To investigate the rare earth element (REE) fractionation patterns, grades, and their influencing factors in different ore blocks of the Bayan Obo REE--Nb--Fe symbiotic deposit, and to provide guidance for research on REE patterns and directional mineral processing at Bayan Obo, elemental mass fraction was conducted using inductively coupled plasma mass spectrometry on samples from different ore blocks of TK13--04 core in the main orebody. Results show that two distinct REE fractionation patterns exist in the main orebody. The REE fractionation pattern of the middle dolomite Fe--REE ores differ from that of the upper and lower dolomite REE ores. The former exhibits an “initial upward inclination followed by rightward inclination” characteristic with increasing from La to Nd and then decreasing from Nd to Lu. In contrast, the latter shows a “rightward inclination” pattern with gradually decreasing from La to Lu. The middle dolomite Fe--REE ores have a lower mass fraction of total REEs compared to the upper and lower dolomite REE ores. The total REE mass fraction is closely related to the degree of light-to-heavy REE (LREE--HREE) fractionation, the REE fractionation pattern, and the total iron (TFe) mass fraction. Higher degrees of LREE --HREE fractionation and higher La/ Nd ratios correlate with higher total REE mass fraction. When the TFe is below 20%, there is no definitive correlation between TFe and the REE mass fraction. However, when the TFe mass fraction exceeds 20%, the total REE mass fraction decreases significantly. Compared to the average proportions of individual light REEs (LREEs) in the mining area, the proportion of Ce in the middle dolomite Fe--REE ore block of TK13--04 is significantly lower ( ~37%), while the proportion of Nd is significantly higher ( ~40. 7%), exceeding the proportion of Ce that is typically the dominant REE in the deposit. The proportion of La in the middle dolomite Fe--REE ore block is also reduced ( ~9%) and the proportions of Pr and Sm are increased. Therefore, the middle dolomite Fe --REE ore blocks hold greater potential for the utilization of Nd, Pr, and Sm elements. For the utilization of La and Ce, development of the upper and lower dolomite REE ore block would likely yield more substantial benefits.

This study is the first to analyze the geothermal resource occurrence conditions and the formationevolution mechanisms in the southern part of Taiyuan City, Shanxi Province, from both geothermal geophysical and geothermal water isotope geochemical perspectives. Based on geophysical exploration data and geothermal water isotope chemical analysis, and combined with regional geological data, a comprehensive study of the geothermal field in southern Taiyuan is conducted. The geophysical methods primarily include gravity, magnetic, and electrical surveys, which are used to analyze the structural characteristics and reservoir distribution of the geothermal field. The geochemical methods mainly include hydrochemical and isotopic analyses, aimed at revealing the origin, evolution, and water-rock interaction processes of thermal groundwater. The geophysical exploration results indicate that the Taiyuan Basin as a whole exhibits a low gravity field and negative magnetic anomalies, reflecting a deeply buried basement and strong tectonic activity, which provide favorable heat sources and reservoir spaces for the formation of geothermal fields. The southern geothermal field of Taiyuan is located at the southeastern margin of the basin, where the gravity field shows a distinct gradient zone, and the magnetic anomalies are characterized by negative values, suggesting the presence of concealed fault structures that serve as channels for deep thermal flow upwelling. Moreover, an apparent arcuate low-resistivity zone exists within the geothermal field, inferred to represent the geothermal reservoir, further demonstrating the favorable conditions for geothermal resource accumulation in this area. Geothermal water isotope geochemical analysis reveals that the thermal groundwater in the southern Taiyuan geothermal field originates from meteoric water, undergoing processes of infiltration, leaching, and transformation into sedimentary (semi-confined) water. During this process, water interacts with surrounding rocks through leaching, dissolution, and cation exchange. Stable components accumulate in the groundwater, while unstable components precipitate, thus forming the hydrogeochemical characteristics of modern geothermal water. The formation of the geothermal field in southern Taiyuan is mainly controlled by the favorable regional geological structure, the development of concealed faults, and the good storage capacity and permeability of the geothermal reservoir.

novel integrated learning-based method for igneous reservoir fluid identification is proposed to address the limitations of traditional approaches in handling complex lithological variations and heterogeneous reservoir spaces, which are crucial for global oil and gas resource development. In this paper, the Adaptive Multi-- Objective Swarm Crossover Optimization (AMSCO) innovatively combined with an engineered extreme gradient boosting (XGBoost) based on deep forest method for fluid identification in complex lithologic igneous reservoirs using conventional logging data sets. Methodologically, firstly, the AMSCO algorithm is used to optimize the imbalanced conventional logging data set, effectively solving the problem of class imbalance in the data set, providing a more balanced data basis for subsequent model training. Secondly, a cross-adaptive XGBoost and deep forest (CXDF) is constructed by fully utilizing XGBoost􀆳s advantages in processing large-scale and high-dimensional data, as well as the excellent performance of deep forest in feature extraction and classification tasks. Thus, the
accurate identification of reservoir fluids in complex lithologic igneous rocks is achieved. Then, to verify the effectiveness of this method, the model was applied to the simulated well together with support vector machine (SVM), XGBoost and XGBoost-based deep forest for comparison. Finally, the model is applied to the actual stratum. The results show that the evaluation index of the proposed method in the simulated well is superior to other methods, especially in the identification of non-water-producing reservoir fluids. In the application to actual formations, this method maintains high identification performance in different reservoirs with different fluid structures, and shows good generalization ability and stability.

Multiple wells in the carbonate gas reservoirs of the Lower Permian Qixia Formation in the central Sichuan region of the Sichuan Basin have encountered industrial gas flows, but the anisotropy of the single well reservoir is strong and the physical parameters are obviously different, so it is difficult to guide the well location deployment of this type of gas reservoir by conventional geophysical means. Therefore, clarifying the main controlling factors of the Qixia Formation gas reservoir, accurately predicting the distribution of thin dolomite reservoirs, and further improving the development efficiency of the gas reservoir are the key and difficult points of geophysical work. This article combines core, logging, seismic and other data to first determine the main controlling factors for the enrichment and high yield of the Qixia Formation gas reservoir in the study area, and summarizes the rock physical characteristics and seismic response patterns of the dolomite reservoir. Innovation has formed key technical processes for thin reservoir prediction, such as high-resolution processing technology, qualitative reservoir prediction based on wavelet reconstruction, fine characterization of ancient landforms constrained by layers, inversion technology constrained by reconstruction curves, and fracture and cave prediction technology constrained by porosity curves. This has improved the ability to vertically resolve thin reservoirs of 1--8 m in the research area, and ultimately characterized a favorable area for the development of dolomite reservoirs as 75 km2. The research results indicate that: ① There is an obvious positive correlation between the thickness of fracture-vuggy dolomite thin reservoir, fracture-cave development degree and productivity in the Qixia Formation gas reservoir in the study area. ② Before the sedimentation of the Qixia Formation (paleogeomorphology), reservoirs were developed in the lower part, and the reservoir properties in the slope area during the karst period were better. ③ The reservoirs of Qixia Formation in the study area are mainly developed in the middle and upper parts, and the seismic profile shows the reflection characteristics of “weak peaks” in the middle and upper parts, and the more the reservoirs are developed, the more obvious the response characteristics of “weak peaks” are. This article combines seismic facies, paleogeomorphology, reservoir thickness, and fracture distribution parameters for the first time to establish a series of key technologies for predicting dolomite reservoirs suitable for the study area, achieving effective prediction of the spatial distribution of thin reservoirs in the Qixia Formation and laying the foundation for increasing reserves and production in oil fields.

