We reestablished the Serratognathus bilobatus Biozone in the Taebaek Group of Korea, where Serratognathus bilobatus was first reported by Lee (1970), based on new data from the uppermost Dumugol Formation to the Lower Makgol Formation at the Seokgaejae Section, Taebaeksan Basin. The conodont fauna includes several first-reported species in Korea of Acodus shitaianus, Bergstroemognathus extensus, B. pectiniformis, Paraserratognathus incostatus, Nasusgnathus dolonus, Rhipidognathus yichangensis. The co-occurrence of the Serratognathus bilobatus and comparison of associated species with other continents show similar results with the biogeographic link of eastern Gondwana during the Early Ordovician proposed as the "Australasian Superprovince". The highest similarity with North China reaffirms that Taebaek Group is part of North China paleoplate. The relatively low similarity with western Australia, Tarim, Sibumasu and Kazakhstan, and high similarity with South China indicate that the Taebaeksan Basin was located in closer proximity to South China than other continents during Floian. Serratognathus bilobatus, which occurred from the nodular limestone and lime mudstone in this study, has been recovered in wide range of depositional facies including limestone dominated and siliciclastic-carbonate mixed facies in other continents of eastern Gondwana. This study suggests that the widespread distribution of Serratognathus bilobatus might be related to the depositional environment.

Microorganisms actively participate in biogeochemical cycling processes and play a crucial role in maintaining the dynamic balance of hot spring ecosystems. However, the distribution of microbial functional genes and their influencing factors in hot springs remain largely unclear. Therefore, this study investigated the microbial functional genes and their potential for controlling biogeochemical cycles (C, N, S, and P) in the hot Springs of Tengchong, China, using the Geochip method, a functional gene microarray technology. The examined hot springs have very different microbial functional genes. A total of 22 736 gene probe signals were identified, belonging to 567 functional genes and associated with 15 ecological functions, mainly involving stress response, carbon cycle, nitrogen cycle, sulfur cycle, phosphorus cycle and energy processes. The amyA, narG, dsrA and ppx genes were most abundant in carbon, nitrogen, sulfur and phosphorus cycles, respectively, and were significantly correlated with pH, temperature and SO₄^2-. The diversity and abundance of detected gene probes were negatively correlated with temperature. The α-diversity (i.e., Shannon index) was high at low temperature and low pH. Molecular functional interactions revealed by the gene connectivity levels were negatively correlated with temperature, pH and SO₄^2-. These results suggested that the abundance, diversity and interactions of microbial functional genes were significantly influenced by geochemical parametersֿ. In addition, some genera possessed functional genes related to carbon, nitrogen, sulfur, and phosphorus cycles and can synergistically control the biogeochemical cycles of carbon, nitrogen, sulfur and phosphorus. These findings provide new insights into the functional potentials of microorganisms to participate in biogeochemical cycles and their responses to environmental factors in hot springs.

Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance. Bacterial interaction is one of the main factors in shaping soil bacterial communities. However, how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau (QTP) remains largely unknown. Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River (TTH) and May 2022 for Aerjin (ARJ), and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene. Our study revealed distinct bacterial communities, with significant differences in the relative abundances of Proteobacteria (P < 0.05), Acidobacteriota (P < 0.001), Bacteroidota (P < 0.05), and Planctomycetota (P < 0.001) between the active layer and the permafrost layer. More importantly, we found that interspecies interactions, including both positive and negative associations, were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process. Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes, with interspecies interactions accounting for more than 58% and 63% of all assembly mechanisms, respectively. This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP, highlighting the importance of considering interspecies interactions in future modeling efforts. Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.

The Monte Desert is characterized by a great diversity of landforms created with fluvial, alluvial which the vegetation patterns are related to. The present work has the following objectives: (1) determine whether topographical attributes, surface characteristics, soil properties and vegetation patterns vary between alluvial landforms, and (2) define whether morphometric, soil and surface properties influence vegetation patterns along alluvial landscape. Morphometric data were obtained by processing a 5 m digital elevation model. The coverage of rock fragments, fine sediments and mulch was quantified. Observations and descriptions of the soil profiles were restricted to the uppermost 50 cm. Vegetation properties were calculated using a Point Quadrat Method. The relationship between variables was evaluated through multivariate statistical analysis. The main results show the presence of 45 plant species distributed in 19 families, where shrubs are dominant. The wind effect, topographic wetness and dissection of the landscape are limiting factors of diversity. The coverage of superficial rock fragments influence vegetation coverage through the distribution and availability of rainwater. Furthermore, the different soil textures reveal that the silt content favors an increase in vegetation coverage. The presence of V horizon could condition the installation and development of vegetation in the early stages of growth.

