense seismic array across the Indo-Burma Ranges in central Myanmar to investigate the structural characteristics of the subducting slab. Using receiver function analysis, we identify a series of seismic discontinuities associated with the subducting Indian slab. By integrating geodetic and seismicity data, our imaging reveals that the Indian slab beneath central Myanmar is a continental slab and highlights the presence of a shear zone or detachment layer above it. These findings provide new insights into the subduction process and contribute to a deeper understanding of the tectonic evolution of the Indo-Burma region.

The Fushan Depression is a hydrocarbon-rich depression in the Beibuwan Basin, South China Sea. In this study, 14 source rocks and 19 crude oils from the Chaoyang Step-Fault Zone and Southern Slope Zone were geochemically analyzed to determine their origins. The hydrocarbon generation, migration, and accumulation processes were also determined using two-dimensional basin modeling. Crude oils from the low-step area show a close relationship with the source rocks of the first and second members of the Eocene Liushagang Formation (Els1 and Els2). The oils from the middle-step area and the Southern Slope Zone are derived from the local source rocks in those areas, in the third member of the Eocene Liushagang Formation (Els3). Hydrocarbons generated from the Els3 source rocks of the Southern Slope Zone migrated along sand bodies to the Els3 reservoir. The fault system of the Chaoyang Step-Fault Zone controls hydrocarbon migration and accumulation in the low-step and middle-step areas. The resource potential of the middle-step area is limited by its shallow burial depth. The low-step area is a more favorable exploration area due to its proximity to the source kitchen.

Basement inherited structures represent a significant factor affecting thrust propagation dynamics during the growth of fold-and-thrust belts. In this study inspirited from seismic data analysis of Gaoquan anticline in the Northern Tianshan foreland basin, we devised an experimental approach to investigate the structural and kinematical evolution of deformation from preexisting basement restraining bend to subsequent contractional deformation. Tested parameters included reactivation of the basement restraining bend and erosion. Results indicated that when preexisting basement restraining bend was reactivated and folded an overlying decollement, subsequent thrust nucleated preferentially at the top of the folded decollement. Erosion helped localize deformation, thereby reducing the width of the deformation zone and promoting "out-of-sequence" thrusting during compression. Finally, as we employed silicone polymer to simulate overpressured mudstone layer in the major decollement, our experiments also provide insights into a better understanding of the relationship between shallow salt-detached thrusting and deep inherited basement structures, such as in the Jura Mountains structures.

Understanding the role of microbiota on stone surfaces is essential for developing effective grottoes conservation strategies. However, ecological feature of microbial communities on stone surfaces remains underexplored. In this study, we explored diversity, ecological feature, and functional profiles of microbial communities on the red sandstone surface of the Leshan Giant Buddha from microbial ecology perspective. The results show that Proteobacteria, Actinobacteria, and Cyanobacteria are the dominant prokaryotic phyla, and Ascomycota is the most dominant eukaryotic phylum. Interestingly, despite taxonomic divergence, the functional profiles of different types of the microbial communities remain convergent across all samples. As indicated by the ecological modelling, the interplay of dispersal limitation and hetero selection might have contributed to such species divergence, while selective pressure from the harsh environment on the stone surface promoted functional convergence. The assembly of visually distinct microbial communities is linked to a narrower ecological niche, higher proportion of habitat specialists, elevated complexity, and increased resilience of the prokaryotic network to disturbances. Microbial-mediated ammonium assimilation and nitrogen mineralization might be the two prominent processes that contribute to stone biodeterioration. This study deepens our understanding of microbial community assembly mechanism on stone cultural heritage surfaces and functional potentials, which provides microbial ecological insights for the conservation of these cultural treasures. ### Competing Interest Statement The authors have declared no competing interest.