Abstract: Geochemical characteristics and potential evaluation of source rocks is a core component of thepetroleum system and plays a crucial guiding role in the exploration and development of hydrocarbon resources. To systematically assess the hydrocarbon generation potential of source rocks in the Shahezi Formation within the LishuFault Depression of the Songliao Basin and to clarify their geochemical characteristics and distribution patterns, the authors utilized core observations and well log interpretations to identify the macro sedimentary facies and vertical distribution of organic-rich mudstone intervals. A series of geochemical analyses (total organic carbon content meas-urement, rock pyrolysis, kerogen carbon isotope analysis, reflectance in oil testing, and gas chromatography-mass spectrometry of saturated hydrocarbon biomarkers) were employed to quantitatively characterize key parameters of the source rocks. The research results indicate that the lower part of the Sha1 Member and the middle part of the Sha2 Member of the Shahezi Formation are developed with mudstone deposits belonging to coastal-shallow lacustrine and semi-deep to deep lacustrine subfacies, which constitute the main source rock intervals of the Lishu Fault Depression. The depositional environment is characterized by weak redox conditions, and the migration of the depositional center controls the distribution of high-quality source rocks. In terms of organic geochemical character-istics, the source rocks of the Shahezi Formation exhibit high organic matter abundance, with TOC values ranging mainly from 1. 0% to 6. 8% and an average of 2. 5% . The vast majority of samples exceed the quality source rock threshold (w(TOC)≥ 2. 0% ). The kerogen is predominantly Type Ⅲ, followed by Type Ⅱ2, with a few samples exhibiting characteristics of TypeⅡ1 and TypeⅠ. Thermal maturity assessment indicates that the source rocks have reached the mature to over-mature gas generation stage (Ro > 1. 3% , average Tmax = 455. 1 ℃). Comprehensive evaluation indicates that the Shahezi Formation in the Lishu Fault Depression of the Songliao Basin is characterized by the rich main source rock development, high organic matter abundance dominated by gas-prone types, high thermal maturity having entered the gas generation stage, and distinct spatial differentiation, demonstrating excellent hydrocarbon generation potential. 

Abstract: Outang landslide is a typical giant creeping landslide in Three Gorges Reservoir area, with a volume of up to 90 million m3. To date, its maximum surface horizontal displacement has reached nearly 1 600 mm, and the maximum deep displacement exceeds 500 mm. The surface deformation exhibits extensiveness, persistence, and accelerating rate, whereas the deep deformation is marked by bedding movement, multi-layered activity, and sustained creep. The mechanism of deep reactivation-deformation and long-term stability of landslide are hot topics in the field of geological hazard research. Regarding Outang landslide, key issues such as it exhibits deep-seated integral sliding, the evolutionary mechanisms of reactivation-deformation, major potential risk sources, and effective
mitigation strategies were investigated. Based on 14 years of high-resolution monitoring data and multi-source exploration
results, the authors conducted comprehensive research integrating geological conditions, landslide characteristics, and reactivation-deformation models. This included long-term continuous geological tracking, retrospective analysis of deformation stages, and correlation studies between deformation rates and rainfall. The findings confirm the existence of deep-seated integral sliding in Outang landslide. Its integral deformation pattern follows a chain-reaction mechanism characterized by “Tier--3 sliding body pushing Tier--2 sliding body, which in turn drives Tier--1 sliding body. ” The intrinsic triggers of reactivation-deformation mechanism originate from underlying multi-layered weak intercalated structure prone to sliding. Factors such as high-frequency heavy rainfall, intense reservoir water inundation effects, and insufficient stability of Tier--3 sliding body have collectively exerted significant influence on integral reactivation-deformation of landslide. Among these, heavy rainfall has emerged as the dominant driving force of persistent deformation. Under heavy rainfall conditions, the progressive deformation characteristics are as follows: Tier--1 sliding body deformation rate (0. 3 mm/ d) < Tier--2 sliding body deformation rate (1. 0--3. 2 mm/ d) < Tier--3 sliding body deformation rate (1. 6--6. 0 mm/ d). Based on these observations, the criterion of identifying severe deterioration trends in deep slip zone soil of creeping landslides is established as: a sustained surface displacement rate exceeding 1. 0 mm/ d for more than 90 consecutive days, with significantly higher rates during flood seasons or rainy periods. The key to risk control lies in enhanced monitoring and numerical early warning for Tier--3 sliding body and the toe uplift zone.

Abstract: In order to study the effects of dry density and matric suction on the shear strength characteristics of unsaturated volcanic soils, this paper takes volcanic soils in Antu County, Jilin Province as the research object, and prepares soil samples with three dry densities and six water content levels. The soil-water characteristic curvesof volcanic soils with different densities were determined by the pressure plate instrument method, and the soil-water characteristic curves were fitted using the Van Genuchten model. Direct shear test was used to obtain theshear strength indexes of the samples under different water content conditions. The results indicated that the SWCC of volcanic soils were influenced by dry density, and the matric suction of volcanic soil increased with the rising of dry density under the same volumetric water content condition. The dry density of the soil has a good relationship with the VG model parameters (the reciprocal of intake value a, parameters n and m, and residual water content θr). Both the internal friction angle φ and cohesion c increased with dry density, while they increased initially and decreased with matric suction. The shear strength of volcanic soils is affected by the combination of dry density and matric suction. An rising in dry density not only enhances the occlusion between particles, but also reduces the internal pores of the soil and increases matric suction, which leads to an rising in the shear strength of volcanic soils. This study established the relationships between the internal friction angle φ, cohesion c, dry density and matric suction in volcanic soils, providing a reference for selecting strength parameters in geotechnical engineering projects in volcanic soil regions.

To investigate the conductivity mechanism and fluid distribution characteristics of tight sandstone reservoirs in the Ordos Basin and to construct an accurate saturation model, this study conducted a series of petrophysical experiments, including porosity-permeability tests, resistivity measurements using the centrifuge method,and NMR (nuclear magnetic resonance) response analysis, on 11 rock samples from the study area. Nitrogen gas was used in the porosity-permeability experiments, revealing porosity values ranging from 5. 21% to 11. 26%, and permeability values ranging from (0. 132 8--1. 261 1) ×10 -3 μm2. The resistivity tests under varying centrifugation durations provided key electrical parameters: the cementation exponent m (ranging from 2. 053 to 3. 293) and the saturation exponent n (ranging from 0. 714 to 2. 131). The NMR technique, which leverages the relaxation time of hydrogen nuclei within the rock, was used to characterize reservoir pore structures and fluid mobility. The T2 spectrum obtained through NMR enabled the distinction of pore sizes and their proportions. Results indicated that the tight sandstones in the study area exhibit similar properties and pore structures. The T2 spectrum showed a wide distribution (0. 1--1 000. 0 ms), typically presenting a bimodal pattern with a boundary at 10 ms. Based on empirical methods, mercury intrusion data, and NMR T2 spectrum characteristics, the T2 range for small pores was defined as 0. 01--5 ms, and for large pores as 5--10 000 ms. The findings show that fluid mobility is significantly
higher in large pores than in small ones, and water content in small pores increases during centrifugation. After converting T2 values into corresponding pore diameters, it was found that movable water is mainly distributed in the 1--10 μm range, followed by 0. 01--0. 1 μm and 0. 1--1 μm ranges. Using the fractal dimension method, a positive correlation was established between fluid distribution and electrical conductivity: greater fluid presence in large pores corresponds to smaller fractal dimensions and higher conductivity.

Abstract: Tiejiashan granite in the Anshan area, Liaoning Province, represents the oldest known K-rich granite
in the North China Craton. This study integrates petrography, zircon U--Pb geochronology, whole-rock geochemistry,
Lu --Hf isotopic and deformation structural analysis to elucidate the petrogenesis, tectonic setting, and dynamic mech-
anism of Mesoarchean K-rich granite. Zircon U--Pb geochronological data indicate that the Tiejiashan K-rich granite
formed during the Mesoarchean (3. 0--2. 9 Ga). The samples exhibit high w(SiO2)(68. 03%--71. 24% ), w(Fe2O3
T)(3. 31% --4. 90% ), w ( K2O + Na2O) (7. 73% --7. 99% ), and high Ga/ Al ratio, coupled with low w ( MgO)
(0. 53%--0. 80% ). Rare earth elements exhibit distinct negative Eu anomalies (δEu = 0. 21--0. 31). The rocks are
obviously enriched in large ion lithophile elements (LILE, e. g. Rb, Th, U, and K), while depleted in high field
strength elements (HFSE, e. g. Nb, Ta, P, and Ti). Additionally, they display high zircon saturation temperatures
ranging from 822 ℃ to 926 ℃. Based on these geochemical characteristics, the Tiejiashan granite is classified as an
A-type granite. No Mesoarchean mafic rocks have been identified in the Anshan area. Petrographic and geochemical
analyses reveal that the Tiejiashan granite demonstrates metaluminous to peraluminous affinities. The Tiejiashan
granite has low εHf (t) values ( - 8. 23 to - 14. 75), with TDM2 model ages between 4. 0 and 3. 7 Ga, suggesting
derivation from the partial melting of ancient crustal material. Variations in components such as TiO2, CaO, MgO,
P2O5, Sr, and Zr show linear correlations with w (SiO2) content on Harker diagrams, indicating experienced continuous
magmatic evolution and differentiation. Combining the geochemical data and tectonic deformation characteristics, it is
inferred that lithospheric mantle underplating induced regional extension in the Anshan area during the Mesoarchean.
Heat from the lithospheric mantle likely triggered partial melting of the lower crust and facilitated rapid diapiric
ascent of magma, lead to the formation of Tiejiashan granite.

