This paper aims to conduct the first analysis and evaluation of the oil and gas geological conditions and exploration potential of the Lower Carboniferous strata in the Santanghu basin, which has the lowest level of exploration and the most uncertain resource prospects. Based on field outcrop observations, geochemical analysis, and reservoir thin section observations, the vertical sedimentary environment evolution, hydrocarbon source rocks, and reservoir geological characteristics of the target layer are revealed. The study indicates that the Santanghu basin in the Early Carboniferous was a residual back-arc basin with shallow marine sedimentary characteristics. The vertical sedimentary environment of the Lower Carboniferous strata experienced four stages of evolution: Island arc volcanic activity, closure of ancient oceans leading to semi-deep water environments, compression and uplift of continental-derived clastic sediment filling shallow water environments, and orogenic uplift basin contraction. Among them, hydrocarbon source rocks are widely distributed in the semi-deep water environment and shallow water sedimentary environment, and the organic matter type meets the standard of moderate hydrocarbon source rocks. The presence of abundant asphalt in rock thin sections also confirms that the hydrocarbon source rocks of the Lower Carboniferous not only have hydrocarbon generation ability but also have undergone a large amount of hydrocarbon expulsion processes. The Lower Carboniferous strata developed two major types of reservoirs: Igneous rocks and clastic rocks. Although the reservoirs are generally tight, the development of fractures and dissolution pores has improved the conditions for oil and gas accumulation, especially the development of granite fractures, which has a significant connectivity effect on dissolution pores. Comprehensive analysis suggests that around the hydrocarbon source rocks of the Lower Carboniferous, two types of oil and gas reservoirs can be developed: Self-generated and self-stored, and lower-generated and upper-stored. Among them, self-generated and self-stored oil and gas reservoirs are developed in structurally stable areas far from the oil source faults and have the characteristics of primary reserves. Lower-generated and upper-stored oil and gas reservoirs are developed near oil source faults within the Carboniferous system and are related to fault lithology oil and gas reservoirs.

 The exploration potential of the Panyu low uplift in the Pearl River Mouth basin (PRMB) is considerable. However, the level of research remains low and is limited to individual depressions, lacking systematic analysis of the impact of fault structures on the sedimentation of depressions and the source-sink system. This limitation hinders subsequent exploration and development activities. Therefore, this paper systematically analyzes the relationship and evolutionary sequence of the source-sink response under the control of tectonic activity in the Panyu low uplift area of the PRMB, based on the latest 3D seismic data and drilling information. The Cenozoic fault activity in the Panyu low uplift area exhibits significant zonation and periodicity under the influence of two existing fault systems, NE-NEE and NW-NWW, during the Late Mesozoic. In the Early Wenchang period, the faulting controlled the depression, with NE-NEE direction dominating in the western region and EW direction in the eastern region, while the fault activity increased during the Wenchang period compared to the Enping period. Three types of fault-controlled depressions developed within the area: Migration-type, combination-type, and inheritance-type. The source-sink system in the area utilizes the felsic granite from the uplift area and the ancient Pearl River as the material source with steep slope faults, gentle slope transition trenches, and reverse fault steps acting as transportation pathways, while half-graben depressions serve as the sedimentation zones. In the Early Wenchang period, a source-sink system dominated by nearby material sources and large source areas developed in small lake basins; In the Late Wenchang period, a coexistence of nearby and distant material sources in the small source area of large lake basins occurred; And during the Enping period, a large lake basin system developed with distant sources in the western region and nearby sources in the eastern region. Overall, the highest quality semi-deep lake facies hydrocarbon source rocks developed in the Late Wenchang period characterized by high tectonic activity rates and low material source supply; Large-scale distant deltaic sedimentary sand bodies widely developed in the Enping Formation period marked by low tectonic activity rates and high material source supply, the source rocks and the sand bodies formed the most favorable vertically combination of source, reservoir and cap rocks.