Biomarker and stable carbon isotope analyses are presented for the Garau Formation of the Cretaceous Age, an important source rock in western Iran, to reveal its potential as an oil-prone source rock. The C₂₈/C₂₉ sterane ratio value range (0.72 to 0.83) of bitumen samples from the formation suggests that they were likely formed during phytoplankton blooms. Sterane, hopane, and isoprenoid/n-alkane ratios indicate that the formation's organic matter predominantly consists of algae, and bacteria, accompanied by some reworked material derived from higher plants. Due to the predominance of anoxic conditions and the actions of sulfate-reducing bacteria, the bitumen present is enriched with sulfur compounds. The percentages of saturates, aromatics, and nitrogen-sulfur-oxygen (NSO) fractions in the bitumen samples classify them as naphthenic oils. Isotope analysis reveals that biodegradation and water-washing have reduced the concentrations of some volatile saturates and low molecular weight aromatics in the bitumen samples. These actions have resulted in distinctive δ¹³C values for the formation's kerogen and bitumen fractions. The formation's organic matter has been subjected to high-temperature thermal regimes and has entered the oil-generation window at the sampled localities, with vitrinite reflectance (%R_C) varying between 0.7% and 0.75%.

Water level is the overriding control on carbon cycles in peatlands, which are important for global carbon cycles and ecosystem services. To date, our knowledge of the pattern of water level fluctuations in peatlands and the influence of precipitation and air temperature on them in the subtropical remains poor. In this study, we conducted continuous high-resolution monitoring of water levels from 2014 to 2021 in the Dajiuhu peatland, a typically subtropical peatland in central China. Monitoring results showed that the water level had strong annual (370 days) and seasonal (130 days) oscillations in the Dajiuhu peatland. The annual oscillation is associated with both precipitation and temperature, while the seasonal oscillation is mainly controlled by precipitation. In addition, the depth of peat surface to the water table (DWT) has weak but significant correlations with precipitation and temperature on the daily and weekly scales (r = 0.1–0.21, p < 0.01). Once replacing DWT with water table fluctuation cumulation, the correlation coefficients increase apparently (r = 0.47–0.69, p < 0.01), especially on the monthly scale. These findings highlight a more important role of the fluctuation than the mean position of water level and have the potential to improve the interpretation of water-level related paleoenvironmental proxies and the understanding of the relationship between water level and biogeochemical processes.

Research into metamorphism plays a pivotal role in reconstructing the evolution of continent, particularly through the study of ancient rocks that are highly susceptible to metamorphic alterations due to multiple tectonic activities. In the big data era, the establishment of new data platforms and the application of big data methods have become a focus for metamorphic rocks. Significant progress has been made in creating specialized databases, compiling comprehensive datasets, and utilizing data analytics to address complex scientific questions. However, many existing databases are inadequate in meeting the specific requirements of metamorphic research, resulting from a substantial amount of valuable data remaining uncollected. Therefore, constructing new databases that can cope with the development of the data era is necessary. This article provides an extensive review of existing databases related to metamorphic rocks and discusses data-driven studies in this. Accordingly, several crucial factors that need to be taken into consideration in the establishment of specialized metamorphic databases are identified, aiming to leverage data-driven applications to achieve broader scientific objectives in metamorphic research.

Fluid-rock interaction plays a critical function in physical and chemical processes associated with the formation and evolution of oil and gas reservoir space. In the diagenetic stage of shallow burial, the dissolution of carbonate rocks by acidic fluids is conducive to the development of secondary pore space in reservoirs. In contrast, the free drift experiment based on water bath instrument can simulate the dissolution process of carbonate rocks in shallow burial environment effectively. In order to study the shallow burial dissolution mechanism of carbonate rocks in different acid solutions, 14 samples of typical carbonate rocks of Sinian, Cambrian, Ordovician, Permian and Triassic ages in the Tarim and Sichuan basins, China were used. The dissolution experiments on carbonate rocks in sulfuric acid, acetic acid, hydrochloric acid, silicic acid and carbonic acid at shallow burial temperature (30 ℃ ≤ T ≤ 90 ℃) were carried out using a water bath instrument. The PHREEQC software was used to simulate the dissolution of carbonate minerals, in order to compare the results of constant temperature water bath experiment. The results show that acid solutions have significant dissolution effect on shallow burial carbonate rocks when T = 50–60 ℃, which corresponds to the burial depth of 1 500–2 000 m in the Tarim Basin and 1 110–1 480 m in the Sichuan Basin. However, there were obvious differences in the dissolution and reformation of carbonate rocks in different acids. In particular, sulfuric acid solution produced by thermochemical sulfate reduction can significantly promote the dissolution of carbonate rocks, especially dolomitic limestone. Moreover, the dissolution of limestone reservoirs is stronger than that of dolomite reservoirs in shallow burial. The results will provide new insights into the study of dissolution laws and influencing factors of reservoir spaces and the evaluation and prediction of carbonate reservoirs in China.