Abstract: In recent years, moderate to strong earthquakes have frequently occurred in the Songliao Basin. To investigate the seismicity in the region, the authors calculate the minimum completeness magnitude (Mc) of the Songliao Basin based on the earthquake catalog from the Jilin Earthquake Agency (2009--2024) by using the maxi-mum curvature method and apply the Gutenberg--Richter law to fit the corresponding b-value. The results show that the Mc for the Songliao Basin is 1. 4, indicating either a strong monitoring capability of the local network or a higher density of small earthquakes. However, industrial noise in some areas may result in under-detection of low-magni-tude events. The fitted b-value for the Songliao Basin is 0. 59, lower than the b-value for the entire Northeast China
region (0. 74), suggesting that moderate to strong earthquakes will be likely to occur in the Songliao Basin region in the future. Further analysis of the relationship between the earthquake distribution and the geological structure of the underlying basin in the Songliao Basin is conducted, and statistical analysis is employed to explore the correspondence between earthquake distribution and hypocentral depth. The results show that the vertical distribution of the earthquakes is closely related to the key deep geological interfaces within the basin. Earthquakes mainly occurred from 5 km to 10 km. The International Continental Scientific Drilling Program (ICDP) borehole SK--2 in the Songliao Basin revealed that at the depth of 6 km, a regional unconformity interface of the seismic reflector named T5 separates the Cretaceous sedimentary cover from the underlying Triassic basement, and at the depth of
7 km, a basement detachment fault occurs within the dual-layer Triassic--Paleozoic basement system.

This study investigates members 2--3 of the Late Cretaceous Qingshankou Formation in the Gulong area of the Songliao Basin. By integrating core data, well-logging information, magnetic susceptibility and chromaticity measurements, wavelet transform analysis of logging curves, and cluster analysis, the coupling mechanism between high-frequency climatic oscillations and sequence development in continental lacustrine basins was systematically revealed. The principal findings are summarized as follows: ① Two depositional environments lacustrine and deltaic facies were identified in the studied interval, which were further subdivided into six microfacies: deep-lake mud, semi-deep lake mud, shell sand, turbidite, prodelta mud, and sheet sand. A delta-lacustrine sedimentary evolution model was established to characterize their vertical stacking patterns. ②Two complete third-order sequences were recognized based on lithologic associations, well-logging responses, and wavelet transform time-frequency analysis. These sequences were divided into four system tracts, lowstand (LST), transgressive (TST), highstand (HST), and regressive (RST). Sequence boundaries were characterized by GR curve inflection points, lithologic abrupt changes, and energy cluster transitions in time-frequency spectrograms. ③Paleoclimate
evolution was quantitatively reconstructed using magnetic susceptibility and chromaticity indices through SPSS cluster analysis. The results revealed a climatic cyclicity of “cooling-warming-cooling-warming-cooling” with an anomalously
warm-humid phase during 86. 895--86. 364 Ma closely linked to lacustrine anoxic events (LAEs). This phase was attributed to enhanced hydrological cycling-triggered terrestrial coarse clastic input and intensified reducing conditions. Overall, paleoclimate governed sequence differentiation by regulating hydrological cycling and sediment supply. During warm-humid phases, strengthened water circulation promoted fine-grained mudstone deposition, forming TST and HST system tracts, whereas under relatively dry-cold conditions, weakened water circulation favored coarse-grained gravity flow sedimentation, developing RST and LST system tracts. 

Abstract: The Huoshiling Formation in the Longfengshan gas field, southern Songliao Basin, has achieved
cumulative proved gas reserves exceeding 10 billion cubic meters, demonstrating favorable reservoir properties and
exploration potential in deep volcaniclastic rock sequences. Clarifying the characteristics and controlling factors of
high-quality volcaniclastic reservoirs aids in expanding favorable zones for deep-buried gas reservoir exploration and
facilitating the deployment of development wells. Based on the drill core description, blue-dyed epoxy-resin impreg-
nated thin section observation, scanning electron microscopy analysis, the porosity-permeability measurements and
high-pressure mercury injection tests, a systematic study was conducted to characterize the lithology, lithofacies,
and reservoir development patterns of volcaniclastic rocks, in order to clarify the controlling factors and spatial
distribution of high-quality reservoirs. The results reveal that: the Huoshiling Formation in the Longfengshan gas
field is composed of thirteen lithological types in four categories of volcaniclastic rocks, formed in both subaerial
and subaqueous environments, and dominated by volcaniclastic deposits of explosive facies. Four distinct pore types
were identified, the intergranular pores, intragranular pores, intracrystalline pores, and microfractures.
The intergranular and intragranular porosity constitute the predominant reservoir space, especially for the volcanic breccia
which exhibits the highest porosity, 37% and 53% of intergranular and intragranular pores, respectively. The
porosity of volcaniclastic reservoirs ranges from 1. 6% to 13. 8% , and the permeability ranges from 0. 002 ×10 - 3 μm2
to 0. 751 × 10 - 3 μm2. They are classified as medium-porosity / low-permeability reservoirs, developing micron-scale
and nano-scale pore throats, the maximum throat ranges from 0. 020 μm to 2. 830 μm. Eogenetic chlorite cementa-
tion and albitization coating of the particles effectively inhibited compactional porosity loss, thereby preserving inter-
granular pores; Devitrification of volcanic glass/ ash matrix in shallow burial stage, and the organic acid dissolution
in deep burial diagenesis significantly enhances secondary porosity development, composing a key factor that controls
the development of high-quality volcaniclastic reservoirs. Three subfacies exhibit the highest proportions of high-quality
reservoirs (porosity > 6%), including diatreme subfacies of volcanic conduit facies, subaqueous volcaniclastic flow
deposits and fallout subfacies of explosive facies, which can be regarded as priority targets for deep gas exploration.

To deeply reveal the paleoclimate characteristics of the Sifangtai Formation in the Songliao Basin, infer the controlling factors of climate change, and improve the information implied by climatic evolution, magnetic susceptibility and chromaticity tests were conducted on the core (140. 0--380. 5 m) from the ZKQA1--1 in the Qian an area. Through Pearson correlation analysis, it was found that magnetic susceptibility and chromaticity data were weakly correlated with stratigraphic depth. Brightness (L∗) was negatively correlated with redness (a∗) and yellowness (b∗), while redness (a∗ ) was positively correlated with yellowness (b∗ ), indicating that the data were minimally affected byagenesis and had reliable paleoclimate significance. Through SPSS cluster analysis, high-frequency magnetic susceptibility, low-frequency magnetic susceptibility, frequency-dependent magnetic susceptibility, brightness (L∗), redness (a∗), and yellowness (b∗) were filtered once, and four filtered mean values were obtained for each dataset. The filtered values were classified into four climatic types (cold-dry, relatively cold-dry, relatively warm-wet, and warm-wet) based on paleoclimate proxy indicators. To avoid errors caused by
semi-quantitative analysis of climatic types using magnetic susceptibility and chromaticity data, the six datasets representing climatic types were assigned numerical values (cold-dry: 0. 5, relatively cold-dry: 1. 5, relatively warm-wet: 2.5, warm-wet: 3.5), averages were calculated based on depth summation, and comprehensive temporalscale analysis was performed in combination with lithological and well-log data. The results showed that the magnetic susceptibility and chromaticity data of the Sifangtai Formation core from the Well ZKQA1--1 indicated a relatively cold-dry climate during the mid-Campanian (76. 08--75. 65 Ma), and the paleotemperature decrease in this stage was associated with the migration of the Intertropical Convergence Zone (ITCZ). A relatively warm-wet to warmwet climate was identified during the mid-late Campanian (75. 65--74. 32 Ma), with an extreme paleotemperature peak observed at 75.55 Ma, while the slight paleotemperature decline from 75.55 to 74.32 Ma was linked to the Campanian--Maastrichtian Boundary Event (CMBE). During the late Campanian (74. 32--73. 19 Ma), a cold-dry to relatively cold-dry climate was recorded, with an extreme paleotemperature minimum at 74. 13 Ma, followed by a relatively warm-wet climate from 73. 19 to 72. 86 Ma, and the paleotemperature rise from 74. 13 to 72. 86 Ma might be related to intermittent volcanic activity prior to the late Campanian Deccan Traps eruption event. Overall, the
paleoclimate of the Sifangtai Formation was demonstrated to correspond well with global climate trends, representing a relatively warm and dry climatic type.

