To determine the stratigraphic position of the Naitoushan marble in the eastern margin of the Changbai Mountains basalt-covered area, the authors conducted a study on its paleosedimentary environment using petrology and petrochemistry. The results show that the main rock types of the Naitoushan marble are medium-thick bedded marble and medium-thin bedded dolomitic marble, indicating formation in a coastal-shallow marine evapora tive environment slightly closer to the continent. The w (SiO2 ) of the major elements ranges from 2. 04% to 6. 21%, with a correlation coefficient of 0. 38 between SiO2 and Zr, suggesting that the SiO2 content is not signifi cantly related to terrigenous detritus and is mainly of chemical sedimentary origin. The w (MgO + CaO + LOI) ranges from 91. 37% to 96. 77%, indicating that the rock is predominantly composed of carbonate minerals with minimal detrital components. The CaO/ MgO ratio ranges from 1. 41 to 24. 34, suggesting deposition in a relatively enclosed coastal-bay marine environment. The Fe3+ / Fe2+ ratio is between 0. 05 and 0. 80, possibly reflecting for mation in a relatively dynamic and weakly neutral environment. Trace and rare earth elements analysis show that the correlation coefficient between Ce anomaly (Ce/ Ce∗) and Eu anomaly (Eu/ Eu∗) is-0. 46, and-0. 25 with total rare earth elements (REE). The Mn/ Sr ratio ranges from 0. 01 to 0. 05, indicating that the rare earth elements in the marble samples from the study area were hardly affected by diagenesis. The correlation coefficient between Zr and Th is 0. 75, 0. 14 with ∑REE, 0. 47 with Ce/Ce∗, and-0. 48 with Eu/Eu∗, indicating that the REE distri bution in the marble samples was barely affected by external materials. The Ce/ Ce∗ ratio of 0. 82-1. 00 indicates a weakly oxidizing environment during marble formation. The (Tb/ Pr)N ratio of 1. 02-3. 13, and the (Tb/ Yb)N ratio of 0. 96-1. 56 indicate a slight enrichment of middle rare earth elements, suggesting possible hydrothermal input. The average Eu/ Eu∗ value is 1. 17, with correlation coefficient of 0. 12 with Fe2+ and 0. 56 with Mn2+ , and 0. 20 with (Fe2+ + Mn2+), also implying hydrothermal influence. The average Gd/ Gd∗ is 1. 05, indicating that human factors in sample testing have been basically excluded. The Y/ Ho ratio ranges from 31. 53 to 44. 00, with an average of 35. 17, suggesting formation in a inshore or restricted marine environment. Combined with regional geological data, it is believed that the Naitoushan marble was formed in a relatively closed coastal-shallow marine environment under oxidized to weakly oxidized seawater, accompanied by hydrothermal input. The rock assemblage is correlated with the lower part of the Zhenzhumen Formation, representing its eastern extension.