The different micro pore throat structure characteristics of tight reservoirs lead to different permeability and corresponding development strategies. Taking the Chang 6 reservoir in the Jiyuan area of the Ordos basin as an example, this study comprehensively analyzes the pore throat structure, connectivity, and fluid mobility of the tight reservoir using analysis and testing methods such as casting thin sections, scanning electron microscopy, constant velocity mercury injection, nuclear magnetic resonance, and computed tomography (CT). The study also uses core multiphase permeability experiments and real core visualization microscopic permeability experiments to study the permeability characteristics of different types of pore throat structures. Research has shown that the average porosity of the Chang 6 reservoir in the Jiyuan area is 12.1%, with an average permeability of 0.48×10-3μm2. The reservoir pore types are mainly intergranular pores, followed by feldspar dissolution pores, and are accompanied by a small amount of intercrystal pores and rock debris dissolution pores. According to the physical properties and pore throat structure characteristics of the reservoir, the pore throat structure types of the Chang 6 reservoir can be divided into three categories. Among them, Type Ⅰ is mainly composed of intergranular pores, supplemented by feldspar dissolution pores, with well-developed pores and good connectivity between throats. The movable space is developed, and the microseepage is mainly uniform. Type Ⅱ reservoirs are still dominated by intergranular pores, followed by feldspar dissolution pores. However, the proportion of intergranular pores in Type Ⅱ reservoirs decreases, while the proportion of dissolution pores increases, and the pore throat radius decreases compared to Type Ⅰ reservoirs. The connected pore structures are sparsely clustered and connected, with more developed movable spaces. Microseepage is mainly network-like. The pore types of Type Ⅲ reservoirs are mainly feldspar dissolution pores, followed by intergranular pores. The proportion of intercrystal pores increases, and the throat connectivity between effective pore reservoirs is poor. The three-dimensional pore structure space shows strong heterogeneity, and the movable space is not developed. Microseepage is mainly finger-shaped. The comprehensive analysis between macroseepage methods and microscopic pore throat structures shows that reservoir physical properties, pore throat combination methods, and degree of throat development determine different types of seepage methods. Reservoirs with good physical properties and well-developed throats have better water flooding effects, thereby improving the final recovery efficiency.

During paleoclimate analysis using sediment chromaticity, some intermediate tools are always dependent and the results are usually indirect or general. Coupling relationship study of the modern sediment chromaticity and its corresponding climate parameters can find direct climate indication of the chromaticity parameters, which is helpful to promote the chromaticity application in paleoclimate research. In this paper, 210Pb dating is used for Xinfa Reservoir Inner Mongolia sediments. Combined with the local corresponding meteorological data, the sediment chromaticity and meteorological data are statistically analyzed. Four types of sediment chromaticity-climate parameter models were found in the northern section of the Greater Khingan Mountains between 1965 and 2022. Type Ⅰ, brightness negatively indicates the average annual precipitation, redness and yellowness positively indicate the average annual temperature, which corresponds to rainless cold and gentle breeze character. Type Ⅱ, brightness negatively indicates the average annual precipitation, and positively indicates the wind speed; The redness and yellowness are negatively indicating the average annual temperature, which corresponds to rainy chilly and gentler breeze. Type Ⅲ, the brightness and yellowness negatively indicate the average annual precipitation, and the redness is weak as climate indicator, which corresponds to a temperate rainy and moderate breeze climate. Type Ⅳ, brightness negatively indicates the average annual precipitation, redness and yellowness positively indicate the average annual wind speed, which corresponds to temperate rainy and more gentle and more light-gentle breeze. Among these models, brightness is mainly influenced by precipitation, redness is mainly influenced by evaporation, and yellowness is much complex.

The Tanchang-Yawan area in Gansu Province constitutes an important antimony mineralization area of the western Qinling metallogenic belt. This study presents a comprehensive geochemical investigation of silver (Ag), arsenic (As), gold (Au), bismuth (Bi), copper (Cu), mercury (Hg), manganese (Mn), molybdenum (Mo), lead (Pb), antimony (Sb), tin (Sn), and zinc (Zn) in stream sediments, coupled with systematic antimony prospecting prediction. Results show distinctive geochemical characteristics of antimony compared to other metal elements. Fundamental geochemical parameters including element concentration Clark value, global concentration coefficient (Kk), stacking intensity (D), and coefficient of variation (Cv) of Sb demonstrate significantly higher than those of other metal elements, reflecting the high enrichment of Sb, strong post-genetic superimposition, and highly uneven distribution. It has the highest value of mineralization index （β） for Sb, revealing the best ore-forming prospect among metal elements. The Triassic strata is considered as the main ore source beds of Sb, evidenced by average Sb concentrations（3.45-10.29）×10-6 exceeding crustal background levels by 17-40 times , with the Triassic Zhalishan Formation (T1z) and Guojiashan Formation (T2gj) representing optimal ore source beds of Sb. The spatial distributions of various element anomalies are cotrlled by  regional faults, generally. The locations of Sb mineralization is highly consistent with the its enrichment center, revealing that anomaly of Sb can directely indicate the ore-forming of itself. There is a strong correlation between the mineralization of Sb and anomalies of As, Au, and Hg, so that Sb-As-Au-Hg act as a combined prospecting geochemical indicator for antimony prospecting. According to the distributions of anomaly of antimony and indicator established in this study, 10 antimony perspecting target areas were divided into Tanchang-Yawan area, and 6 antimony mineralization points were newly found.