Mid-deep geothermal reinjection technology is crucial for the sustainable development of geothermal resources, which has garnered significant attention and rapid growth in recent years. Currently, various geothermal reinjection technologies lag behind, lacking effective integration to address issues like low reinjection rates and thermal breakthrough. This paper reviews the basic principles and development history of mid-deep geothermal reinjection technology, focusing on various technical methods used in the process and analyzing their applicability, advantages, and disadvantages under different geological conditions. It highlights the unique challenges posed by deep geothermal resources, including high temperature, high pressure, high stress, chemical corrosion, and complex geological structures. Additionally, it addresses challenges in equipment selection and durability, system stability and operation safety, environmental impact, and sustainable development. Finally, the paper explores future directions for mid-deep geothermal reinjection technology, highlighting key areas for further research and potential pathways for technological innovation. This comprehensive analysis aims to accelerate the advancement of geothermal reinjection technology, offering essential guidance for the efficient reinjection and sustainable development of geothermal resources.

The Western Kunlun Orogenic Belt (WKOB), along the northwestern margin of the Qinghai-Xizang Plateau, was formed by the collision of Gondwana-derived terranes to the south and the Tarim Block to the north and was closely associated with closure of the Proto-Tethys Ocean during the late Neoproterozoic to early Paleozoic. We present a combined zircon U-Pb geochronology, whole-rock composition, and Sr-Nd-Hf isotopic study of syncollisional granitoid plutons and mafic microgranular enclaves (MMEs) in the region. Zircon U-Pb dating yields ages of 443.8 +/- 4.4, 451.9 +/- 4.2, 462.9 +/- 3.5, and 456 +/- 4.2 Ma for the Tongayoupuagezi, Shanjie, and Pishigai plutons and MMEs from the Pishigai pluton, respectively. The granitoids are metaluminous to weakly peraluminous (A/CNK = 1.00-1.17) and belong to the high-K calc-alkaline series. They have (87Sr/86Sr)i ratios of 0.7058-0.7154, epsilon Nd(t) values of -8.78 to -0.93, and epsilon Hf(t) values of -19.72 to +6.87. The MMEs have variable SiO2 contents (45.7-60.2 wt%) and are more mafic than the host granitoids, but have similar Sr-Nd-Hf isotopic compositions to the host granitoids [(87Sr/86Sr)i = 0.7102-0.7110; epsilon Nd(t) = -6.57 to -3.56; epsilon Hf(t) = -7.17 to -1.81]. The MMEs are fragments of cumulates formed during the early stages of magma evolution. The granitoids were produced by the partial melting of a melange source. The new data support the view that the Middle-Late Ordovician syn-collisional granitoids with MMEs distributed along the WKOB represent a magmatic response to terrane collision. This suggests that juvenile crustal growth in older orogenic systems, which occurs by arc addition, also involves some vertical addition during the final stage of orogenic collision. Our study suggests that melange diaper melting is a key mechanism of crustal growth during the syn-collision stage in continental collision zones, associated with slab breakoff.

In the rejuvenated mountain front, preexisting basement structures are often reactivated and interact with the subsequent thin-skinned deformation. How the deep structures affect the shallower ones is key to establishing the processes and mechanisms for the foreland fold-and-thrust system. We presented an exceptional case study on the structural inheritance between the deep Mesozoic strike-slip faults and the shallow Cenozoic contractional folds from the Northern Tianshan foreland basin, Northwest China, using high-resolution 2-D and 3-D seismic data. Based on the interpretation of seismic data and progressive restoration, our study illustrated the NW-trending Ai-Ka strike-slip faults controlled a dextral shear zone, which initiated the Gaoquan restraining bend in the basement during Jurassic. Later, these strike-slip structures, close to the mountain front, were reactivated during the N-S Mio-Pliocene contraction, and folded the upper decollements that characterized the localization of thin-skinned deformation. In contrast, in the further foreland, nonreactive strike-slip faults controlled basal decollement pinch-out, which localizes the thin-skinned deformation, resulting in en echelon folds that trace the strike of the deep strike-slip faults. The onset time of each anticline shows that the thin-skinned deformation first extended laterally and then propagated further north, resulting in ca. 7 km shortening along the whole foreland. Moreover, the shortening rate decreased eastward from 0.90 to 1.46 mm/yr along the Gaoquan-Kayindike structural line to 0.24-0.37 mm/yr along the Dunan structural line as the Sikeshu depression, constrained by the NW-trending Ai-Ka strike-slip fault, narrowed eastward. This feature implies that the width of the depression may control the amount of displacement propagation. The geometry and kinematics of Mesozoic transpressional and transtensional structures were documented using 3-D seismic data The Mesozoic strike-slip faults affected the localization of Cenozoic thin-skinned folding by creating pinch-out or folds in the decollement Cenozoic forelandward folding consumed 7 km S-N shortening. Shortening rate decreased from 0.90-1.46 to 0.24-0.37 mm/yr eastward