When using machine learning techniques to identify lithology based on the feature vectors of each sample in the logging dataset, it is generally imperative to first clean and preprocess the dataset to detect missing data and outliers in it. Affected by the distortion of logging curves or the disparities in the quantity of curves between wells, the logging dataset used for lithology identification is usually incomplete, with a large amount of missing data and outliers. This renders it challenging for the majority of machine learning methods to be directly applied. To tackle this problem, a K--Nearest Neighbors algorithm based on the Partial Distance Strategy (PDSKNN) is proposed. This algorithm improves the traditional K--Nearest Neighbors algorithm (KNN) based on a method (PDS) that capable of computing the distance between feature vectors containing missing values, enabling the direct application to incomplete dataset. The PDSKNN algorithm was experimentally implemented and tested in the lithology identification task of complex igneous rock reservoirs in a certain region. When the data missing rate was 2. 7%, the lithology identification accuracy of the PDSKNN algorithm was as high as 91. 90%. This result indicates that the PDSKNN algorithm effectively solves the problem of incomplete dataset at the algorithm level. For the purpose of further validating the effectiveness of the PDSKNN algorithm, certain data in the dataset was randomly deleted to elevate the missing rate, and the changes in the identification accuracy were observed. The experimental results reveal that as the missing rate increases, the identification accuracy gradually decreases. However, even when the missing rate attains 20%, the identification accuracy of the PDSKNN algorithm still remains above 80%. This result proves that the PDSKNN algorithm can maintain a relatively high identification accuracy in the case of severe data missing. Finally, by simulating the missing conditions of curves in different wells, a comparative analysis of the changes in the identification effect of the PDSKNN algorithm was carried out. As the number of missing curves increases, the lithology identification performance in the wells decreases to some extent, but the identification effect of most well sections is still guaranteed. It shows that the PDSKNN algorithm has strong robustness to the missing curves in the wells.

The exploration focus of the Junggar Basin has gradually shifted from the hydrocarbon generation center of the sag to the peripheral uplift area, and it is particularly important to understand the distribution characteristics of oil and gas reservoirs in the Dabasong Uplift, the authors have conducted research on the main controlling factors and development mode of high-quality reservoirs in the Dabasong Uplift by means of core observation, thin section identification, well logging interpretation and various experimental analyses. It is believed that the Dabasong Uplift was in the underwater reducing environment during the eruption period, and the carboniferous igneous rocks were mainly basic rocks, including diabase of volcanic channel facies, crystalline tuff of the underwater sedimentary subfacies, breccia clastic tuffs of the underwater volcaniclastic flow subfacies, basalt and andesite of underwater overflow facies, and sedimentary tuffs of the volcanic sedimentary facies. Among them, breccia clastic tuffs of the underwater volcaniclastic flow subfacies and the diabase of volcanic channel facies are the dominant lithologic lithofacies in the study area. The breccia clastic tuffs has more concentrated pore throat distribution, good connectivity and greater contribution of pore throat, while the diabase has more dispersed pore throat distribution and good connectivity. The reservoir space of igneous rocks in the study area is dominated by intrachrystalline solution pores, matrix solution pores, structural fractures and solution fractures. The porosity of carboniferous igneous rocks is less than 5% (51. 9%), between 5% and 12% (29. 6%), more than 12% (18. 5%), the permeability is less than 1 ×10 -3μm2 (81. 5%), between (1 and 5) ×10 -3μm2 (16. 6%), and more than 5 ×10 -3μm2 (1. 9%), the whole belongs to the medium and low porosity-low permeability reservoir. The formation of effective reservoirs is controlled by lithologic lithofacies, dissolution and fractures, and is a weathering and dissolution modified reservoir based on lithologic lithofacies and dominated by fractures. It is a favorable zone for oil and gas exploration in areas with dominant lithological lithofacies, weathering and dissolution, active fluid dissolution and fracture development.

Abstract: Aming to the unique temperate forest vegetation within the Northeast Tiger and Leopard National
Park, a study on multi-source remote sensing image coverage classification has been conducted, which aims to
utilize modern remote sensing techniques and advanced machine learning methods to perform fine classification of
complex vegetation types, thereby better understanding the ecological conditions of the region and providing scientific
basis for the conservation efforts in the Northeast Tiger and Leopard National Park. Firstly, the authors employed
multi-scale image segmentation technology to decompose the original remote sensing images into a series of small
regions with similar texture and color features, which helps reduce data redundancy and highlight different characteristics
of vegetation. Subsequently, these segmented images has been optimized by extracting feature parameters that effec-
tively distinguish different types of vegetation. Then, the authors input these optimized feature parameters into three
different machine learning classifiers for training and testing, including support vector machine (SVM), C5. 0 deci-
sion tree and random forest. The experimental results show that, in terms of classification accuracy, random forest
achieving the highest accuracy of 91. 33% , and C5. 0 decision tree reaching 89. 59% , with the Kappa coefficients
of 0. 90 and 0. 88, respectively. In comparison, the classification accuracy of support vector machine was lower, at
only 58. 96% , and the Kappa coefficient is 0. 54. These results indicate that, for distinguishing vegetation cover
types and identifying other land features, the random forest algorithm has significant advantages. It not only accu-
rately distinguishes different vegetation types in complex backgrounds, but also effectively identifies other features
such as roads and buildings.

In order to explore the electromagnetic wave detection response characteristics of shallow under-
ground buried targets in a specific medium and meet the urgent needs of urban underground pipeline management
and unknown target detection, a high-performance antenna for ground penetrating radar system was innovatively
designed based on the in-depth analysis of the rectangular waveguide theory. Firstly, according to the propagation
characteristics of electromagnetic waves in the rectangular waveguide, the basic model of the antenna is constructed,
the cut-off frequency of the antenna is calculated, and the monopole probe is selected as the effective excitation
source. Secondly, the high frequency structure simulator (HFSS) of Ansys electronics desktop (AEDT) simulation
platform was used to carry out numerical simulation and optimization of the antenna model. By in-depth analysis of
the influence of the installation position and insertion depth of the monopole probe in the rectangular waveguide on
the transmission characteristics of the antenna, the S11 reflection coefficient, voltage standing wave ratio (VSWR) and
radiation pattern of the antenna were accurately adjusted. Finally, in order to verify the accuracy of the theoretical
analysis and simulation results, the antenna was fabricated with aluminum foil board material, and the ground
penetrating radar system was built with vector network analyzer (VNA) in a controlled sand trough environment for
field testing, and the detection height of the antenna was adjusted to cover underground targets at different depths.
Experimental results show that the antenna can stably and accurately identify all preset targets. The ground penetrating
radar antenna based on rectangular waveguide shows excellent directionality, ultra-wideband and high resolution
after finely adjusting the insertion depth of the probe and the distance between the probe and the short-circuit
surface of the rectangular waveguide to achieve the best matching of antenna impedance, which provides an efficient
and accurate new tool for urban underground space management and unknown target detection.

     In order to study the importance of the spatial and temporal distribution characteristics of sea ice in
the marine disaster warning, resource development and global climate change research, the authors use multi-tem-
poral remote sensing data to extract and analyze the spatial distribution range and sea ice thickness information in
Liaodong Bay of Bohai Sea during winter months based on the remote sensing inversion modeling of sea ice thick-
ness. First, the sensitive wavebands that have a significant response to differences in sea ice thickness were
screened based on the variance analysis method, and a sea ice thickness-sensitive band reflectance statistical corre-
lation model was constructed based on the regression analysis method. The multi-temporal remote sensing data were
used further to reflect the sea ice thickness in Bohai Sea and to analyze the spatial and temporal distribution charac-
teristics of sea ice. Experimental results show that the red-light band data of Landsat satellites have high sensitivity
in retrieving sea ice thickness, and the regression statistical model established on the red-light data has a linear fit-
ting regression sum of squares as high as 0. 975 1, which indicates that the model has high accuracy and reliability.
The result of Landsat red-light band data used for retrieval on the sea ice thickness and spatiotemporal distribution
of sea ice in Liaodong Bay of Bohai Sea indicates that the sea ice begins in late December every year at Panjin and
Yingkou in Bohai Sea, and reaches the thickest and largest distribution area by January. As the temperature
gradually rises, sea ice gradually recedes in early February, and completely disappears by early March. In addi-
tion, the proportion of thin ice is generally high in each winter month, while that of thick ice is relatively low. The
sea ice in Bohai Sea freezes earlier and thicker in higher latitude areas or closer to the coast, and retreats later. On
the contrary, the ice in the low latitude areas freezes later and retreats earlier.