Mineralogical data are presented for the peridotite xenoliths from Miocene (~19 Ma) Qingyuan basalts in the eastern North China Craton (NCC), with the aim of constraining on property of the sub-continental lithospheric mantle (SCLM) beneath the northern Tan-Lu fault zone (TLFZ) during the Cenozoic. The Qingyuan peridotites are dominated by spinel lherzolites with moderate-Mg^# olivines (89.4 to 91.2), suggesting that the regional SCLM is mainly transitional and fertile. Light rare earth element (LREE)-depleted, slightly depleted and enriched clinopyroxenes (Cpx) are identified in different peridotites. Chemical compositions of the LREE-enriched Cpx and the presence of phlogopite suggest that the Qingyuan SCLM has experienced silicate-related metasomatism. The synthesis of available mineral chemical data of the mantle xenoliths across the NCC confirms the SCLM beneath the NCC is highly heterogeneous in time and space. The Mesozoic–Cenozoic SCLM beneath the TLFZ and neighboring regions are more fertile and thinner than that beneath the region away from the fault zone. The fertile and refractory peridotite xenoliths experienced varying degrees of silicate and carbonatite metasomatism, respectively. The spatial-temporal lithospheric mantle heterogeneity in composition, age and thickness suggest that the trans-lithosphere fault zone played an important role in heterogeneous replacement of refractory cratonic lithospheric mantle.

Composite granitic pluton with distinct units is a potential target for identifying its detailed magma evolution. Here, we present zircon U-Pb ages and Hf isotope, whole-rock major and trace element compositions and Nd-Pb isotopes of the Wangxiang composite pluton, South China. New ages obtained show that these rocks were generated in Late Jurassic (ca. 156–158 Ma). The rocks are divided into low silica (SiO₂ < 67 wt.%, biotite granodiorites and their dioritic enclaves) and high silica ones (SiO₂ > 71 wt.%, two-mica granites, garnet-bearing muscovite granites and muscovite granites). The high silica rocks are enriched in light rare earth elements (LREEs) relative to heavy REEs (HREEs) ((La/Yb)_N = 15.6–41.9, while the low silica rocks are not (0.7–76.6). All rocks show various negative Ti, Sr, Eu and strong positive Pb anomalies. The low silica rocks have less negative values of ε_Nd(t) (-8.79 to -6.99), similar values of (²⁰⁶Pb/²⁰⁴Pb)_i (18.155–18.346) and ε_Hf(t) (-9.51 to -3.47, except one -12.84), compared to the high silica rocks (ε_Nd(t) = -11.14 to -10.26; (²⁰⁶Pb/²⁰⁴Pb)_i = 17.935–19.093; ε_Hf(t) = -12.03 to -7.15, except one -2.41). Data suggest that the parental magma of the studied rocks (represented by enclaves) was produced by partial melting of a garnet-free crustal source. Subsequently those crustal magmas formed the more evolved units through assimilation and fractional crystallization processes, and fluid enrichment during the final magmatic activity. Combining our results with previous multidisciplinary studies, we propose that the key factor to control the evolution of Wangxiang composite pluton is discrete emplacement of crustal magmas by dyking.

Field- and petrographic investigations, together with microanalytical major- and trace-element studies, were carried out on clinopyroxene and amphibole from high-Mg diorite in the subduction-related Chelyabinsk granitic massif to understand its petrogenesis and source. The clinopyroxene composition (high Mg#, Cr-content, sum of REE and Ti/Eu ratio; depletion in HREE; negative Eu-anomaly) indicates that it formed from a reduced melt derived from a mantle source metasomatized by fluids/melts having crustal affinity. Melt compositions in equilibrium with clinopyroxene and amphibole were calculated using solid/liquid partition coefficients. The high Nb/Y and Zr/Y ratio values of a liquid simulated from clinopyroxene, which appears to have very similar characteristics to sanukitoid melts, indicate a low degree of melting of the mantle source. Melt simulated from amphibole is more evolved and more felsic (dacitic). It displays a geochemical "amphibole fractionation" signature, indicating the peritectic transformation of clinopyroxene to amphibole in the lower crust. Rock textures and major element mineral compositions suggest that further amphibole was precipitated directly from the melt in the middle crust. The results show that the Chelyabinsk high-Mg diorite was probably formed as a cumulate from sanukitoid-like melt during its ascent and cooling below dacitic liquidus inside the amphibole stability field.