The Shilu large-scale Cu-Mo skarn deposit in western Guangdong is situated along the northwestern margin of the Yangchun basin within the Yunkai area. The orebodies are predominantly hosted in skarn and skarnized marble at the contact zone between Early Cretaceous granodiorite and Lower Carboniferous strata, structurally controlled by NE-trending faults. To better understand the metallogenic processes, this study employs EPMA and LA-ICP-MS in-situ microanalysis methods, focusing on garnet and vesuvianite to investigate their elemental geochemical characteristics based on detailed detailed geological investigations. Analytical results demonstrate that: Garnet in the Shilu deposit is predominantly andraditic (Gro0-36And63-100), while pyroxene is overwhelmingly diopside (Hed0-14Jo0-6Di81-99); The mineral assemblage indicates early-stage fluid evolution occurred under high oxygen fugacity conditions;  Vesuvianite exhibits more complex compositions, primarily belonging to common vesuvianite with minor Al-rich, Mg-Al, and Mg-Fe varieties. Garnet formed in a weakly acidic, open-system environment characterized by high water/rock ratios and dominantly infiltrative metasomatism. Both garnet and vesuvianite mainly originated from magmatic-hydrothermal fluids associated with granodiorite and quartz diorite. During the transition from skarn to retrograde alteration stages, the fluid composition shifted from Fe3+-rich to Al-rich, accompanied by significant reduction in w(∑REE). This trend reflects changing physicochemical conditions (e.g., pH) and suggests the involvement of external fluids (e.g., meteoric water) into the open-system alongside magmatic fluids. Additionally, the study identifies considerable tungsten exploration potential but limited tin mineralization potential in the deposit.

The gold bearing granite porphyry in Xiacaodi Village, Jiuzhaigou County is located in the western extension of  Yangshan gold deposit belt in the West Qinling. In order to explore the relationship between magmatic activity and gold mineralization in this metallogenic extension zone, as well as characterize the parent rock of the ore bearing granite porphyry, petrographic, geochemical, and LA–ICP–MS zircon U–Pb dating studies were conducted on the gold bearing granite porphyry. The results indicate that the granite porphyry belongs to the calcium alkaline series, characterized by rich silicon aluminum and poor iron magnesium calcium; The trace elements are characterized by enrichment of K, Rb, Cs, U, Pb, while the mass fractions of Nb, Ta, Zr, Hf, Ti and other elements are low, while Ba, Sr, Nb, Ti and other elements are deficient. The δCe is 0.91 to 0.98, which is similar to the distribution pattern of volcanic arc granite, indicating genetic association with subduction collision environments; The total amount of rare earth elements is 74.78% to 90.28%, with characteristics of light rare earth element enrichment and heavy rare earth element depletion; The δEu value ranges from 0.62 to 0.79, indicating weak loss of europium and belonging to peraluminous granite. Zircon U-Pb dating yielded four distinct age populations: (217.7±2.2), (222.3±5.2), (216.5±5.5), and (758±11) Ma. Combined with previous comparative analysis of geochemical, isotopic, and other data from intermediate acidic intrusive rocks (veins) in  Yangshan gold belt, it is believed that the gold mineralization in  Yangshan gold belt is closely related to the Late Indosinian magmatic activity, and the granite originates from partial melting of the basement rocks (Bikou Group) in a collision environment. The granite porphyry in Xiacaodi Village is a typical post magmatic hydrothermal gold deposit type within  Yangshan gold belt. This type of granite porphyry rich in silicon and aluminum is a horizontal metallogenic indicator for gold prospecting, while vertically it may overlie gold-bearing bodies genetically related to early-stage intermediate-acidic veins in its lower part.

The Fengning Xingyuan superlarge fluorite deposit in Hebei Province is located in the western section of the north Hebei-west Liaoning fluorite metallogenic belt. While previous studies have established fundamental geological characteristics of the deposit, but the formation age, metallogenic dynamics background, material sources and genetic classification of the deposit are still unclear. This study integrates zircon U-Pb dating, rock geochemical analysis and Sr-Nd isotope studies of the mineralised granite porphyry, building upon comprehensive field investigations. The results show that fluorite mineralization occurs within granite porphyry veins and their hanging wall/footwall of fracture zones, exhibiting vein, reticulate-vein, breccia, and banded structures, and accompanied by pervasive silicification and sericitization of surrounding rocks. Zircon U-Pb dating yields an Early Cretaceous age (（137.9±3.4） Ma) for the granite porphyry, which displays distinctive geochemical features of high silica (w(Si2O)=72.48%-75.70%), high alkalinity (w(Na2O+K2O)=5.28%-10.23%), calcium-poor (w(CaO)=0.35%-2.52%), magnesium (w(MgO)=0.10%-1.47%), belonging to the peraluminous, calcium alkali-potassium basalt series. The trace element spider diagrams show enrichment in Rb, Th and Zr but depletion in Sr, Ba, Nb and Ta, and the relative enrichment of light rare earth elements and the strong Eu-negative anomalies, toghther indicating A-type granite characteristics. Integrated with regional tectonic evolution, these features suggest the granite formed during large-scale extension and thinning of the North China craton. The Sr-Nd isotopes show that the granite porphyry likely originated through partial melting of crustal source materials. The geological and geochemical characteristics of the deposit suggest that the Ca in the mineralizing fluids originates from the hydro-rock interaction between the hydrothermal fluid and the volcanic host rocks/Ca-rich strata, while the F derives principally from the magma, and the deposit constitutes a medium-low-temperature magmatic-hydrothermal fluorite deposit genetically related to the granite porphyry.