In central Asia, the Tianshan mountains have undergone a series of subduction-collision-accretion processes during Paleozoic times that resulted in forming basement structures later reactivated during the Cenozoic rejuvenation of the range. In the northern Tianshan-South Junggar foreland basin, en échelon W-E / WNW-ESE folds constitute the large-scale fold-and-thrust belt (FTB). Using recent industrial 2-D and 3-D seismic surveys carried out in the western area of the FTB, we have analyzed outcropping structures (Dushanzi and Xihu anticlines) and buried structures (Gaoquan, Kadong, Kayindike, and Dunan anticlines). Observing that the strike of these structures changes from W-E in the east to NW-SE in the west, we investigated the parameters that controlled this lateral variation along the FTB. We particularly analyzed the structural and kinematic relationships between deep Mesozoic and shallow Neogene-Quaternary structures. We support our investigation by using seismic interpretation and balanced restoration. Our results provide new insights into the structural and kinematical history of the Mesozoic-Cenozoic tectonic evolution of the northern Tianshan foreland basin, and into the record of deformation propagation. We first demonstrated that the tectonic and sedimentary evolution during the Triassic and Jurassic is characterized by NW-SE and NNW-SSE strike-slip faults that controlled the development of pull-apart and restraining bend systems. These features were partially reactivated during the Neogene-Quaternary contractional deformation, depending on their position relative to the mountain front. Second, we quantified that about 7 km of total S-N shortening has been accommodated across the western area of the FTB. We also quantified the displacement rate accommodated on every single structure. It is ~0.13-0.2 mm/yr in the Gaoquan anticline since Quaternary, ~0.19-0.30 mm/yr in the Dunan anticline since Quaternary, ~0.36 mm/yr in Dushanzi anticline since Pliocene and ~0.30-1.2 mm/yr in the Xihu, Kadong and Kayindike anticlines during Quaternary times. Additionally, the rate of thrusting above the reactivated strike-slip faults in the Gaoquan anticline is 3 to 6 times lower than that of thrusting above the inactive strike-slip faults of the Kadong and Kayindike anticlines. This suggests that the reactivation of the basement strike-slip fault zone partitioned the contractional strain during Quaternary times. Finally, we integrate our results in a 3-D model of the western area of the FTB that illustrates the spatial pattern of structures at depth. Notably, it emphasizes how deep Mesozoic structures exerted a primary control on the growth of Cenozoic thrust-related folds by localizing the nucleation of thrust ramps during compression. This pattern of deep vs. shallow deformation interaction might be applied in some other areas of the Tianshan foreland basin.

The Junggar Basin in Northwest China is covered by thick sediments, causing challenges in recognizing buried structures. Seismic reflection and drilling data from petroleum exploration provide essential data for the study of subsurface structures. In this study, we focus on the Mesozoic structural characteristics and tectonic evolution along the margins of the Junggar Basin by using 2D and 3D seismic reflection, drilling data, and surface geology. Our results demonstrate that a unified dextral strike-slip fault system developed along the marginal area around the Junggar Basin. The structural style is characterized by both transpressional structures, such as positive flower structures, en echelon folds, restraining bends, and fan-shaped and horsetail fractures at the fault tip, and transtensional structures, including releasing bends, pull-apart basins (fault basins), and positive inverted structures. We further interpret that except for the southern margin of the Junggar Basin, the current structural pattern of the basin margin was mainly formed in the pre-Cretaceous, which was covered by Cretaceous and Cenozoic strata. Based on the timing and style of deformation, we propose that the vertical-axis counterclockwise rotation of the Junggar Basin during the Mesozoic caused right-lateral strike-slip faulting along the basin margin. Cenozoic reactivation of these structures has been localized in the southern margin of the Junggar Basin under the far-field influence of the India-Asia collision.

