Bailong River Basin is one of the most developed and serious areas of debris flow disaster chain in China. In order to support and serve the disaster prevention and mitigation of the large geological chain in Bailong River Basin, the debris flow in Zhaizigou, Zhouqu County, Gansu Province, was selected as the research object. Through on-site survey and mapping, combined with multi-period remote sensing data, laboratory test and numerical simulation results, the development characteristics, formation conditions and evolution model of debris flow were discussed in depth. Finally, the paper puts forward some suggestions on preventing the risk of debris flow disaster chain.The results show that: Zhaizigou is a gully type debris flow, the longitudinal slope of the gully bed is 324.5‰, and the high level source amount is 2129.23×10⁴ m³. The key disaster landform of Zhaizigou is unique, the necessary disaster formation and disaster control structure are complex, and the important triggering conditions are obvious, which has all the conditions for the occurrence of a huge debris flow disaster chain. The evolution model of the disaster chain is the disaster chain of high level collapse-barrier body collapse-debris flow, barrier lake and outburst flood. On this basis, it is proposed that the risk prevention and control of the disaster chain of the huge mudflow in Bailong River basin should focus on strengthening the disaster chain investigation and identification ability, tackling the key disaster chain monitoring, early warning, forecasting and risk prevention and control technology, and strengthening the disaster chain project disaster prevention and reduction and emergency disposal capacity. Finally, according to the characteristics and key problems of different risk areas from the perspective of river basin, the risk prevention and control model of Zhaizigou debris flow disaster chain risk prevention and control is constructed, which can provide reference for the disaster prevention and reduction of similar massive debris flow disaster chain in western mountainous areas.

This study aims to unravel the genetic mechanism governing the high-angle sharp bends of the Yellow River channel that cut across mountain ranges within the Lanzhou–Zhongwei Shapotou reach on the northeastern margin of the Tibetan Plateau, as well as to clarify the controlling effects of fault structures on the formation and long-term evolution of the river channel. Integrating field geological surveys, remote sensing interpretation, and regional geological analysis with tectonic geomorphology, this study focused on the geological structural characteristics of the two representative high-angle bend segments at Luoquanwan in Lanzhou and Wufo Township in Jingtai. The distribution and activity properties of fault systems were analyzed to evaluate their impacts on the spatial alignment of the Yellow River channel. Our results demonstrate that the Lanzhou–Zhongwei reach of the Yellow River is predominantly aligned along NE-, NEE-, and NW-trending fault zones, with particularly strong control exerted by NE-trending extensional strike-slip faults. These faults represent the key structural driver that facilitated river incision through mountain ranges and triggered channel avulsions. At both Luoquanwan and Wufo Township, the river did not follow the pre-existing NW–SE trending piedmont depression zones for natural downstream propagation, instead, it developed near right-angle sharp bends and cut across or obliquely traversed the NW-SE trending mountain ranges. The Yellow River channel predominantly develops within tectonic junctions and structural fracture zones formed by regional faults. The intersection, strike-slip, and thrusting of NE-trending and NW–NWW-trending faults collectively contribute to the short-line, high-angle bends of the river channel and its traversal of topographically elevated mountain systems. The Yellow River channel is primarily developed within tectonic junctions and structural fracture or fault crush zones formed by regional fault systems. Fault structures are the dominant controlling factor governing the channel extension and bending, particularly in driving the river to deviate from its original main course direction, dissect mountains, and traverse or obliquely cut across mountain systems via short-line, high-angle bends.

The ocean-continent pattern, sedimentary tectonic evolution and the relationship between adjacent blocks in the Qin-Qi-He crosslinking area on the southwest margin of the North China Craton since the Early Paleozoic have been the focus of research in recent years. In this paper, LA-ICP-MS zircon U-Pb geochronological analysis is used to analyze a set of coarse clastic molarite sedimentary rocks, which were previously thought to belong to Silurian and Devonian but lack of fossil records, from Xianghuanggou section in Nanhuashan area, northeastern margin of the North Qilian tectonic belt. Clastic rock samples were collected and detrital zircon U-Pb dating analysis was performed. The results show that the U-Pb concordant age of the youngest zircon is 230.2±2.6 Ma, and the concordant age of several younger zircons is 232±5 Ma, 232±3 Ma and 236.7±2.4 Ma, respectively. U-Pb weighted age of the youngest zircon is 233.2±5.1 Ma, and the earliest depositional age of the host strata is the Late Triassic. Combined with the age spectrum of detrital zircons from the adjacent stratigraphic units, it is concluded that the main body of the molarite sedimentary strata in the study area belongs to the Upper Triassic sedimentary stratigraphic units. It does not support the traditional understanding of the Silurian Devonian system in the past. According to the comparative analysis of regional age spectrum, the Late Triassic coarse clastic molarite sedimentary rocks in Xianghuanggou section of Nanhuashan Mountain are mainly derived from the North Qinling and Alxa areas in the Early Mesozoic, and the Qilian-North Qinling areas in the Early Paleozoic. The source of Precambrian detrital material is a bidirectional mixture source between the North China plate and the Qilian-North Qinling orogenic belt. The conglomerate deposits were mainly controlled by the tectonism of the Qin-Qi collisional orogenic belt in the Indosinian period, and should belong to the sedimentary tectonic response of the final collisional closure process of the Qin-Qi trough in the Indosinian period.