    Electrical resistivity tomography (ERT) method is a geophysical exploration technique based on
the differences in resistivity of media. Due to its characteristics of non-destructive and high efficiency, it is widely
used for detecting and evaluating subsurface anomalies. The authors take a gold mine goaf as the subject, numerical
simulations for analyzing potential anomalous characteristics in goaf areas, and field investigations to verify the
applicability of ERT in detecting goaf collapse zones, which providing a scientific basis for goaf management.
Focusing on Wenner, dipole-dipole, Wenner--Schlumberger, and pole-pole electrode arrays, RES2DMOD forward
modeling software was used to construct models of a single isolated low-resistivity anomaly and a semi-high and
semi-low resistivity anomaly to simulate fully water-filled and partially water-filled conditions of goafs. The data were
processed by using RES2DINV inversion software with the least-squares method for inversion calculations. The results
show that the dipole-dipole array exhibited the best performance for the fully water-filled anomaly, which accurately
locate and describe the geometric shape and resistivity characteristics of low-resistivity anomalies with high resolution.
For the partially water-filled semi-high resistivity and semi-low resistivity anomaly, the inversion accuracy of all arrays
decreased, but the dipole-dipole array still outperformed the others, effectively reflected the distribution
characteristics of the anomalies. In field investigations, the dipole-dipole array was employed for data acquisition.
The processed data revealed a low-resistivity zone at the position approximately 115 m (30 m in depth) in the study
area. Based on geological and hydrogeological conditions, the low-resistivity zone was inferred to be a goaf collapse
zone. The findings indicate that the dipole-dipole array effectively reflects the extent and characteristics of goaf collapse
zones, providing valuable insights for estimating the approximate range and developmental depth of anomalous areas.

    In order to improve the accuracy of extracting erosion gully information based on remote sensing data, the erosion gully extraction model based on multi-source data fusion and object-based image analysis (OBIA) is proposed to extract the distribution information of erosion gully in Dehui City, Jilin Province, with a view to play an early warning role for the generation of erosion gully. The study fuses Sentinel --1 radar data, Sentinel-2 optical remote sensing images, and topographic data of the study area, and uses the multiresolution segmentation method to segment the features in the study area. Based on the results of multiresolution segmentation, intensity, texture, spectral, index, topographic and geometric features are extracted for constructing multi-dimensional sets, and the contribution of features is evaluated and optimized using the random forest Gini index to obtain the optimal set of features. The random forest extraction model based on OBIA was constructed to extract erosion gully information in the study area, and the extraction accuracy was evaluated using the method of generating random points and visually deciphering them. To further investigate the effect of multi-source data fusion on the accuracy of erosion gully extraction, based on the same sample dataset, the erosion gully in the study area was extracted for different data sources and its accuracy was compared. The results show that the overall accuracy of erosion gully extraction based on multi-source data fusion is 94. 03% , and the Kappa coefficient is 0. 839, indicating that the model has a good performance. Compared with a single data source, multi-source data fusion has higher extraction accuracy, and provides a large number of effective feature values for the random forest model. Erosion gullies in Dehui City are mainly distributed in the central and southwestern part of the city, and the erosion as a whole shows a northeast-southwest belt direction, mostly distributed around the settlement and connected with certain water systems, and its erosion situation needs to be emphasized.

Abstract: As a complex rock mechanics medium, the plastic deformation of soft rock brings rock mechanics problems to hydropower engineering in the large and medium-sized hydropower projects, the creep behavior in water has a great influence on the stability of rock mass. In order to probe into the creep law of soft rock under water-bearing condition, the authors take argillaceous siltstone under different water-bearing states in a power station area in Haozhou as the research object. The effect of moisture content on the creep rate and creep stage of argillaceous siltstone is analyzed through tri-axial compression creep tests under three different water content states: dry, natural and saturated. According to the characteristics of steady-state creep and accelerated creep test curves of rock, the Nishihara creep model is used to construct the optimal creep model of argillaceous siltstone considering the effect of moisture content based on the accelerated creep test curve's characteristics. The result shows that the existence of water affects the creep deformation of argillaceous siltstone. With the increase of water content, the instantaneous strain and creep strain of rock show a continuous increasing trend. Under the same stress level, the higher the water content is, the lower the long-term strength of argillaceous siltstone is, and the longer it takes to enter the steady-state creep stage, the larger the creep deformation is. When the axial stress does not reach the long-term strength of the siltstone, the argillaceous siltstone of the rock will produce transient strain at first and then be in the steady-state creep stage. As the axial stress exceeds the long-term strength of the siltstone, the accelerated creep stage occurs in the rock. When the nonlinear viscoplastic element is introduced, and the traditional Nishihara creep model is connected with it in series, the nonlinear viscoelastic-plastic optimized creep model can describe the accelerated creep stage of soft rock more accurately, and have better applicability.

Abstract：To study imaging optimizing algorithms for low signal-noise rate (SNR) seismic data in rugged topography,an effective coherence constraint noise suppression method is established according to the obvious difference in coherence characteristics between noise and effective reflected signals, which can provide theoretical and technical support for practical applications of the imaging in rugged topography. In order to solve the problem of conventional imaging of low signal-to-noise ratio seismic data in rugged topography, a coherence constraint Gaussian beam migration method for rugged topography is proposed in this paper. The elevational correction of time-shift eliminates the inaccuracy of beam decomposition caused by rugged topography. Horizontal projection equivalent discrete interval(HPEDI) for beam center and receiver location is designed to solve the drawback of unbalance of imaging amplitude. About the coherence constraint, a new stable complex domain weighted coherence spectrum computing method is proposed, and the threshold extraction and exponential strengthening methods for effective reflection signal are designed to achieve the effective suppression of random noise and incoherent false imaging.  Numerical experiments of 2 synthetic data examples and 2 measured data examples are applied to validate the effectiveness of the proposed methods in noise and false image suppression. The proposed HPEDI method can achieve significant image optimization in amplitude equalization and arc false image suppression for the synthesized data in rugged topography. The coherence spectrum of real measured data verifies that the weighted coherence spectrum is smoother and more stable than the conventional coherence spectrum. Most of the arc false images of the synthesized data in a layered model are suppressed by using the threshold of coherence spectrum. The rugged real measured low signal-to-noise ratio data prove that the proposed coherence constraint method suppresses random noise obviously. The proposed coherence constraint migration imaging method can effectively suppress the noise and false imaging without coherence characteristics in the imaging process, and can significantly improve the imaging effect.

Abstract：The Chaganhua Subsag, one of the subsags in the Changling Fault Depression, Songliao Basin, is divided into two parts: the northern and the southern. The spatial relationships between the source rocks and reservoir rocks and the interstitial physical properties of the volcanic rock hydrocarbon reservoirs are similar in the northern and southern parts. However, exploration and development reveal that the distribution and activity periods of the faults in the southern and northern parts of the subsag are different, and volcanic rock hydrocarbon reservoirs in the northern part of the subsag are more than those in the southern part. In this study, seismic interpretation data were used to statistically analyze the occurrence and activity period of the main active faults in the Chaganhua Subsag, 2D hydrocarbon accumulation simulations were processed with key well-crossing profiles on the basis of the source rock burial history. The matching relationships between the activity periods of the main active faults and the hydrocarbon charging periods in the southern and northern parts of the Chaganhua Subsag were compared. The controlling effects of fault activity on hydrocarbon migration and accumulation, and the causes of the differences in the distributions of volcanic rock reservoirs in the northern and southern parts of the subsag were analyzed. The results revealed two hydrocarbon charging periods of volcanic reservoir in the Chaganhua Subsag. One period was the Early Cretaceous Denglouku stage, and the other was from the end of the Early Cretaceous Quantou stage to the Late Cretaceous Qingshankou stage. Three levels of faults were developed in the Mesozoic strata under an extensional structural environment. The secondary faults were the important factors in hydrocarbon migration and accumulation. Many secondary faults developed with long activity period in the northern part of the Chaganhua Subsag. Their activity period was as long as from the Early Cretaceous Huoshiling stage to the end of the Quantou stage or even to the end of the Late Cretaceous Qingshankou stage. The hydrocarbon charging period as well matched the fault activity period. The secondary faults in the northern part of the subsag performed the main migration paths, in the volcanic hydrocarbon accumulations under the coordinating of unconformities. In the southern part of the subsag, the secondary faults were less developed with short activity periods from the Early Cretaceous Shahezi stage to the Denglouku stage. These faults were bad for matching the hydrocarbon charging periods, and had little control effects on hydrocarbon accumulation in the southern part of the subsag, and played a limited role in hydrocarbon migration. Some of these faults with long activity periods could be beneficial for hydrocarbon migration with the assistance of advantageous volcanic facies belts. The fault activity periods and their matching relationships to hydrocarbon charging periods are the main reasons for the differences in volcanic rock hydrocarbon reservoirs between the southern and northern parts of the Chaganhua Subsag.