The Benxi area, situated within the northeastern segment of the eastern block of the North China craton, represents a critical region for investigating Archean evolution and holds significant importance for understanding the formation and evolution of the Precambrian continental crust of the North China craton. To elucidate the petrogenesis and tectonic setting of the newly identified Liujiapuzi pluton in Benxi (within the Jiao-Liao-Ji orogenic belt), an integrated study of petrology, whole-rock geochemistry, and zircon U-Pb geochronology was conducted. The Liujiapuzi pluton is compositionally defined as porphyritic fine- to medium-grained biotite monzogranite, displaying metaluminous to weakly peraluminous characteristics and high-K calc-alkaline affinities typical of I-type granite. Geochemically, it exhibits enrichment in large-ion lithophile elements (e.g., Sr, La, Th) and depletion in high-field-strength elements (e.g., Nb, P), with a right-sloping REE pattern and negative Eu anomaly. Zircon U-Pb dating yields an emplacement age of ((2 518±21) Ma), indicating formation during the Late Neoarchean. Petrogenetic modeling suggests a hybrid magma source involving crustal assimilation with mantle-derived components, generated in an active continental margin environment characterized by oceanic subduction. This implies the Longgang and Langlin blocks of the eastern North China craton were not amalgamated at ((2 518±21) Ma). The Liujiapuzi pluton represents an early accretionary product distinct from the post-collisional Majiagou pluton ((2 490±21) Ma) in the same area. This event likely represents the last major magmatic episode before stabilization of the Archean basement in the North China craton.

Great Xing’an Range is located in the eastern part of the Central Asian orogenic belt. It is a composite part of the Paleo Asian Ocean, circum Pacific Ocean and Mongolia Okhotsk Ocean. Having strong tectonic magmatic activity, it is the best window to study the Mesozoic tectonic magmatic evolution in Northeast China. The authors studied the Jurassic granitoids in the Jinjianggou of Central Great Xing’an Range, and performed systematic analyses of zircon U-Pb chronology and whole-rock elemental geochemistry. The zircon U-Pb age data indicate that petrogenic ages of medium-fine grained granodiorite is (165±1)Ma, the diagenetic ages belong to Middle Jurassic, the petrogenic ages of medium-fine grained syenogranite and medium-coarse grained monzogranite are (152±1)Ma, (147±1)Ma and (148±1)Ma, with their diagenetic ages belong to Late Jurassic. Geochemical data show that the granodiorite and monzogranite samples have low silicon, and are poor in magnesium, iron and titanium, TFeO/MgO ratio and Zr/Hf ratio; They are enriched in Th, Rb, U, Ce, La, Hf and poor in Sr、Nb、Ba、Ti、P, and have geochemical characteristics of type I granite. The magma was originated from the source area of partial melting of igneous material in the lower crust. The syenogranite samples are enriched in silicon, high in potassium, poor in magnesium, iron and titanium, low in TFeO/MgO ratio and Zr/Hf ratio, relatively high in differentiation index, strong europium negative anomaly, relatively rich in Th, Rb, U, Hf, Ce, La, Nd elements, and deficient in Sr, Nb, Ba, Ti, P and other elements, and has geochemical characteristics belonging to highly differentiated type I granite. The magma was originated from the source area of partial melting of igneous material in the lower crust. Combined with the chronology and geochemical characteristics, the medium-fine grained granodiorite was formed in the syn-collision tectonic setting, and medium-fine grained syenogranite and medium-coarse grained monzogranite were formed in post-orogenic extensional tectonic environment, which were related to the scissor closure of the Mongol-Okhotsk Ocean from west to east. We believe that the final closing time of the western section of the Mongol-Okhotz suture zone is the Late Middle Jurassic.