The Carboniferous strata in the northwestern margin of the Junggar Basin represent an important target for deep hydrocarbon exploration, with the characteristics and formation background of source rocks attracting significant attention. This study focuses on the dark mudstones of the Carboniferous strata in Well MH55, utilizing systematic sampling and organic-inorganic geochemical analyses to investigate their hydrocarbon potential, paleo-depositional environment, and organic matter enrichment mechanisms. The results reveal that the organic matter content in the dark mudstones of Well MH55 is moderate, dominated by Type Ⅲ kerogen. The source rocks exhibit a high degree of thermal maturity with significant fluctuations, likely influenced by frictional heating associated with fault activity, and are overall classified as poor-to-moderate source rocks. The mudstones were deposited in a brackish-to-saline transitional environment characterized by dysoxic water conditions and oscillating climatic shifts between warm-humid and cold-arid periods. Organic matter enrichment was primarily controlled by terrigenous input and dysoxic conditions. Terrigenous input provided the primary source of organic matter, while dysoxic conditions effectively reduced organic matter oxidation and decomposition rates. In contrast, the contribution of paleo-productivity was relatively limited, which may be attributed to insufficient nutrient availability in the water column and dilution effects from terrigenous material input during deposition.

The Mayidang, Tu'erkuli, Keyinnan and other graphite deposits in the Moqinwula area of the East Junggar Basin, Xinjiang, are newly discovered deposits with industrial value in recent years. Taking the Tu'erkuli graphite Deposit as the research object, this study carried out LA-ICP-MS zircon U-Pb dating and petrogeochemical analysis. Chronological results show that the ore-hosting stratum of this deposit formed at 334±9 Ma, and the graphite mineralization occurred at 313 Ma. The petrogeochemical characteristics are as follows: the graphite ore is enriched in lithophile elements such as Rb, Ba, Pb and Sr, and depleted in high field strength elements (HFSEs) including Th, Nb, Ta and Ti; the total content of rare earth elements (REEs) is relatively low, with ΣREE ranging from 52.16×10⁻⁶ to 134.21×10⁻⁶ and an average of 81.71×10⁻⁶. These features indicate that the sedimentary materials of the ore-bearing rocks were derived from terrigenous clastic rocks, and the rocks formed in a neritic-epicontinental anoxic reducing sedimentary environment. Comprehensive research suggests that the ore-hosting stratum of graphite deposits in the Moqinwula area of East Junggar is the Lower Carboniferous Jiangbasitao Formation, which corrects the previous understanding that it belonged to the Upper Silurian-Lower Devonian Hongliugou Formation. This deposit is a contact metamorphic graphite deposit. Its genetic mechanism is as follows: under the superimposed transformation of late tectonic activities and magmatic intrusion, the organic matter in the carbon-bearing sedimentary rock series of the Lower Carboniferous Jiangbasitao Formation was activated, undergoing deoxidation and dehydrogenation reactions followed by recrystallization, and finally forming crystalline graphite.