The Song Chay Dome in southeastern Yunnan Province, China, is intruded by the Late Cretaceous Laojunshan granites. New apatite and zircon fission-track data for the Laojunshan granites allow us to reconstruct the exhumation history of the Song Chay Dome. The fission-track dating indicates that the Laojunshan granites experienced four main stages of rapid cooling and exhumation at 75–63, 53–43, 31–20, and 12–4 Ma. The first stage was related to the thermal equilibration with surrounding rocks after magma emplacement. The rapid cooling and exhumation at 53–43 Ma were caused by normal faulting in the Late Mesozoic–Early Cenozoic extensional setting of southwestern South China, which resulted in the Laojunshan granites and Song Chay Dome being exhumed in the footwall of faults. The third stage (31–20 Ma) was the result of southeastward extrusion of the Tibetan Plateau and sinistral strike-slip movement on the NW-SE-trending Nanwenhe and Maguan-Dulong faults. The 31 Ma representing the beginning of the interaction between the Tethyan Himalayan tectonic domain and the South China Block. The final stage was mainly due to activity on the Nanwenhe Fault to the north of the Laojunshan granites, caused by lateral extrusion of the southeastern Tibetan Plateau since ca. 15 Ma. These cooling and exhumation events since the Late Cretaceous indicate that the Song Chay Dome and southwestern South China Block have been affected by the Himalayan Orogeny since the Oligocene.

This study investigates the mineralogy and mineral-chemistry of a newly discovered Au-Ag-Bi-Te mineralization at the Aydindere Fe-Cu skarn deposit, within the Pontides Tectonic Unit, northeastern Turkey. The mineralization is developed in the skarn zone at the contact between Upper Cretaceous andesite-pyroclastic rocks and a Paleocene–Eocene Ⅰ-type granitoid. The principal ore minerals of the Aydindere Fe-Cu deposit are oxides (magnetite), sulfides (pyrite-chalcopyrite-galena-sphalerite), tellurides/sulfotellurides (tetradymite, hessite), sulfosalts (wittichenite, emplectite, aikinite) and native gold-electrum. Skarn minerals include anhydrous phases (garnet) formed in a prograde stage and hydrous phases (amphibole, epidote, chlorite), which were formed in a retrograde stage in association with quartz, adularia, apatite and late calcite. Sulfides, tellurides and sulfosalts are introduced during the retrograde stage. The Au-Ag-Bi-Te mineralization was detected for the first time within the western ore body of the Aydindere deposit, and occurs in calcite-bearing sulfide bodies that cut magnetite-garnet-amphibole-epidote skarns with magnetite ores of different grade, including massive magnetite. Chlorite geothermometry indicates formation of the Au-Ag-Bi-Te mineralization at temperatures between 300 and 250 ℃, during the retrograde skarn evolution. Assuming the temperature is ~275 ℃, logfS₂ = -10.5 to -13, logfO₂ = -37 to -33, and logfTe₂ values range from approximately -12 to -8.5 were estimated. The available mineralogical and geological data (presences of magnetite, oxidized-type tellurides/sulfotellurides, and andraditic garnets, and absence of pyrrhotite and arsenopyrite) suggest that Aydindere is an oxidized Au-bearing skarn deposit. The discovery of Au-Ag-Bi-Te mineralization at Aydindere increases its productivity and requires more detailed exploration in the deposit for precious (Au, Ag) and critical (Bi, Te) metals.

The complex plate collision process led the South Yellow Sea Basin (SYSB) to go through an intensity tectonic inversion during the Early Cenozoic, leading to a regional unconformity surface development. As a petroliferous basin, SYSB saw intense denudation and deposition processes, making it hard to characterize their source-to-sink system (S2S), and this study provided a new way to reveal them quantitatively. According to the seismic interpretation, it was found that two types of tectonic inversion led to the strata shortening process, which was classified according to their difference in planar movements: dip-slip faults and strike-slip ones. As for dip-slip faults, the inversion structure was primarily formed by the dip-slip movement, and many fault-related folds developed, which developed in the North Depression Zone of the SYSB. The strike-slip ones, accompanied by some negative flower structures, dominate the South Depression Zone of the SYSB. To reveal its source-to-sink (S2S) system in the tectonic inversion basin, we rebuild the provenance area with detrital zircon U-Pb data and heavy mineral assemblage. The results show, during the Eocene (tectonic inversion stage), the proximal slump or fan delta from the Central Uplift Zone was prominently developed in the North Depression Zone, and the South Depression Zone is filled by sediments from the proximal area (Central Uplift Zone in SYSB and Wunansha Uplift) and the prograding delta long-axis parallel to the boundary faults. Then, calculations were conducted on the coarse sediment content, fault displacements, catchment relief, sediment migration distance, and discussions about the impact factors of the S2S system developed in various strata shortening patterns with a statistical method. It was found that, within the dip-slip faults-dominated zone, the volume of the sediment routing system and the ratio of coarse-grained sediments merely have a relationship with the amount of sediment supply and average faults break displacement. Compared with the strike-slip faults-dominated zone, the source-to-sink system shows a lower level of sandy sediment influx, and its coarse-grained content is mainly determined by the average faults broken displacement.