Abstract：The timing of the final closure of the Paleo-Asian Ocean is one of the controversial issues in the field of geoscience. The central Jilin Province, which was controlled by the evolution of the Paleo-Asian tectonic regime during the Paleozoic, is an ideal place to resolve the above issue. The authors conducted systematic zircon U-Pb geochronological and geochemical studies on lithic sandstones and silty slates from Yangjiagou Formation in the Dakouqin area, central Jilin Province, and determined the deposition time and provenance characteristics of Yangjiagou Formation. The maximum depositional age of the formation can be constrained by the youngest weighted mean age of detrital zircons, and therefore the lower depositional ages of the two lithic sandstones samples (PM001-38-TW1 and PM001-135-TW1) from Yangjiagou Formation were determined to be (255±5) Ma and (251±2) Ma, which are consistent to the Permian and Triassic boundary (251.902±0.024)Ma. Combined with the ages of zircons that captured from the surrounding Late Triassic monzogranite dated (235-227) Ma, and the timing of the monzogranite aged (232±2) Ma which intruded in, the Yangjiagou Formation in the study area would deposit during the Late Permian. Whole rock major and trace element geochemical data of the lithic sandstones and silty slates from Yangjiagou Formation indicate that w（SiO2）ranges from 65.13% to 70.73%, w（Al2O3）form 14.75% to 17.29%, w（K2O）form 2.43% to 3.87%, w（Na2O）form 1.59% to 3.26%, and the ratio of K2O/Na2O is from 0.75 to 2.34. The light rare-earth elements are relatively enriched, while the heavy rare-earth elements are depleted, with LREE/HREE and Eu/Eu* ratios of 6.98-9.09 and 0.56-0.70, respectively. Based on the CIA-ICV diagram, the source composition discrimination diagram and the tectonic setting discrimination diagram, the sedimentary provenance of Yangjiagou Formation has experienced a relatively moderate weathering with a high maturity. The Yangjiagou Formation whose source rocks are mainly felsic, were deposited in active continental margin or continental island arc. Detrital zircon age distributions of Yangjiagou Formation can be divided into five groups: Paleoproterozoic (1 819-1 785 Ma), Meso-Neoproterozoic (1 491-561 Ma), Cambrian-Carboniferous (522-301 Ma), Early and Middle Permian (295-259 Ma), and Late Permian to Middle Triassic (258-238 Ma). Based on previous studies of regional magmatism, Yangjiagou Formation has bidirectional provenance characteristics (North China Plate and Xing’an-Mongolian Orogenic Belt). The provenance attribute and paleontological evidence of Yangjiagou Formation show a tectonic transition from collisional orogeny to a stable tectonic environment. Combined with the characteristics of magmatism in the study area, the final closure of the Paleo-Asian Ocean in central Jilin Province is considered to happen in the Late Permian-Middle Triassic.

Abstract：In order to constrain the tectonic evolution of the eastern part of the Jiao-Liao-Ji Orogenic Belt, the authors carried out a study on the petrogenesis and diagenetic tectonic background of the metamorphic gabbro-carbonatite complex in the Daxing iron mining area by using petrology, petrochemistry, petrogeochemistry and zircon U-Pb dating. The results show that the metamorphic gabbro-carbonatite complex in the Daxing iron mining area has the rock types of meta-gabbro, carbonatite and magnet ore body, and the mata-gabbro is the main rock type. Petrochemical study of the meta-gabbro showed that the w (SiO₂) is from 44.23% to 48.80%, w(Na₂O) is from 0.94% to 2.86%, w (K₂O) is from 0.51% to 1.90%, w (TiO₂) is from 0.42% to 0.93%, w(CaO) is from 8.73% to 14.78%, and the Na₂O/K₂O ratio ranges from 1.12 to 2.27，MgO/(FeO+MgO) ratio ranges from 0.54 to 0.60, (Mg²⁺+Ni²⁺)/(Fe²⁺+Fe³⁺+Mn²⁺) ratio ranges from 1.44 to 2.02, Mg/(Mg+Fe²⁺) ratio ranges from 0.60 to 0.68, and the differentiation index (DI) ranges from 11.76 to 31.79. The meta-gabbro rocks are basic-ultrabasic magma which is rich in iron and sodium, poor in potassium and titanium, and weak in differentiation. Geochemical studies show that the rocks are rich in large ion lithophile elements such as Rb,Ba[w(Rb)(4.80×10^-6-74.82×10^-6), w(Ba)(83.09×10^-6-430.10×10^-6)], and relatively rich in high field strength elements such as Hf, Th, Ta[w(Hf)(1.41×10^-6-6.20×10^-6), w(Th)(0.51×10^-6-28.91×10^-6), w(Ta)(0.47×10^-6-9.91×10^-6), and ∑REE (29.56×10^-6-812.59×10^-6)]; while, Nb is obviously depleted[w(Nb)(2.94×10^-6-36.01×10^-6) ].The (Na₂O+K₂O)/TiO₂ ratio is  0.10-5.54, Zr/Y ratio is 1.93-5.67, La/Nb ratio is 0.54-1.73, La/Ta ratio is 5.53-11.13, Nb/U ratio is 1.51-14.23.The geochemical characteristics are similar to continental tholeiitic basalts, and having the properties of intra-plate alkaline basalts. The carbonatite and meta-gabbro are interbedded.The average CaO/(CaO+MgO+Fe₂O₃+FeO+MnO) ratio is 0.98,mean w(MgO) is 0.62, and mean w(FeO+Fe₂O₃+MnO) is 0.41. It is calcareous metamagnesic carbonatite which obviously rich in Sr[w(Sr)(1 727×10^-6-1 794×10^-6)].The complex magma may come from the partial melting of the asthenosphere enriched mantle, formed in the tectonic background of the stretching of the deep fault zone in the continental plate, and assimilated and mixed with crustal materials in a certain extent during the ascent. Most of the meta-gabbro zircons have the core-rim structure, the color of the core is mostly black. It is difficult to observe its internal structure, a few of the core can be seen wide oscillating bands.The Th/U ratio is 0.23-4.19, which shows  the characteristics of basic magmatic zircon.The weighted average age of ²⁰⁷Pb/²⁰⁶Pb of the core is (2 098±11) Ma (MSWD=1.2, n=18), which represents the condensation crystallization age of the gabbro.The color at the rims of the zircons is relatively light and uniform, without zonation, and the Th/U ratio is 0.03-3.22, indicating metamorphic origin.The weighted average age of ²⁰⁷Pb/²⁰⁶Pb of the rims is (1 892±23) Ma (MSWD=2.2, n=14), which represents the metamorphic age of gabbro. Combined with regional geological data, it is considered that the eastern part of the Jiao-Liao-Ji Orogenic Belt was in a extensional tectonic environment in the Middle Paleoproterozoic, the formation of metamorphic gabbro-carbonatite complex in the Daxing iron mining area may be related to the extension during the tectonic evolution of the Songjiang-Chongshan fault zone.