Understanding the formation and source characteristics of andesite in continental arc environments holds significant implications for revealing arc magmatism. This study focuses on the Suolun area of the Great Xing’an Range, using a combined approach of chronology and geochemistry to thoroughly investigate the genesis of trachyandesite and andesite in the region and their magmatic source characteristics. Zircon U-Pb dating indicates that the trachyandesite and andesite formed during the Early Cretaceous (134-129 Ma). The studied andesite and trachyandesite have SiO2 contents of 57.13% to 58.16%, total alkali (K2O+Na2O) contents of 6.10% to 6.40%, Al2O3 contents of 17.09% to 17.59%, TFe2O3 contents of 6.71% to 6.92%, and Mg# values of 41.52 to 43.94, featuring high-potassium calc-alkaline weakly peraluminous rock characteristics. These samples exhibit enrichment in light rare earth elements and large ion lithophile elements (such as K, Rb, Ba) and relative depletion in high field strength elements (such as Nb, Ta, P, and Ti), with a slight negative Eu anomaly (δEu=0.88- 0.89), indicating that they are products of continental arc magmatism. Additionally, both types of samples have high zircon εHf(t) values (5.81 to 11.29) and whole-rock εNd(t) values (0.6 to 1.3), suggesting that the intermediate magmas in the Suolon area originated from partial melting of a subduction-fluid-modified, depleted lithospheric mantle fluids.

In order to investigate the beneficial effects of the combined drilling process of down-the-hole hammer and impact drilling, in this paper, the rock fragmentation process between rock and impact hammer head before and after the arrangement of small drill holes and under different hole diameters was investigated based on the HJC （Holmquist-Johnson-Concrete） constitutive model and the intrusion analysis method in the numerical simulation of LS-DYNA. At the same time, the rock fragmentation efficiency between the impact hammer drilling alone and the combined drilling process was quantitatively investigated in conjunction with the trial drilling test on site of the Jinyu Bridge in Quanzhou. The simulation results show that, with a constant number of small boreholes, as the diameter of the small boreholes drilled in the rock mass increases, the volume fraction of damaged rock mass increases. The increase in the diameter of the small boreholes reduces the energy required to break the unit volume of rock, which is beneficial for improving the fragmentation effect of the rock mass. The efficiency of energy transfer is related to the contact area between the impact hammer head and the rock. Under a constant number of small boreholes, an increase in the diameter of the small boreholes enhances the efficiency of energy transfer. However, beyond a certain value, an increase in the diameter of the small boreholes becomes unfavorable for the effective transfer of energy. During the process of the impact hammer impacting on the rock formation, the stress wave spreads out to the deeper part of the rock with time and gradually forms five  elongated fissures radiating from the center to the periphery. In addition, the results of on-site trial drilling tests show that the drilling efficiency of the combined drilling process can be improved by 54.47% on average compared with impact drilling alone. Comprehensive analysis shows that the implementation of the combined drilling process of down-the-hole hammer and impact drilling rig is conducive to improving the efficiency of rock crushing on site.

By using the large-scale model test system, the indoor model tests in the clay soil were carried out, and the macroscopic phenomena of the penetration characteristics of the static piles in the clay soil were obtained. In order to solve the problem of macro and meso mechanical response of the pile body during the pile driving process of the static pressure pile, the continuous penetration process of the static pressure pile was simulated by using two-dimensional particle flow numerical simulation software, and the variation law of the pile pressure force, the pile end resistance and the pile side friction resistance during the static pressure pile penetration process were studied at the fine level. The test results show that the mechanical characteristics of the static pressure pile are closely related to the diameter of the pile, the larger the pile diameter is, the greater the lateral extrusion pressure on the soil, the more obvious the lateral friction resistance of the pile, and the greater the pile compression force. With the increase of the depth of soil entry, the horizontal contact force chain of the soil at the position of the adjacent pile body increases, and the horizontal force chain closer to the pile end is larger, and the dense area of the contact force chain of the soil at the pile end shows a circle.

In order to find selenium rich soil quickly, efficiently and accurately using selenium free data, it is necessary to build the best model to predict selenium rich soil. 502 data sets were selected from 1 277 1∶50 000 surface soil geochemical data. With w(Zn),w(K2O),w(P),w(Mo),w(Mn),w(Cr),pH,D（Devonian） as independent variables and Se rich or not as dependent variables, SPSS Modeler 18 software was used to build binary Logistic regression model, multi-layer perceptron neural network model, random forest model and support vector machine model (linear, multinomial, radial basis function, Sigmoid) for predicting Se rich soil, and the measured data of 35 soil samples were used for verification. The results show that, using binary Logistic regression model, multilayer perceptron neural network model, random forest model and support vector machine model (linear, polynomial, radial basis function, Sigmoid), the overall accuracy of prediction and verification of the seven prediction models and were 88.8% and 94.3%, 91.0% and 97.1%, 96.6% and 97.1%, 87.9% and 97.1%, 86.1% and 94.3%, 86.9% and 94.3%, 80.3% and 91.4%. The AUC were 0.948, 0.950, 0.993, 0.937, 0.945, 0.928 and 0.873, respectively. The accuracy and stability of the random forest model are the best. Meanwhile, this study identified clean selenium-rich soil and green selenium-rich mountain rice, indicating that this method is feasible in the prediction of selenium-rich soil, and it can be further extended to geological prospecting and environmental monitoring.