The Xinjie Taigemiao mining area of Dongsheng Coalfield contains rich coal resources, which is located in the Ejin Horo Banner and Wushen Banner, Ordos City, Inner Mongolia Autonomous Region. However, the coal quality has not been comprehensively evaluated at present, which seriously restricts the clean and efficient utilization of coal resources in the future. Based on the abundant geological exploration data, we comprehensively analyzes the coal quality and coal rock characteristics of the Yan'an Formation coal in the Xinjie Taigemiao mining area. Combined with the classification of coal cleanliness levels and the evaluation index system of various coal clean utilization directions, the clean potential and clean utilization direction of the Yan'an Formation coal in the Taigemiao mining area are comprehensively evaluated. The results show that the Yan'an Formation coal in the Taigemiao mining area has the characteristics of ultra-low ash, ultra-low low sulfur, low harmful elements, and high calorific value. These characteristics indicate that the Yan'an Formation coal is high-quality, high cleanliness power coal, and is comprehensively evaluated as Class II power coal. The characteristics of high tar yield (generally＞7%), medium high volatile matter, high fixed carbon, ultra-low ash content, and low moisture content indicate that it is suitable for low-temperature pyrolysis extraction of coal tar (Class I). In addition, its cohesiveness, low moisture content, high hydrogen to carbon atomic ratio, and high inertinite contents, indicate that it is also suitable for liquefaction coal. Based on the development planning goals of the mining area, we proposed that the Yan'an Formation coal in the Taigemiao mining area has a high potential for clean energy, and the advantageous utilization directions are clean power coal and coal for tar production.

The Gufang-Yangying area in the southeast of Fengning Manchu Autonomous County, Hebei Province, is located at the northern margin of the North China Craton, tectonically situated at the junction between the northern margin uplift belt of the North China Craton and the Chengde North Basin of the Yanshan-Liaoxi rift zone, adjacent to the Shangyi-Longhua regional fault. The area is dominated by metamorphic rock series of the Neoarchean Upper Chongli Group (Yangying and Aijiagou formations), with complex structures, well-developed folds, and iron deposits primarily consisting of sedimentary-metamorphic iron ore and ultra-poor magnetite, generally positioned along northeast-trending tight synclinal structures. Although previous geophysical surveys have been conducted, large-scale high-precision ground magnetic measurements remain insufficient, resulting in inadequate delineation of three-dimensional deep ore body structures and constraining deep prospecting efforts. This study, based on 1∶5000 high-precision ground magnetic survey data, employs reduction to pole, variable-height upward continuation, field separation, analytical signal, vertical derivative, and tilt derivative processing, combined with rock physical property statistics, and utilizes the open-source SimPEG framework for three-dimensional magnetic susceptibility inversion to reveal the spatial distribution characteristics of magnetic bodies within a 1 km depth range; rock physical properties indicate significant magnetic contrast between mineralized iron-bearing rocks and host rocks, providing a robust foundation for magnetic exploration. Inversion results show that magnetic bodies are distributed in a northeast-southwest trending strip-like pattern, mainly concentrated in the central-eastern and southwestern parts, highly consistent with known surface ore bodies and the Upper Chongli Group metamorphic series; vertically, they exhibit scattered distribution in shallow depths, concentrated and continuous in middle depths, and rapid weakening in deeper levels, with three-dimensional displays at different susceptibility thresholds further confirming that high-susceptibility zones are predominantly in the central-eastern part, forming large lens-shaped bodies that partially extend close to the surface, reflecting progressive thickening and enlargement of ore bodies along dip directions. The study confirms that sedimentary-metamorphic iron deposits in the area are controlled by Neoarchean regional metamorphism, conforming to the typical BIF-type metallogenic model at the northern margin of the North China Craton; high-precision three-dimensional susceptibility inversion effectively addresses the knowledge gap in deep structures under complex geological conditions, providing high-resolution geophysical evidence for precise localization of concealed ore bodies, with the central-eastern high-susceptibility zone representing the most favorable target for deep prospecting and warranting priority for drilling verification. These findings deepen understanding of deep metallogenic elements in the study area and offer reliable technical approaches and integrated geological-geophysical methodologies for deep prediction in similar sedimentary-metamorphic iron ore districts along the northern margin of the North China Craton.

Ecology-supporting sphere is an important part of natural resources, and it is the basic material that supports and nurtures various natural resources and ecological environment. Taking Ningxiang City as an example, this paper constructs a cultivated land suitability evaluation system with 10 evaluation indexes from the surface form, physical and chemical properties, and internal structure, and analyzes the existing cultivated land resources on the basis of serving the construction of ecological civilization. The results showed that: ① In general, Ningxiang City had a high suitability level of cultivated land, and the suitable area was about 1 164.67 km² accounting for 40.08%. The suitability level showed a distribution trend of high in the east and low in the west. ② Superimposing the land use status, it is found that the cultivated land of suitable grade is concentrated in the northeast and parts of southeast.The more suitable cultivated land is mainly distributed in the southwest towns. The less suitable and unsuitable cultivated land is mainly concentrated in the central and south-southeast regions. High-quality reserve cultivated land resources are mainly distributed in the towns with relatively flat terrain in the east. ③ Through exploring the factors that affect the utilization of cultivated land, the suitable cultivated land conservation measures should be strengthened to ensure the stable yield of high-yield fields.The more suitable cultivated land needs to carry out slope farmland management and improve soil ph. And the less suitable and unsuitable cultivated land should strengthen mine restoration, water and fertilizer conservation and acid regulation. In order to promote the sustainable development of land, the emphasis of reserve cultivated land development should be placed on the towns in the northeast, and the towns in the southeast and southwest should strengthen the protection of ecological environment. These results can provide the basis for the next cultivated land regulation and development in Ningxiang city.