Abstract：As urbanization continues to accelerate, it is difficult to acquire real-time data on potential pavement collapse hazards utilizing traditional methods. At present, efficient monitor pavement collapse has become a key challenge in the field of pavement safety. For this problem, the authors propose a method which combines time-series InSAR with wavelet transform. This method analyzes the change cycle of the subsidence point to obtain the deformation information, and  extract the temporal and spatial evolution characteristics of ground subsidence.For those areas with obvious spatial and temporal evolution characteristics, the accuracy of the InSAR results will be further verified by using the microtremor detection seismograph.We selected 52 Sentinel-1A images captured between March 2022 and November 2023 to obtain the surface subsidence results in the central urban area of Changchun by the time-series InSAR method. The results showed that the maximum deformation rate was -30.58 mm/a, and the maximum cumulative subsidence was -73.3 mm in the study area. A detailed analysis of the representative deformation area, Nanhu avenue, revealed a maximum deformation rate of -28.44 mm/a, a maximum daily average deformation rate of -0.93 mm/d, and a maximum cumulative subsidence of -47.7 mm. The analysis of significant subsidence points based on wavelet transform uncovered their subsidence evolution processes. The development of surface subsidence in severely affected areas was influenced by multiple periodic variations of different magnitudes and levels, with nested local cycles within these periodic time scales that affect the specific trends of subsidence development. Using microtremor detection seismograph to collect data from regions with obvious evolutionary characteristics, the authors generated a geological profile of Nanhu avenue. According to the profile, significant subsidence points exhibited a phenomenon of slurry infiltration.This further validated the accuracy of the subsidence monitoring results. Finally, by comparing the actual pavement collapse incident in the Nanhu avenue metro construction area to the subsidence results monitored in this study, the feasibility and accuracy of the proposed method in practical applications were validated.

Abstract：In order to explore the distribution of high quality reservoirs within the Cretaceous volcanic edifice in the M region in the eastern uplift zone of the Santos Basin, Brazil, volcanic lithology, lithofacies, stages, types of edifice and their relationship with reservoirs were studied in the Cretaceous volcanic strata in the M region, based on the drilling cores, conventional logging curves, three-dimensional seismic data and logging physical properties, with the methods of volcanic petrology and volcanic stratigraphy. The results show that four types of volcanic edifice were identified in the M region, including onshore basaltic tabular lava edifice, onshore basaltic fill-type lava edifice, subaqueous basaltic thick-layer lava edifice, and subaqueous basaltic compound lava edifice. Furthermore, the volcanic rocks in the M region were divided into five eruption stages, of which eruption stage 2(E2) is characterized by the deposition of onshore basaltic tabular lava edifice, stage 3(E3) consists of the subaqueous basaltic thick-layer lava edifice and subaqueous basaltic compound lava edifice, stage 4(E4) comprises merely subaqueous basaltic compound lava edifice, and stage 5(E5) is composed of onshore basaltic fill-type lava edifice. Additionally, the reservoir physical properties vary among four types of volcanic edifices, with the subaqueous basaltic compound lava edifice exhibiting the best properties, subaqueous basaltic thick-layer lava edifice being moderate, and the onshore basaltic tabular lava edifice and onshore basaltic fill-type lava edifice demonstrating the worst properties. Based on these findings, it is considered that in the M region, the reservoir associated with E4 featuring subaqueous basaltic compound lava edifice is the best, the reservoir of E3 comprising subaqueous basaltic thick-layer lava edifice and subaqueous basaltic compound lava edifice ranks second, the reservoirs of E2 and E5 which involve onshore basaltic tabular lava edifice and onshore basaltic fill-type lava edifice are considered the least favorable. Therefore, volcanic rocks from E3 and E4 can be targeted as key areas for subsequent oil and gas exploration in the study area.

Abstract：In order to investigate the diversity and complexity of sedimentary reservoirs, to clarify the sedimentary characteristics and sand body development rules of the Cretaceous Shushanhe Formation (K₁s) in Tahe Oilfield, Tarim Basin, and to analyze the relationship between sedimentary microfacies and reservoir sand body distribution, core analysis and logging analysis methods were used to identify lithological markers, mainly including rock color,composition, sedimentary texture, sedimentary structure, rock type and lithological associations,and to identify logging markers, including qualitative logging curve characteristics and quantitative logging data characteristics. Adopting systematic sedimentological analysis methods, mainly geological methods, we summarized lithology and logging sedimentary facies markers, and established sedimentary microfacies classification standards, and analyzed sedimentary facies types and their evolutionary characteristics vertically and on the profile through the study of single-well facies and profile facies. We also analyzed the plane characteristics of sedimentary microfacies by using ratio of sand to stratum, and the distribution pattern of sandstone in the region by using thickness of sand body. Based on the core and logging data, a sedimentary microfacies division standard was established, one single-well sedimentary facies diagram and two horizontal and vertical profile facies diagrams were drawn;while the sedimentary microfacies plane and sand body distribution of four small layers were completed, and the regional braided river delta front sedimentary model was summarized. The Upper Member of Shushanhe Formation (K₁s₃) in TP12-8 well area belongs to the shallow water gentle slope braided river delta front sedimentation system, which identifies three sedimentary microfacies of the subaqueous distributary channel, the subaqueous interdistributary channel and the channel edge，and the provenances come from the southern area of Tuofutai. Because the sedimentary environment is a large oxidized wide shallow lake basin, it has unique sedimentary characteristics. Different from the general subaqueous deposition, the color of sediments in the TP12-8 well area is oxidized, such as brown. Sand body is stacking developed, mainly fine sandstone, accounting for about 75% of the total area on the plane, and the thickness of the sand body can reach 1.4-23.9 m. The subaqueous distributary channel is the main sedimentary face in the study area, and the mouth bar does not develop. After the channel enters the lake, it continues to extend, running through the whole study area in a strip shape, with a width of 1.5-9.0 km

Abstract：Songliao Basin is one of the main basins for unconventional oil and gas exploration and development in China. The 1st and the lower part of the 2nd members of the Upper Cretaceous Qingshankou Formation are key focus layers for shale oil exploration. The research on the unclear sedimentary facies division and distribution issues of these layers in Changling Sag is beneficial for providing geological basis for shale oil exploration and selection in study area.Based on the drilling core, logging, and geochemical data of the 1st and the lower part of the 2nd members of the Qingshankou Formation in the Changling Sag of the Songliao Basin,and combining with the research results of the previous researchers, this paper conducts a detailed study of the sedimentary facies of the target layers in the study area from the aspects of lithofacies, sedimentary structure, and logging. The target strata in study area are divided into two sedimentary facies,the lake and delta facies, and four sedimentary subfacies including delta front, front delta subfacies, semi-deep lake and deep-lake subfacies. Among them, the front delta and semi-deep lake subfacies are advantageous sedimentary facies for shale oil exploration and development. The transgressive systems tract mainly develops delta front and front delta subfacies. Vertically, the two subfacies gradually slow down from bottom to top. Horizontally, the two subfacies gradually decrease towards the edge of the basin. The high water level systems tract mainly develops semi-deep lakes and deep-lake subfacies. Vertically, the two subfacies have a large thickness. Horizontally, the two subfacies extend to the center of the basin. The regressive systems tract mainly develops delta front, front delta, and semi-deep lake subfacies. Vertically, the semi-deep lake subfacies gradually slow down from bottom to top, while the thickness of the delta front and front delta subfacies gradually expands. Horizontally, the semi-deep lake subfacies decrease towards the center of the basin, while the delta front and front delta subfacies gradually extend towards the center of the basin. The dominant sedimentary facies zones mainly develop in late transgressive system tract and early regressive system tract.

Abstract：To analyze the petrological characteristics, grain size distribution characteristics, sedimentary facies types and spatial distribution regularity of the Lower Karamay Formation in Block Si 1, Karamay Oilfield, Well D16 is selected as the standard well in the study area, and its drilling cores are used as the main data source for observation and experiments. Core observation, rock mineral thin section identification and sieve analysis are used to obtain petrological data such as colors, lithologies, sedimentary structure and texture, rock mineral composition and contents, and grain size distribution statistics of the Lower Karamay Formation reservoir in Block Si 1. The sedimentary facies types of the Lower Karamay Formation in Block Si 1 are identified based on sedimentary facies markers such as core colors, lithologic assemblages,structure and texture, grain size probability accumulation curves, C-M diagram, and structural parameter scatter plots. At the same time, combined with the geophysical data of more than 100 wells in the study area, the method of well logging is used to radiate the sedimentary facies model of the D16 standard well to other wells in the study area. By pulling the well-connected profile, the distribution regularity of sedimentary microfacies and sand bodies on the profile are analyzed. According to the thickness contour map of sandstone, the distribution regularities of sedimentary microfacies and sand bodies on the plane are analyzed. The results show that the core colors of Well D16 are brown, light brown, light gray and gray-green, and the lithologies are divided into unequal-grained sandstone, medium-fine sandstone, argillaceous siltstone, silty mudstone and mudstone according to the grain size, and the sandstone is divided into lithic sandstone, feldspathic lithic sandstone and lithic feldspathic sandstone according to the rock mineral types.The roundness is sub-angular to sub-rounded, the sorting is medium to poor. Massive bedding and tabular cross-bedding are developed, the contact relationships of particles are mainly point-line contact, and the pores are mainly residual intergranular pores. The probability accumulation curves of grain size are two-stage or four-stage types, the C-M diagram has the characteristics of traction flow, and the points of the structural parameter scatter plots are concentrated in the delta plain and front interval. The sedimentary environment of the Lower Karamay Formation reservoir in Block Si 1 is shallow, weakly oxidized to weakly reduced. Two sedimentary subfacies, the braided river delta front and the shallow lake, and four sedimentary microfacies, including the subaqueous distributary channel, the subaqueous interdistributary, the estuarine dam and the coastal shallow lake mud, are identified. The main reservoir sand bodies of the Lower Karamay Formation are subaqueous distributary channel sand bodies, which are distributed in lens-shaped and layered forms on the cross section and in strip-shaped and sheet-shaped forms on the plane.