 The magmatic rocks exposed in Xiyinkeng area (Jurong City, Jiangsu Province) belong to the Anjishan complex. The rock type is mainly granodiorite porphyry, which is intruded by a small amount of intermediate-basic dykes such as quartz diorite porphyrite, diorite porphyrite, and diabase porphyrite. To determine the timing of mag matism (crystallization/ emplacement age) and geodynamic background, this paper conducted petrographic, zircon U-Pb chronology, and geochemical characteristics research on Xiyinkeng magmatic rocks. Zircon U-Pb dating in dicated that granodiorite porphyry crystallized at (104. 45 ±0. 29) Ma, followed by the emplacement of quartz dio rite porphyrite at (104. 66 ±0. 52) Ma, and subsequently diabase porphyrite intrusion at (101. 37 ±0. 34) Ma, all occurring during the Early Cretaceous. Geochemical data show that the magmatic rocks in Xiyinkeng area are characterized by high potassium [w (K2 O) 1. 96%-4. 05%] and high alkalinity [w (Na2 O) 2. 29%-4. 68%], with A/ NK values ranging from 1. 38-2. 15, A/CNK values ranging from 0. 62-0. 96, and Littmann indexes ranging from 1. 76-2. 59, indicating that they are metaluminous calc-alkaline series I-type granites. The diabase porphyrite exhibits higher rare earth elements enrichment (ΣREE = 144. 61 × 10-6- 182. 84 × 10-6, avg. 163. 73 × 10-6), with LREE/HREE, (La/Yb)N , and (Gd/Yb)N ratios of 10.81-12.76, 13.60-17.62, and 2.16 2. 33, respectively. In contrast, the rare earth element contents of granodiorite porphyry, quartz diorite porphyrite and diorite porphyrite are lower than those of diabase porphyrite (ΣREE = 94. 43 × 10-6-143. 47 × 10-6, avg. 118. 79 × 10-6). The light and heavy rare earth element ratios (LREE/ HREE) range from 14. 43-24. 48, the (La/ Yb)N and (Gd/Yb)N are 22. 16-43. 70 and 2. 57-2. 87 respectively. The rocks are relatively enriched in large ion lithophile elements (Rb and La) and relatively depleted in high field strength elements (Nb, Ti and Ta), showing obvious characteristics of island arc magmatic rock. The Nb/ Ta ratio is 11. 57-24. 68, which is close to that of continental crust, indicating the presence of a large amount of crustal material. Combined with previous research results, it is believed that the magmatic rocks in the Xiyinkeng area was formed in a back-arc extensional environment during the subduction and retreat of the Pacific Plate. It is the product of interaction between the lower crust and mantle materials, classified as crust-mantle granite.

Carboniferous volcanic rocks in Dabasong area of Junggar Basin are widely distributed and change rapidly in lateral direction. It is the key to study the reservoir to clarify the spatial distribution law of Carboniferous volcanic rocks. However, in the process of exploration, it is found that the lithology of volcanic rocks is complex, the volcanic edifices are incompletely preserved, and the eruption cycles are frequent. Based on core observation, conventional logging curve data, isotope chronology data and three-dimensional seismic data of 6 wells, the authors divide volcanic eruption cycles, depict volcanic edifices and lithofacies, analyze the matching relationship between volcanic rocks distribution and fracture, and the oil and gas geological significance of volcanic eruption cycles. The study shows that the Carboniferous volcanic rocks in the Dabasong area can be divided into four cycles: basic cycle 1 (323-319 Ma) develops basalt and basaltic tuff, with a thickness of about 425 m. The intermediate cycle 2 (311 310 Ma) is andesite and andesitic tuff, with a thickness of 414 m. The intermediate-acid cycle 3 (310-306 Ma) develops dacitic tuff and andesite, with a thickness of 281 m. The acid cycle 4 (306-304 Ma) is rhyolitic tuff with a thickness of about 174 m. The seismic explanation show that the volcanic edifices in the Dabasong area can be divided into basic shield-shaped and intermediate-acid mound-shaped volcanic edifices. The basic volcanic rocks in cycle 1 are widely distributed and the overall thickness is large. The volcanic edifices are mainly basic shield shaped volcanic edifices, and the distribution is mainly controlled by the NE-SW fault in the middle and late Hercynian. The intermediate volcanic rocks in cycle 2 are the most widely distributed, and their distribution is mainly controlled by the NE-SW fault in the middle and late Hercynian. The volcanic edifices are mainly interme diate-acid mound volcanic edifices, and the volcanic rocks are mostly central eruption. The intermediate-acid volcanic rocks are distributed in cycle 3. The volcanic rocks are dominated by central eruptions with multiple thick ness centers, and the overall thickness is large. The volcanic edifices are dominated by intermediate-acid mound volcanic edifices. The volcanic activity of cycle 4 is weakened, and the distribution area of volcanic rocks is signifi cantly reduced. The analysis of physical properties shows that the high-quality reservoirs of volcanic rocks in cycles 2 and 3 are developed, and the physical properties of volcanic rocks are good, which can be used as a favorable horizon for the exploration of volcanic oil and gas reservoirs in the Dabasong area.