The Qianyingzi Coal Mine is located in the west of the Suxian Mining District of the Huaibei Coalfield, eastern China. The study on structural development patterns and genetic mechanisms in this mine lays an important foundation for safe and efficiently underground mining, and is also the key to understanding the regional tectonic evolution. In this study, based on the analysis of three-dimensional seismic, drilling and underground measured data and regional tectonic correlation, the structures, evolution history and dynamic background of the Qianyingzi Coal Mine are discussed. The Carboniferous-Permian coal measure strata in the mine are generally a gentle syncline with a NNE-trending axis, and cut by a series of faults. The faults developed in this mine are mainly medium- and small-sized with a throw of less than 20 m, and the number of reverse faults is significantly greater than that of normal faults. The strikes of reverse and normal faults are both mainly NE, followed by NNE and nearly N‒S. According to the characteristics of structural geometry, tectonic association, fault property and cross-cutting relation, the structural deformation of coal measure strata in the Qianyingzi Coal Mine can be divided into five stages, and the corresponding tectonic stress fields are NWW‒SEE compressive stress, nearly E‒W compressive stress, NW‒SE compressive stress, nearly E‒W and NW‒SE extensional stresses, respectively. It developed the Fengjia Syncline with a NNE-trending axis in the first stage and nearly N‒S-striking reverse faults in the second stage, which were the results of foreland deformation and subsequent continent-continent collision during the convergence of the North China Craton and South China Plate in the Indosinian period. The NNE-striking reverse sinistral faults and NE-striking reverse faults developed in the third stage is related to the rapid oblique subduction of the Izanagi Plate toward the East Asian continental margin at the beginning of the Early Cretaceous in the western Pacific region. Later, the fourth and fifth stages of the nearly N‒S- and NE-SW-striking normal faults were developed under the backarc extensional background in eastern China during the Early Cretaceous. These new results can be used to guide the rational arrangement for underground mining and also provide a new understanding for regional tectonic evolution of the Huaibei Coalfield.

Marginal seas are major sinks of fluvial sediments. Identifying the sources and quantifying the contributions of different sources are essential to studying the transport and distribution of terrestrial sediments on the shelves of marginal seas. The South Yellow Sea (SYS) to the east of the Asian continent receives sediment discharged by the Huanghe (Yellow) and Changjiang (Yangtze) rivers, and it is a favorable location for studying the provenance of marginal sea deposits. In this study, we tested the geochemistry of amphibole in different grain-size fractions (very fine sand and coarse silt) of the SYS sediments, and compared this geochemistry with those of fractions in the Huanghe River (HH) and the Changjiang River (CJ) to quantify the terrestrial provenance of the sea. The results show that for the very fine sand fraction, Zr, Be, Ga, Ge, Nb, Cd, and Hf in amphibole can be used as indicators to discriminate between the HH and CJ sediments. For the coarse silt fraction, the trace elements of Ba, Zr, Li, Rb, and Hf in amphibole can be used to distinguish the sediment of the two rivers. The mean contribution of the HH sediment to the very fine sand and coarse silt fractions of SYS is 45.0% ± 6.7% and 57.6% ± 5.9%, respectively, compared with 54.8% ± 6.7% and 42.4% ± 5.9% for the CJ, respectively. Provenance analysis of amphibole reveals spatial variation in the supply of terrigenous sediment to different parts of the SYS: the nearshore area of the Shandong Peninsula and the sea areas adjacent to the abandoned Huanghe River (FHH) estuary are supplied mainly by the HH, whereas the South and eastern parts of the SYS are supplied predominantly by the CJ. In the SYS sediment of very fine sand, a line extending from 34°N, 121°E to 35°N, 123°E demarcates the boundary between areas supplied by the HH (north) and the CJ (south), while coarse silt has a longer transport distance and higher mixing degree compared with very fine sand. This study demonstrates that quantitative analysis of the trace-element geochemistry of detrital amphibole can discriminate terrigenous sediment provenance in the mixed area of the marginal sea.