The exploration geochemical method is one of the most effective methods to quickly delineate regional prospective areas. Although this method can quickly delineate geochemical prospective areas, it often ignores the spatial variability of geochemical backgrounds, potentially missing weak geochemical anomaly. In order to identify multivariate geochemical anomaly in complex geological environments, the authors select a one-class support vector machine (OCSVM) model for this study. The model allows for high-dimensional anomaly detection without making any assumptions about data distribution. Taking the Amuhuiyilete region as an example, based on the 1∶50 000 regional geological survey results, the data of 11 geochemical elements from  stream sediments in the study area were gridded using Surfer software. The gridded “true” data were generated based on the spatial locations of known mining points in the study area. The spatial correlation between each geochemical element and the known mining points was statistically analyzed, and elements with significant correlation to the known mining points and concentrated elemental distribution were identified as prospecting indicator elements. In the study area, three indicator elements were selected. The gridded data of these three indicator elements were used as input data for OCSVM to conduct multivariate geochemical anomaly indentification research. The models were optimized using both the trial-and-test method and the artificial bee colony (ABC) optimization algorithm. The output results of both models were obtained and combined with the “true” data. Receiver operating characteristic (ROC)  curves were then plotted for the models optimized by the trial-and-test method and the ABC optimization algorithm, and corresponding area under the curve(AUC） values were calculated. The results show that the AUC value of the model optimized by the trial-and-test method is 0.879 6, while the AUC value of the model optimized by the ABC algorithm is 0.897 8. At the same time, the proportion of anomalous grids identified by the two models is 27.14% and 23.65%, respectively. This indicates that, in the anomaly detection task, the model optimized by the ABC algorithm performs slightly better than the model optimized by the trial-and-test method. The OCSVM optimized by the ABC algorithm is more effective in identifying anomalous data points, and improving the overall model accuracy. 

Abstract：Rational development and utilization of cultivated land reserve resources are essential for ensuring China’s food security, while suitability evaluation is the prerequisite and foundation. By scientifically assessing the development suitability of these resources, it provides a scientific basis for rational allocation and sustainable utilization of regional land resources.The authors take Da’an City of Jilin Province as the study area and develop a comprehensive suitability evaluation system from natural, social, and ecological perspectives. Using methods such as AHP (analytic hierarchy process), landscape pattern indices, and composite indices, the authors conduct a systematic analysis to reveal quantity, quality, and spatial distribution characteristics of development suitability levels of cultivated land reserve resources in Da’an,and propose corresponding development and utilization strategies. The research results indicate that:the development suitability of cultivated land reserve resources in Da’an City can be categorized into four levels: highly suitable, moderately suitable, marginally suitable, and unsuitable, accounting for 26.64%, 38.83%, 25.08%, and 9.44% of total area of cultivated land reserve resources, respectively. Development suitability levels gradually decrease from central part of Da’an City toward northeast and southwest. Highly suitable and moderately suitable development areas are mainly concentrated in Xinping’an Town and Haituo Township, while unsuitable development areas are mainly concentrated in Longzhao Town in southwestern part of the city. Land use types are primarily saline-alkali land and other grasslands, accounting for 99.67% of total area of cultivated land reserve resources in city. The highly suitable development areas for saline-alkali land are distributed in northwest and southeast, while the highly suitable development areas for other grasslands are concentrated in the central and western parts. Spatial distribution of development suitability levels for cultivated land reserve resources in Da’an City shows significant variation, with moderately suitable development areas being the most prevalent. Development and utilization strategies for cultivated land reserve resources should be tailored to local conditions. Saline-alkali land development should focus on water resource management and soil salinization amelioration measures, while development of other grasslands should carefully control development intensity to maintain regional ecological balance.

Abstract：To explore the geodynamic mechanisms of the large-scale magmatic activity during  Early Cretaceous in Da Hinggan Ling (Mts.), the authors focused on diabase in Huoluotai area in northern segment of Erguna Block, Da Hinggan Ling (Mts.),through the study of petrogeochemical characteristics and zircon U-Pb dating of diabase in Huoluotai area,  aimed to determine its formation age, petrogenesis, and tectonic setting. LA-ICP-MS zircon U-Pb dating results show that the weighted average age of diabase in Huoluotai area is (135.1±3.6) Ma, indicating that the crystallization age of diabase is Early Cretaceous. Whole-rock geochemical data reveal that diabase in Huoluotai area is characterized by low w(SiO₂) contents (48.84%-52.11%), high w(MgO) contents (5.13%-6.85%) and w(Fe₂O₃) contents (7.45%-8.60%). The Eu anomaly of diabase is insignificant or exhibits a weak negative anomaly (δEu = 0.83-1.06). The diabase is enriched in large ion lithophile elements (LILEs, such as Ba, Sr, and K), and depleted in high field strength elements (HFSEs, such as Zr, Ta, Nb, and Th). Diabase in Huoluotai area is only minimally influenced by fractional crystallization, crustal contamination, and accumulation processes. The Nb/Yb-Th/Yb diagram shows that diabase in Huoluotai area falls within the area of primitive mafic melts derived from subduction-modified lithospheric mantle. The Th/Nb-Ba/Th and Th/Yb-Ba/La diagrams indicate that the magma source region of diabase in Huoluotai area was modified by fluids derived from subducted slabs. The La/Nb-La/Ba diagram reveals that the magma source region of diabase in Huoluotai area is from the lithospheric mantle. The above geochemical characteristics indicate that diabase in Huoluotai area originated from a lithospheric mantle source metasomatized by fluids derived from subducted slabs. Combined with previous research, it is concluded that the formation of diabase in Huoluotai area in northern segment of Erguna Block, Da Hinggan Ling (Mts.) is closely related to the rollback process of the Paleo-Pacific Plate.

Geological hazard risk evaluation plays a significant guiding role in disaster prevention and mitigation. Focusing on the issues of frequent and severe geological hazards in Lüchun County, this study conducts a geological hazard risk evaluation to provide scientific support for disaster prevention planning and risk management in Lüchun County. Taking Lüchun County in Yunnan Province as the study area, grid unit is selected as the evaluation unit, and nine evaluation factors are chosen: elevation, slope, aspect, distance to faults, distance to rivers, engineering geological rock groups, geomorphological types, curvature, and land use types. Utilizing the spatial analysis function of geographic information system, the weighted information value model, which combines the information value model and the analytic hierarchy process, is applied to evaluate  the  susceptibility of collapse and landslide geological hazards in the studied area. The monthly average precipitation in Lüchun County is selected as the triggering factor for geological hazard evaluation of landslides and collapses in the study area. Three disaster bearing factors: population density, the number of threatened people ,  and land use types, are selected to complete the vulnerability evaluation. The hazard index and vulnerability index are multiplied then to produce the risk evaluation of collapse and landslide geological hazards. The results show that the study area can be divided into four risk levels: low, medium ,  high  and extremely high, which accounted for 12.84%, 46.01%, 38.28% and 2.87% of the studied area, respectively. The low risk areas are mainly located in the middle of Banpo Township, the north of Qimaba Township, the north of Daxing Town and the  south of Gekui Township. The middle risk areas are mainly distributed in the  north of Daheishan Town, the west of Dashuigou Township, the middle and south of Qimaba Township, the middle of Gekui Township and the southwest of Pinghe Town. High and extremely high risk areas are mainly distributed around Lüchun County and Daxing Town, Niukong Town, Sanmeng Township, Pinghe Town, and the middle of Dashuigou Township. The results of geological hazards risk evaluation obtained in this paper are in good agreement with the actual investigation.