Banded iron formation (BIF) is an important type of iron deposit formed during the early evolutionary history of the Earth. The Naxiguole BIF deposit is situated in the western segment of the East Kunlun Orogenic Belt. It is hosted within a medium-to high-grade metamorphic plagioclase amphibolite assemblage of the Neoproterozoic Jinshuikou Group and occurs as stratiform-lenticular bodies. With estimated resources of 75 Mt and iron grades ranging from 15% to 28. 83%, the ore primarily consists of magnetite quartzite exhibiting typical banded struc tures. To gain a deeper understanding of the deposit genesis and provide a basis for regional mineral exploration, based on systematic field geological investigations combined with electron probe microanalysis (EPMA) of magne tite and whole-rock major and trace element geochemistry, this study systematically elucidates the geological charac teristics, ore-forming material sources, and genetic type of the deposit. EPMA results reveal that magnetite exhibits high TFeO content (90. 01%-92. 98%) and very low concentrations of TiO2 , MgO, MnO, CaO, and Al2 O3 (all < 0. 4%), consistent with the composition of magnetite from typical BIFs. Whole-rock geochemical data indicate variable w (TFeO) (15. 45%-74. 74%) and w (Al2 O3 ) (1.84%-17.04%) in the ore. The ore displays signifi cant positive Eu anomalies (Eu/ Eu∗ PAAS = 1. 38-2. 12), positive Y anomalies (Y/ Y∗ PAAS = 0. 98-1. 42), low Eu/ Sm ratio (0. 30-0. 51), and high Sm/ Yb (0. 69-2. 17) and Y/Ho (26. 55-40. 73) ratios. Collectively, these geochemical characteristics indicate that the ore-forming materials were primarily derived from seawater mixed with minor proportions (0. 1%) of high-temperature hydrothermal fluids. The absence of significant negative Ce anoma lies in the ore, combined with the attributes of the host rocks, suggests formation in a reducing marginal sea envi ronment. Integrating evidence from its strictly stratabound geological occurrence, typical magnetite quartzite mineral assemblage, and the characteristic geochemical signatures outlined above, this study identifies the Naxiguole iron deposit as a classic Superior-type BIF deposit.

 This study focuses on two fine-flake graphite metallogenic belts in the Shanxi Fault Uplift and South Qinling regions of Henan Province. Through field geological surveys, sample testing, and comprehensive analysis, the authors systematically investigated the distribution characteristics, enrichment regularity, and genetic mechanism of fine-flake graphite. Research indicates that fine-flake graphite ore bodies primarily occur in the Chishangou Formation of the Yinyugou Group within the Shanxi Fault Uplift and the Dagou Formation of the Douling Group in South Qinling, demonstrating significant stratigraphic specificity. Spatiotemporal distribution analysis reveals that the ore-hosting strata are mainly Paleoproterozoic, with deposits exhibiting a northwest-southeast trend, consistent with regional structural trends. The ore bodies are strictly strata-bound and conformable with the host strata. The ore-forming materials originate from a combination of organic and inorganic sources, with the deposit type classified as regional metamorphic. Further research demonstrates that the fine-flake characteristics of graphite are primarily influenced by tectonic stress, metamorphism and migmatization. These findings provide a scientific basis for a deeper understanding of the metallogenic patterns of fine-flake graphite deposits in Henan Province.