The Songliao Basin in northeast China is one of the largest petroliferous basins worldwide, and features the T₂ fault system, which consists of numerous minor extensional normal faults. This study combines high-resolution 3D seismic datasets to detail the characteristics of the T₂ fault system, contributing two key findings: (1) The T₂ faults are confirmed as polygonal fault systems, characterized by closely spaced, layer-bounded faults with small throws, high dip angles, and random orientations, forming intricate polygonal networks. (2) The study reveals the influence of tectonic stresses on the fault system, showing spatial variations across different tectonic units. In depressions, T₂ faults exhibit short lengths, small throws, high density, and multiple directions. In contrast, in inverted anticline belts, they have longer lengths, bigger throws, higher density, and concordant orientations. These variations demonstrate the impact of tectonic inversion on the development of T₂ faults. The significance of this research lies in presenting a typical polygonal fault system developed in a deep lake succession and was superposed the influence by regional tectonic stress coeval with its development. The new insights facilitate a reevaluation of the T₂ fault system's role in hydrocarbon migration and accumulation within the Songliao Basin.

The black shale samples from the Niutitang Formation in the Yangtze Block were sequentially treated using organic solvent extraction and wet chemical oxidation. The organic matter (OM) in the shales includes physically mobile OM (PmOM), chemically mobile OM (CmOM), and stable OM (StOM). The CmOM has the strongest CH₄ adsorption capacity because it has the largest volume of micropores and mesopores. In contrast, the PmOM has a very negative effect on the CH₄ adsorption because it is poreless. The XD shale is a siliceous shale, in which the quartz particles wrap partly OM, preventing extraction and oxidation. The SL shale is an argillaceous shale, in which most of the OM is combined with clay minerals to form organo-clay composites. In both the SL and XD shales, the OM that is extractable via organic solvents is distributed among the mineral particles and is interconnected. The conceptual model of marine black shale in different environments needs to be perfected in the future because quantitative and qualitative methods should be combined to clarify the relationship between the known OM types (e.g., pyrobitumen, solid bitumen, and solid kerogen) and the OM types identified in this study.

The northwestern margin of Junggar Basin is the region with the richest oil sand resources in China. For better understanding the enrichment rules and deployment of exploration and development of regional oil sand, it is of great scientific significance to study the accumulation conditions of oil sand in different strata and mining areas of the Junggar Basin. Through a large number of field investigations, drilling verification and sampling tests, it is found that the oil sand in the region covers an area of 2 000 km², with shallow and thick reservoir, and predicted resource of 180 million tons. The oil sand resources are mainly distributed in four geological strata, namely the Middle Triassic Karamay Formation, Early Jurassic Badaowan Formation, Late Jurassic Qigu Formation, and Early Cretaceous Qingshuihe Formation. The reservoir is mainly composed of sandstone with high porosity and permeability, and the reservoir space is mainly intergranular pores with a medium average oil content. The oil sand deposit in the region is a typical destructive oil reservoir. The crude oil in the oil sand layer is degraded and thickened from the deep to the shallow, the content of saturated hydrocarbon decreased, and the content of aromatic hydrocarbon, non-hydrocarbon and asphaltene increased. The oil source comes from the deep Permian hydrocarbon-generating depression. Unconformities, faults and marginal fan delta-braided river depositional systems constitute effective migration and storage systems. Caprocks of the Upper Triassic Baijiantan Formation, Lower Jurassic Sangonghe Formation and Lower Cretaceous Hutubihe Formation were formed by three large scale lake transgressions. The Indosinian, Yanshan and Late Yanshan movements are the main driving forces for the migration of deep oil and gas to the shallow edge to form oil sand deposits. It is considered that the oil sand in the northwestern margin of Junggar Basin is of a slope complex migration type.

This paper is a synthetic use of carbon isotope composition, Rock-Eval data, organic petrology, element composition of kerogen, major and trace elements, and biomarker characteristic of the Permian Pingdiquan (P₂p) source rocks in the Wucaiwan sag, Junggar Basin, China as proxies (1) for evaluations of hydrocarbon potential, organic matter (OM) composition and thermal maturity of the OM in the source rocks, (2) for reconstruction of paleodepositional environment, and (3) for analysis of controlling factor of organic carbon accumulation. The P₂p Formation developed good-excellent source rocks with thermal maturity of OM ranging from low-mature to mature stages. The OM was mainly composed of C₃ terrestrial higher plants and aquatic organisms including aerobic bacteria, green sulfur bacteria, saltwater and fresh algae, Sphagnum moss species, submerged macrophytes, Nymphaea, and aquatic pollen taxa. The proportion of terrestrial higher plants decreased and that of aquatic organisms increased from margin to center of the sag. The benthic water within reducing environment and brackish-water column were superposed by periodic/occasional fresh-water influx (e.g., rainfall and river drain), which led to fresh-water conditions and well oxygenating in the water column during overturn process. The whole study area developed lacustrine source rocks without seawater intrusion. During periodic/occasional fresh-water influx periods with plenty of terrestrial plant inputs, the paleoredox conditions of the sag were relatively oxic in the shallow fresh-water which experienced strong oxidation and decomposition of OM, therefore were not conducive for the OM preservation. However, the overall middle primary productivity made up for this deficiency, and was the main controlling factor on the organic carbon accumulation. A suitable supply from terrestrial inputs can promote biotic paleoproductivity, and a relatively high sedimentation rate can reduce oxidation and decomposition times of OM. On the contrary, during the intervals of the fresh-water influxes, relatively reducing conditions are a more important controlling factor on the OM accumulation in the case that the decrease of the terrestrial biotic source.