In recent years, the number of waste tires has continued to increase, and finding a reasonable way to dispose of waste tires has become an urgent problem. To find a way to deal with a large number of waste tires, this paper investigates the feasibility of using rubber fibers to improve expansive soil. Firstly, Direct shear tests were employed to investigate the effects of different rubber fiber contents on the mechanical characteristics of expansive soil. Then, a strength prediction model for rubber fiber reinforced expansive soil was developed based on the discrete model. The results shows that there is an enhancement in the strength of rubber fiber reinforced expansive soil with 5% and 10% fiber content compared to expansive soil, with the maximum strength enhancement at 10% rubber fiber content. Rubber fibers enhance the cohesion of expansive soil and have little effect on the internal friction angle. When the rubber fiber content is 15%, the rubber fibers adhere to each other and the fibers cannot be completely covered by the soil particles, which produces faults in the soil particles and thus reduces the soil strength. A strength prediction model for rubber fiber-reinforced expansive soil is proposed based on the discrete model, which effectively predicts the shear strength of rubber fiber-reinforced expansive soil.

Selecting an appropriate method for assessing natural background levels (NBL) in groundwater is crucial for objectively understanding the NBL in groundwater. On the basis of reviewing the development process of NBL in groundwater, this article focused on summarizing the current methods for the assessment of NBL in groundwater with their advantages and disadvantages, and pointed out the development trend of the assessment for NBL in groundwater in the future. The methods for assessing NBL in groundwater can be roughly divided into five categories: Methods based on uncontaminated groundwater samples, pre-selection methods, statistics methods, exploratory data analysis methods based on graphs, and the combination of multi-methods. The method based on uncontaminated groundwater samples has been rarely adopted due to its inherent limitations. Pre-selection and statistics method are two commonly used independent methods in the study of groundwater NBL. Generally, the former one is more subjective than the latter one. Nowadays, the combination of multiple methods becomes a development trend in the research of groundwater NBL assessment, because some limitations of one method for assessing groundwater NBL may be avoided by the combination with another method. Among them, the combination of pre-selection and statistics methods is the most common way of combination. In addition, the combination of emerging exploratory data analysis methods based on graphs with pre-selection methods and/or statistics methods is commonly better than the combination of pre-selection and statistics methods. However, the use of the former combination often requires a good understanding of the hydrogeochemical characteristics in study areas. Therefore, the former ones for assessing groundwater NBL are less convenience and universality in comparison with the latter ones.

In order to realize the fluoride solidification/stabilization of the lake and reservoir sediment, a compound of calcium hydroxide, potassium dihydrogen phosphate, iron sulfate and magnesium chloride was designed. Response surface methodology optimization experiments were conducted with the solidification/stabilization efficiency of fluorine-containing sediment as the dependent variable, and the calcium hydroxide addition, potassium dihydrogen phosphate addition, ferric sulfate and magnesium chloride addition as the independent variables. The results showed that the optimal solidification/stabilizing agent ratio was 3.572% calcium hydroxide, 4.342% potassium dihydrogen phosphate, 3.391% iron sulfate and 3.391% magnesium chloride. Using the optimal conditions simulated by the response surface method, experimental verification showed that the fluorine solidification/stabilization efficiency in the dredging sediment can reach 73.91%. The predicted value of 75.62% is in good agreement, indicating that the model is reliable and effective.

The production and living water of residents in Naozhou Island is mainly groundwater. In recent years, due to large-scale exploitation, groundwater in the region has been polluted to varying degrees. In order to explore the current situation of drinking groundwater source in Naozhou Island, this study comprehensively used mathematical statistics, piper three-line diagram, Gibbs diagram, ion ratio analysis and isotope analysis to study the water quality status, hydrochemical characteristics and genetic mechanism of 46 shallow groundwater points in Naozhou Island. The results show that the groundwater in the study area is generally neutral and weakly acidic. The cations of groundwater are mainly Na+ and Ca2+, and the anions are mainly HCO3- and Cl-. About a quarter of the points are saline water. The hydrochemical types are mainly mixed Cl-Ca·Mg type, Cl-Ca type and HCO3-Na·Ca type. The hydrochemical composition of shallow groundwater in the island is mainly affected by the combined effects of rock weathering and evaporation concentration, and some sites are affected by seawater intrusion.