 Geochemical characteristics and potential evaluation of hydrocarbon source rocks are the core component of the petroleum system and play 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 Lishu Fault 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 measurement, rock pyrolysis, kerogen carbon isotope analysis, reflectance in oil testing, and gas chromatog raphy-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 ischaracterized by weak redox conditions, and the migration of the depositional center controls the distribution of high-quality hydrocarbon source rocks. In terms of organic geochemical characteristics, 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 hydrocarbon source rocks threshold (w(TOC)≥ 2. 0%). The kerogen is predominantly Type Ⅲ, followed by Type Ⅱ 2 , with a few samples exhibiting characteristics of TypeⅡ1 and TypeⅠ. Thermal maturity assessment indicates that the hydrocarbon 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 an enrichment in main hydrocarbon source rocks, 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.

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.

 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 exhibiting 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.

To address the limitation of existing suitability evaluation methods for underground space develop ment and utilization that predominantly rely on two-dimensional (2D) analyses and fail to accurately characterize three-dimensional (3D) underground space, the authors propose a multi-elements 3D suitability evaluation method based on a regular voxel model. By employing a voxel model as a unified evaluation framework, this study utilizes multiple 3D spatial analysis techniques to construct geological models and multi-factor 3D voxel attribute models of underground space. Combined with the analytic hierarchy process (AHP), an evaluation system incorporating con straint and graded indexes is constructed to evaluate the suitability of underground space development and utilization in the Zhengzhou High-Tech Zone. The results indicate that over 65% of the underground space in the study area is classified as highly suitable for development, with only a small proportion classified as restricted areas. Overall, the engineering geological and hydrogeological conditions are favorable for development and utilization. In terms of spa tial distribution, the shallow layer exhibits the highest suitability, with a slight decrease in suitable areas as depth increases. Horizontally, the western part of the study area shows greater development potential and suitability than the eastern part. Compared with traditional 2D evaluation methods, the multi-factors 3D suitability evaluation method for underground space development and utilization based on 3D voxel model enables organization, manage ment, computation, and visualization of evaluation results at any spatial location. It effectively addresses the loss of vertical information inherent in traditional 2D layered evaluation, enhances the evaluation resolution and result visi bility in the vertical dimension, and provides more comprehensive information and services for underground space planning and construction.

 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 curves (SWCC) of 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 the shear 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 linear 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.

 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-values. The results show  that the Mc for the Songliao Basin is 1. 4, indicating 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.

Water source quality safety is a major livelihood issue. With numerous water quality indicators and complex influencing factors, timely evaluation of water source quality is particularly important. Most current evaluation methods are relatively macro-level assessments based on existing quality standards, lacking relatively micro-level scien tific evaluation of water bodies in water source areas across different periods. Therefore, establishing a comprehensive evaluation system can provide a theoretical basis and technical support for pollution risk early warning in drinking water sources and for improving water environment quality. Based on the single-factor index evaluation method and the Nemero index method, the authors introduce the concept of an environmental capacity index to construct a multi-factor comprehensive environmental capacity index evaluation model and a Nemero method environmental capacity index model. These two models were used to conduct a comprehensive evaluation of a drinking water source in Dafeng District, Yancheng City, Jiangsu Province. Furthermore, based on the water quality evaluation, a health risk assessment was introduced to analyze the human health risks associated with the water source, comprehensively ensuring drinking water safety. The evaluation results indicate that the overall environmental quality of this water body shows a trend of improvement, while the chemical oxygen demand (COD) indicator shows a deteriorating trend; all other indicators show improving trends. Environmental quality in August was relatively poor within the year. The established multi-factor comprehensive environmental capacity index model and the Nemero method environmental capacity index model both can be used to evaluate water bodies in water source areas with stable categories. Among them, the improved Nemero method environmental capacity calculates the weight of each pollution factor, avoiding the neglect of certain pollutants with low concentration but high hazard. The total health risk of the water source area was around 1. 81 × 10-4 a-1-2. 30 ×10-4 a-1, classified as high risk. Carcinogenic arsenic contributed the most to this risk, followed by carcinogenic hexavalent chromium. Compared to non-carcinogenic risks, carcinogenic substances are the main source of potential risk through the drinking water pathway.