The joint roughness coefficient (JRC) is one of the key parameters for evaluating the shear strength of rock joints. Because of the scale effect in the JRC, reliable JRC values are of great importance for most rock engineering projects. During the collection process of JRC samples, the redundancy or insufficiency of representative rock joint surface topography (RJST) information in serial length JRC samples is the essential reason that affects the reliability of the scale effect results. Therefore, this paper proposes an adaptive sampling method, in which we use the entropy consistency measure Q(a) to evaluate the consistency of the joint morphology information contained in adjacent JRC samples. Then the sampling interval is automatically adjusted according to the threshold Q(a_t) of the entropy consistency measure to ensure that the degree of change of RJST information between JRC samples is the same, and ultimately makes the representative RJST information in the collected JRC samples more balanced. The application results of actual cases show that the proposed method can obtain the scale effect in the JRC efficiently and reliably.

Landslides frequently occurred in Jurassic red strata in the Three Gorges Reservoir (TGR) region in China. The Jurassic strata consist of low mechanical strength and poor permeability of weak silty mudstone layer, which may cause slope instability during rainfall. In order to understand the strength behavior of Jurassic silty mudstone shear zone, the so-called Shizibao landslide located in Guojiaba Town, Zigui County, Three Gorges Reservoir (TGR) in China is selected as a case study. The shear strength of the silty mudstone shear zone is strongly influenced by both the water content and the normal stress. Therefore, a series of drained ring shear tests were carried out by varying the water contents (7%, 12%, 17%, and 20%, respectively) and normal stresses (200, 300, 400, and 500 kPa, respectively). The result revealed that the residual friction coefficient and residual friction angle were power function relationships with water content and normal stress. The peak cohesion of the silty mudstone slip zone increased with water content to a certain limit, above which the cohesion decreased. In contrast, the residual cohesion showed the opposite trend, indicating the cohesion recovery above a certain limit of water content. However, both the peak and residual friction angle of the silty mudstone slip zone were observed to decrease steadily with increased water content. Furthermore, the macroscopic morphological features of the shear surface showed that the sliding failure was developed under high normal stress at low water content, while discontinuous sliding surface and soil extrusion were occurred when the water content increased to a saturated degree. The localized liquefaction developed by excess pore water pressure reduced the frictional force within the shear zone. Finally, the combined effects of the slope excavation and precipitation ultimately lead to the failure of the silty mudstone slope; however, continuous rainfall is the main factor triggering sliding.

To reduce the uncertainty associated with the traditional definition of tunnel boring machine (TBM) utilization (U) and achieve an effective indicator of TBM performance, a new performance indicator called rock mass-related utilization (U_r) is introduced; this variable considers only rock mass-related factors rather than all potential factors. This work aims to predict U_r by adopting the rock mass rating (RMR) and the moisture-dependent Cerchar abrasivity index (CAI). Substantial U_r, RMR and CAI data are acquired from a 31.57 km northwestern Chinese water conveyance tunnel via tunnelling field recordings, geological investigations and Cerchar abrasivity tests. The moisture dependence of the CAI is explored across four lithologies: quartz schists, granites, sandstones and metamorphic andesites. The potential influences of RMR and CAI on U_r are then investigated. As the RMR increases, U_r initially increases and then peaks at an RMR of 56 before declining. U_r appears to decline with CAI. An investigation-based relation among U_r, RMR and moisture-dependent CAI is developed for estimating U_r. The developed relation can accurately predict U_r using RMR and moisture-dependent CAI in the majority of the tunnelling cases examined. This work proposes a stable indicator of TBM performance and provided a fairly accurate prediction method for this indicator.