With the exploration maturation of structural traps, stratigraphic traps formed by gravity flow deposition have gradually become an important target for increasing hydrocarbon reserves and production. In order to effectively predict the reservoirs of sublacustrine fans deposited in the eastern slope of Liaoxi uplift (Bohai Bay Basin, East China), it is necessary to figure out their development characteristics and controlling factors. In this paper, geomorphology and architecture of sublacustrine fans in Dongying Formation and their controlling factors (including shape and formation) have been analyzed in detail, based on seismic data, core data and logging data. The main conclusions achieved in this study are: (1) during the sequence of the third member of Dongying Formation (SQd 3 ), two types of sublacustrine fan, including channelized fan and non-channelized fan, developed on the eastern slope of Liaoxi uplift, which inherited the characteristics of sediments structural maturity in braided river delta front (good sandstone sorting and high structural maturity); (2) it can be divided into three forms of sublacustrine fans, including tongue shape, leaf shape and channel shape, in which steep slope was favorable for forming tongue shape sublacustrine fans with large ratio of length and width, while gentle slope tended to deposit leaf shape fans, and high mud content tended to form stable channels; (3) in the basin with uplift, the beneficial combination among provenance, relative lake level change and paleogeomorphology, determines the development and distribution of sublacustrine fan, and the sublacustrine fan deposits are mainly concentrated in the TST.

The tectonics of continental rift basins and the accompanying deposition processes are areas of increasing research interest. The Ondor Sum uplift is located in the southern Erlian Basin, NE China. It is a promising site for petroleum exploration. In this study, we used 2D and 3D seismic, well-log and core data to conduct a tectono-sedimentary analysis of the sags of the Ondor Sum uplift. Three types of depositional systems were identified, including fan-delta, braided-delta and lake depositional systems. Of these, the fan-delta and lake deposits are highly developed, while the distribution of braided-delta deposits is limited. The rift sags in the area consist of a SE-faulting and NW-overlapping type, a NW-faulting and SE-overlapping single-faulted dustpan-like rift sag and a double-faulted rift sag. The tectonic evolution models of the area were of two types: an inheritably-developed type, applicable to the single-faulted dustpan-like rift sag and double-faulted rift sag, and a structurally migrated type. The early-to medium-term-activated as well as the long-term-activated faults controlled both the sediment filling of the Wulanhua and Chazhong sags and the distribution of their sand bodies. Both differential and balanced uplifting during the Late Yanshanian period determined the stratigraphic development and configuration of the sags. Given the similarities the sags of the Ondor Sum uplift shares with the petroliferous sags of the inner Erlian Basin, combining with the petroleum discovery in the Wulanhua and the Chazhong sags and relatively shallow burial depth of the target layers, the sags in this area are likely to contain hydrocarbons and should thus be explored for their resource potential.

Due to remarkable reduction of sediment supply, the vulnerability of Yellow River deltaic system increased and ecological impacts occurred to some extent. To have a comprehensive and quantitative understanding of the morphological evolution of deltas, surficial sediments of tidal flat along the abandoned southern Yellow River sub-delta and two adjacent coastal units were systematically collected and evaluated by grain-size analysis in the study. The results reveal that surficial sediments of the abandoned southern Yellow River sub-delta have been coarsening significantly since the 1980s, as characterized by a decrease in both the mud content and the clay/mud ratio. In particular, the transition from cohesive to non-cohesive sediment was completed between 2007 and 2013. With a sharp decrease in sediment flux from the Yellow River estuary, the flood currents from the submarine coastal slope carry few fine particles into the tidal zone, whereas the ebb currents with reverse direction remove some fine particles from the tidal flat. This is a major cause of sediment coarsening in the tidal flat. As sediment coarsening, the coastline of the abandoned southern Yellow River sub-delta has remained stable. The significant change in the grain size of the tidal flat surficial sediments may have a profound impact on the future coastal geomorphic evolution.