Evaporation-induced salt precipitation in the soil-groundwater system is widespread in arid regions. However, there is no consensus on whether the temporal stage division of evaporation for saline water is consistent with that for pure water, which limits a deeper understanding of evaporation-induced salt precipitation in soil-groundwater system. To clarify the stage division and the controlling factors of evaporation-induced salt precipitation under different NaCl concentrations, indoor soil-column experiments were conducted using quartz sand as the porous medium. Five concentrations were tested: 0, 1, 3, 10, and 50 g/L NaCl. Two parallel replicates were performed for each concentration, giving a total of ten soil columns. The experiment lasted 43 days. Evaporation was recorded, air temperature, surface temperature and profile temperature were monitored, surface salt precipitation was documented, and the mass of the surface salt crust was measured. The results show that: ① The evaporation of pure water is consistent with previous studies and can be divided into three stages: Stage I, constant-rate or high-rate evaporation (days 1-18); Stage II, transitional or falling-rate evaporation (days 18-37); and Stage III, diffusion-limited or low-rate evaporation (days 37-43). ② Evaporation of saline water can also be divided into three stages, but the onset time and intensity of each stage vary with NaCl concentration. With increasing concentration, Stage I becomes shorter and Stage III starts earlier. For 1, 3, 10, and 50 g/L, Stage I lasted 17, 13, 7 and 4 days, respectively, and Stage III started on days 36, 31, 23 and 17, respectively. For moderate to high saline water (≥10 g/L), earlier development of a surface salt crust led to an earlier transition to Stage III and reduced cumulative evaporation. Using the mean cumulative evaporation of the two replicates, the values for 0, 1, 3, 10, and 50 g/L were 228.25, 131.92, 117.45, 109.53, and 29.16 cm, respectively. ③ The controlling factors vary with both concentration and evaporation stage: temperature potential dominated the early-stage evaporation for pure water, freshwater (1 g/L) and mildly saline water (3 g/L); during the transitional stage for moderately saline water (10 g/L), temperature potential and matric potential were both important, while solute potential became stronger and began to contribute to evaporation suppression; for highly saline water (50 g/L), solute potential dominated in the later stage.

The geological storage of CO₂ in deep saline aquifers of sedimentary basins is the main way of CO₂ storage and an important means to achieve carbon reduction goals on a large scale in the short term. The Qingjiang Basin has developed high quality deep saline reservoirs and cap rocks, which have the potential for CO₂ geological storage. However, there has been no systematic study on its storage geological conditions and potential in the past. By the date collection, field investigation, and testing analysis works, a comprehensive study was conducted on the geological conditions of CO₂ storage in the Qingjiang Basin. Embedded analysis was carried out on the characteristics of reservoir-cap conditions, fault development, hydrogeology, geothermal geology, etc. Using the storage potential calculation formula recommended by the Carbon Storage Leaders Forum, the CO₂ geological storage capacity in the Qingjiang Basin was evaluated. The results show that there are two sets of reservoir-cap combinations suitable for CO₂ storage developed in the deep part of the Qingjiang Basin: in Cretaceous, the glutenite of Hekou Formation is the reservoir, and the argillaceous rocks of Tangbian Formation is the cap rock; the glutenite of Lianhe Formation in Cretaceous and the first member of the Xinyu Formation in Paleogene is the reservoir, and the gypsum and argillaceous rocks of the second, third, fourth member of the Xinyu Formation is the cap rock. Well rock character and mineral composition conditions has been developed in the reservoir, with high porosity and permeability; the advantages in the cap rock has been developed with dense lithology, low porosity and permeability, and high breakthrough pressure. The main control fault of the basin has little impact on the strata deformation of the basin after its formation, and the development scale and fault displacement of secondary faults are not significant. The saline aquifers has hydraulic sealing effect and has no hydraulic connection with surface water sources. After preliminary assessment, the effective CO₂ storage capacity of the deep saline reservoir in the Qingjiang Basin is 3.93×10⁸ t, which is of large storage potential, and can be used as a geological disposal space for CO₂ in the Poyang Lake Economic Circle in northern Jiangxi.