The constitutive model is essential for predicting the deformation and stability of rock-soil mass. The estimation of constitutive model parameters is a necessary and important task for the reliable characterization of mechanical behaviors. However, constitutive model parameters cannot be evaluated accurately with a limited amount of test data, resulting in uncertainty in the prediction of stress-strain curves. This paper proposes a Bayesian analysis framework to address this issue. It combines the Bayesian updating with the structural reliability and adaptive conditional sampling methods to assess the equation parameter of constitutive models. Based on the triaxial and ring shear tests on shear zone soils from the Huangtupo landslide, a statistical damage constitutive model and a critical state hypoplastic constitutive model were used to demonstrate the effectiveness of the proposed framework. Moreover, the parameter uncertainty effects of the damage constitutive model on landslide stability were investigated. Results show that reasonable assessments of the constitutive model parameter can be well realized. The variability of stress-strain curves is strongly related to the model prediction performance. The estimation uncertainty of constitutive model parameters should not be ignored for the landslide stability calculation. Our study provides a reference for uncertainty analysis and parameter assessment of the constitutive model.

Benefit evaluation of debris flow prevention and control projects was one of the essential contents of debris flow prevention and mitigation work. In order to scientifically and quantitatively evaluate the comprehensive benefit of debris flow prevention and control projects, this study identified nine factors as evaluation indicators from economic, social, and ecological aspects. The projection pursuit (PP) model based on the improved particle swarm optimization (IPSO) algorithm was used to construct a mathematical model to evaluate the benefit of debris flow prevention and control projects. The interpolation method was applied to divide the benefit grades. The debris flow prevention and control projects in Qipan, Taoguan, Chutou, Anjia, and Mozi gullies in Wenchuan County were chosen as typical cases for empirical analysis. The case study revealed that, among the criteria layer indicators, investment per unit of the protected area, investment per unit of the protected population, the amount of water and soil conservation, and reduction rate of accumulation fan had the most significant weights. The social and ecological benefits were found to be the more important in the target layer. The comprehensive benefit of Qipan, Taoguan, Chutou, Anjia, and Mozi gullies was found to be 4.44, 4.83, 1.95, 3, and 2, respectively. The benefit ranking of the five gullies was consistent with their effectiveness in disaster prevention ranking in the flood season of 2019. Therefore, it could prove that the newly-built benefit evaluation model was practical and feasible, and the evaluation results of the sample could be reasonably interpreted, which verified the effectiveness of the methods.

Slow-moving landslides are widespread in the Mediterranean area, causing damage to the exposed facilities and economic losses in many countries. The recognition of slow-moving landslides in urban areas is always a difficult task to deal with because the presence of buildings, infrastructures, and human activities usually conceals the morphological signs of these landslide activities. So, in the last decades, numerous researchers have shown new methodologies to deepen the studies of similar instability phenomena. The present research is based on an integrated approach to investigate the landslide boundaries, type of movement, failure surface depth, and vulnerability state of buildings in Rota Greca Village (Calabria region, southern Italy) affected by a slow-moving landslide. For this purpose, multi-source data were acquired through geological and geomorphological surveys, recognition of landslide-induced damage on the built environment, subsurface investigations (e.g., continuous drill boreholes, Standard Penetration Test, Rock Quality Designation index and inclinometer monitoring), laboratory tests (direct shear tests on undisturbed samples), geophysical survey, and InSAR-derived map of deformation rates. The complete integration of multi-source data allowed for the construction of reliable landslide modelling with relative geotechnical properties. In addition, the cross-comparison between surface deformation data by SAR images and severity damage level collected on the exposed buildings enabled to obtain the vulnerability map of the built area. In particular, the achieved goals highlighted two failure surfaces at about -13 and -25 m depth, causing a high vulnerability value for the buildings allocated in the central portion of the Rota Greca Village. The knowledge acquired by the multi-approach can be used to manage and implement appropriate landslide risk mitigation strategies, providing helpful advice and best practices to state-run organisations and stakeholders for landslide management in urban sites.

Massive granitic rock avalanches are extensively developed in the middle section of the northern Qinling Mountains (NQM), China. The current consensus is that their formation could have been connected with seismic events that occurred in the NQM. However, there is a lack of systematic discussion on the genetic dynamics of these rock avalanches. Hence, taking Earth system scientific research as a starting point, this paper systematically summarizes and discusses development characteristics, formation times and genetic dynamic mechanisms of granitic rock avalanches in the NQM based on geological investigations, high-precision remote sensing interpretations, geomorphological dating, geophysical exploration, and a large-scale shaking table model test. We identified 53 granitic rock avalanches in this area, with a single collapse area ranging from 0.01 × 10⁶ to 1.71 × 10⁶ m². Their development time can be divided into six stages, namely, 107 000 years BP, 11 870–11 950 years BP, 11 000 years BP, 2 300 years BP, 1 800 years BP, and 1 500 years BP, which were closely related to multiple prehistoric or ancient earthquakes. We suggest that long-term coupling of internal and external earth dynamics was responsible for the granitic rock avalanches in the NQM; the internal dynamics were mainly related to subduction, collision and extrusion of different plates under the Qinling terrane, leading to the formation and tectonic uplift of the Qinling orogenic belt; and the external dynamics were closely associated with climate changes resulting in mountain denudation, freeze-thaw cycles and isostatic balance uplift. In this process, the formation and evolution of the Qinling orogenic belt play a geohazard-pregnant role, structural planes, including faults and joints, play a geohazard-controlled role, and earthquakes play a geohazard-induced role, which jointly results in the occurrence of large-scale granitic rock avalanches in the NQM. This research can not only decipher the genetic dynamic mechanism of large hard granitic rock avalanches but also reveal temporal and spatial patterns of the evolution of breeding and the generation of large-scale rock avalanches in the margins of orogenic belts.