As the oldest seamount and the biggest guyot found in the South China sea (SCS) central basin, Guanshi guyot is located on the 17°N fossil spreading center near the Manila trench. The dredged plagiogranite sample on Guanshi guyot shows trace element and isotopic composition similar to those of mid-oceanic ridge basalts (MORB), and its pyroxene and whole-rock 40Ar/39Ar dating yields ages of (32.3±0.5) Ma and (28.9±1.9) Ma, which is inconsistent with popular research acquired from marine magnetic anomalies identifying (~23.6 Ma). So further study is required to inspect the opening history of SCS central basin. The density of the dredged plagiogranite sample is measured for many times, which ranges from 2.757 3 to 2.941 6 g/cm3, and the median density is 2.846 5 g/cm3. The stratum velocity field originated from multi-channel seismic (MCS) data is used to transform the time-domain MCS interpreting data into the depth-domain. By creating many crust density models across Guanshi guyot with constraint of the depth-domain sediment basement and gravity anomalies, we infer that the most possible internal density of Guanshi guyot  mainly ranges from 2.70 to 2.75 g/cm3, higher than the average density of younger seamounts with SCS central basin (2.60-2.70 g/cm3), and lower than the average density of gabbro from lower oceanic crust (2.80-2.90 g/cm3). To be precise, higher density (>2.80 g/cm3) rock which can be drilled in the local area in the southern part of Guanshi guyot can’t be excluded in this study. Comprehensive considering the crust density models across Guanshi guyot, MCS interpreting data, and life cycle of seamount, we infer that Guanshi guyot is an intraplate seamount (or oceanic island) during the seafloor spreading period of SCS central basin. Further studies have to be done to understand the relationship between dredged plagiogranite sample and Guanshi guyot. For better understanding the origin of the plagiogranite during the evolution of intraplate seamount, a more reasonable tectonic model should be explored.

Deep learning-based methods for multiple attenuation have been a pivotal research focus in the field of seismic data processing. Traditional supervised neural networks are data-driven and rely on direct end-to-end mapping. The physical interpretability of the network model outputs is limited, and the effectiveness of multiple attenuation is constrained by the quality of labeled seismic data. This paper proposes an improved deep learning method that integrates the time-spatial physical information of 3D seismic data volume as prior knowledge with the neural network output to construct an implicit polynomial of multiple and full-wavefield. In this approach, the output of the neural network is not labeled seismic data but coefficients of polynomial function space. By incorporating prior knowledge into the loss function and minimizing this loss function, an implicit polynomial of multiple and full-wavefield is derived. This approach obviates the matching subtraction process in surface-related multiple attenuation. The results of synthetic and field data demonstrate that the proposed method surpasses traditional end-to-end deep learning methods in terms of efficacy and accuracy in free surface-related multiple attenuation.

The main gas-bearing layer of Zhongmu sag has a relatively well-developed medium-small scale fractures. The complex geological structures in this area, coupled with the shielding effect of the coal seams, have led to both the resolution and the signal-to-noise ratio of the seismic exploration results being lower than the ideal values. The fracture parameters predicted by conventional methods are insufficient to characterize the development of local medium-small scale fractures. This has led to the need for a more suitable method. To address this issue, this paper refined and enhanced the 3D seismic data using maximum likelihood techniques to obtain the initial fracture orientation and fracture density. Based on the initial fracture orientation and density, the orientation guidance field was established, and a random discrete fracture network model was calculated through the orientation guidance field and fracture density. The random discrete fracture networks were connected to establish continuous random discrete fracture network models tailored to Zhongmu area, thereby reflecting the development patterns and distribution characteristics of medium-small scale fractures. And a comparative analysis was made between random discrete fracture network models and continuous random discrete fracture network models. It indicates that the threshold of the connected fracture distance has a significant impact on the modeling of random discrete fracture networks. The network of medium-small scale fractures in Zhongmu area is predominantly orientated in the direction of NEE, i.e., the azimuth of 60°-80°. The random discrete fracture network is coincided with the fractures in the layer. The orientation of the rose diagrams of the fractures located in the surrounding wells is well consistent with that of the fracture network model. The model yielded positive results in fracture prediction within the Lower Paleozoic fracture-developed zone of a pilot area in the south North China basin.

Rock thermal physical properties are key parameters in the fields of geothermal, engineering geology, and oil and gas geology. In order to have a clear understanding of the influence of factors such as pore fluid medium and saturation on the thermal conductivity of clastic rocks, in this study, typical clastic rock samples from the Cenozoic of  Qaidam basin were selected, and their thermal conductivities were measured by applying the unsteady state method. The thermal conductivity of clastic rocks decreases with the increase of porosity, and the decrease of thermal conductivity can be up to 37.6% in the samples of dense reservoirs with porosity lower than 5.0%. The thermal conductivity of  clastic rocks showes a significant positive correlation with the saturation degree, and the effect of water saturation on  transverse and longitudinal thermal conductivity is more significant than that of oil saturation. The ranges of thermal conductivity anisotropy coefficients of clastic rocks in dry state and in water-saturated state are 0.648-1.546 and 0.840-1.200, respectively, indicating that the saturation degree has an attenuating effect on the anisotropy of thermal conductivity. The greater effect of quartz content on the thermal conductivity of the rocks and the brittleness of the quartz-rich clastic rocks result in more developed microfractures in the rock samples, whereas microfractures in situ formation are usually saturated with pore fluids, it is hypothesized that the development of fractures negatively affects the actual stratigraphic thermal conductivity and its anisotropy in dry conditions, but under water-bearing conditions, groundwater convection along the microfractures significantly increases the thermal conductivity.

Forest ecosystems play an irreplaceable role in terrestrial ecosystems. The cross-border forests among China, North Korea, and Russia have abundant forest resources, providing wide habitats for numerous wildlife and plants. Scientific evaluation of forest health not only helps to protect and manage natural resources, but also effectively maintains biodiversity and promotes regional sustainable development. This article takes the border area among  China, North Korea, and Russia as the object, uses subjective and objective weighting methods to determine the initial weights of each evaluation indicator, and uses game theory to combine and optimize the weights. After determining the weights, based on the principle of extension, a matter-element extension model is constructed to evaluate the long-term forest health status. This research has shown that: 1) The weight allocation optimized through game theory shows that the vitality indicator dominates the four major categories of indicators in the indicator system, with a weight of 51.85%. This highlights the importance of vitality in forest health assessment, followed by indicators of system resilience (18.16%), site condition (16.43%), and soil quality (13.56%). 2) The results of the three periods in 2000, 2010, and 2020 show that the forest in the research area has the highest proportion of moderate health status, followed by good health status, and the lowest proportion of unhealthy status, with 16.50%, 15.53%, and 15.42%, respectively, showing a downward trend. This reflects that although some areas are in an unhealthy state, the forest health status is developing towards a better direction. 3) For many years, the multi-temporal and spatial characteristics of forest health in the research area have been dominated by a moderate health steady state, reflecting the stability of forest health. However, there are significant regional differences. In some regions of China, fluctuations coexist with high-quality steady states. While in North Korea, low steady states dominate but show signs of improvement. The health status of the western and eastern regions of Russia is diverse.

The U-Net encoder-decoder network structure is used to partition most buildings in mining areas, but the encoder-decoder structure does not make full use of the semantic and spatial features, resulting in low segmentation accuracy. Aiming at the defects of existing building extraction methods, a semantic spatial consistency semantic segmentation network (SSC-SeNet) is proposed. Firstly, the network uses a multi-channel structure to extract and integrate semantic features, spatial features, and consistency features. Secondly, a space extraction channel is introduced in the first three coordinate convolution of the main channel, and a Gabor Fourier filter is designed for further extraction of spatial features. Then, a semantic extraction channel is introduced at each layer of conventional convolution blocks in the main channel to improve the capability of semantic feature extraction. Finally, the feature fusion module is used to fuse the features of spatial extraction channel, semantic extraction channel and main channel, and the final segmentation image is generated. Experiments on the building data set of Xiangtan manganese mine with a resolution of 0.03 m show that the crossover ratio of SSC-SeNet is as high as 88.47% and the overall accuracy is 97.09%, both of which are ahead of mainstream traditional networks such as U-Net, and overfitting problems are overcome due to its lightweight characteristics.

Plane porosity is a key indicator for assessing the quality and resource potential of tight reservoirs. The current reservoir pore intelligent extraction and plane porosity calculation methods based on single image analysis technology have problems such as cumbersome pre-configuration, weak learning ability of sparse samples, and low accuracy of complex pore morphology recognition. For this reason, this paper proposes an intelligent calculation method of plane porosity in tight sandstone thin section by integrating SOLO (segmenting objects by locations) v2 algorithm and OpenCV (open source computer vision library) based on the idea of hybrid intelligence. Using the instance segmentation algorithm SOLOv2 to segment and label the pore regions in the image, and the distribution and percentage of pores are extracted in combination with OpenCV, then the plane porosity is calculated. Comparative experimental results show that this method is superior to the comparative algorithms such as YOLACT (you only look at coefficients), Mask R-CNN (mask region-based convolutional neural network) and SOLO in terms of Dice coefficient (0.88), pixel accuracy (0.91), and plane porosity calculation error (<0.1), with a faster execution speed.