Source identification and deformation analysis of disaster bodies are the main contents of high-steep slope risk assessment, the establishment of high-precision model and the quantification of the fine geometric features of the slope are the prerequisites for the above work. In this study, based on the UAV remote sensing technology in acquiring refined model and quantitative parameters, a semi-automatic dangerous rock identification method based on multi-source data is proposed. In terms of the periodicity UAV-based deformation monitoring, the monitoring accuracy is defined according to the relative accuracy of multi-temporal point cloud. Taking a high-steep slope as research object, the UAV equipped with special sensors was used to obtain multi-source and multi-temporal data, including high-precision DOM and multi-temporal 3D point clouds. The geometric features of the outcrop were extracted and superimposed with DOM images to carry out semi-automatic identification of dangerous rock mass, realizes the closed-loop of identification and accuracy verification; changing detection of multi-temporal 3D point clouds was conducted to capture deformation of slope with centimeter accuracy. The results show that the multi-source data-based semi-automatic dangerous rock identification method can complement each other to improve the efficiency and accuracy of identification, and the UAV-based multi-temporal monitoring can reveal the near real-time deformation state of slopes.

Studying the inner structure of intraplate earthquakes originating in aseismic areas, which are poorly covered by seismic networks or as historical earthquakes is usually the only way to get knowledge about their source mechanisms, which is partially essential for a deeper understanding of intraplate geodynamics. The epicentral zones of earthquakes are situated in hard-to-reach areas, so, using active seismic methods for such purposes is unreasonable or even impossible because of high cost and logistical difficulties. We propose a novel approach that combines diverse passive seismic methods, which allows us to get sufficient information about geological environment structure for such task solutions. As an example, we investigated the inner structure of platform earthquake epicentral zone originated up north of Russia. We used four passive seismic methods: microseismic sounding method, passive seismic interferometry, HVSR method, and microseismic activity method. We show that passive seismic data, recoded in the same installation and processed by these different methods, can provide sufficient information about structure of studied environment, needed to explain source mechanism. In sum, the hypocenter zone is presented by intersection of vertical faults and a lateral fractured zone in the middle crust. Results were confirmed by comparison with results by active seismic methods.

On May 22, 2021, an M_S7.4 earthquake occurred in Maduo County, Qinghai Province, on the western plateau of China. The level of seismic monitoring in this area was inadequate, and incomplete seismic waveforms were obtained from a few broadband seismometers located within 300 km of the epicentre. All waveforms showed "truncation" phenomena. The waveforms of earthquakes can guide ground motion inputs in near-fault areas. This paper uses the empirical Green's function method to consider the uncertainties in source parameters and source rupture processes by synthesizing high-probability, accurate waveforms in Maduo County (MAD station) near the epicentre. The acceleration waveform at the DAW strong-motion station, located 176 km from the epicentre, is first synthesized with the observed waveform of the mainshock. This critical step not only provides a more accurate source and rupture model of the Maduo earthquake but also establishes an essential reference standard. Secondly, the inferred models are rigorously applied to synthesize the acceleration waveform of the MAD station, ensuring that the results maintain a high accuracy and probability. The findings suggest that (1) the simulated acceleration waveform for the MAD station can better characterize the actual ground motion characteristics of the M_S7.4 earthquake in Maduo County, with high accuracy and probability in peak ground acceleration (Abbreviated as PGA) ranges of 140–240 and 350–390 cm/s², respectively, and (2) the M_S7.4 earthquake did not undergo a complete supershear rupture process. The first asperity located on the east side of the epicentre is most likely to undergo supershear rupture. However, the Maduo earthquake may have been a complete subshear rupture. (3) The fault dislocation model of the three-asperity model better matches the actual source rupture process of the Maduo earthquake. This method can provide relatively accurate acceleration waveforms for regions with limited earthquake monitoring capabilities and assist in analysis of building seismic damage response, earthquake-induced geological disasters and sand liquefaction, and estimation of regional disaster losses.