To clarify the subduction dynamic process of the Paleo-Pacific Plate, the residual effects of Mudanjiang Ocean closure, and the superposition relationship of regional tectonic domains, and to accurately reconstruct the Mesozoic tectonic evolution framework of the Northeast Asian continental margin, systematic studies including field geology, petrography, zircon U-Pb geochronology and whole-rock geochemistry were carried out on the newly identified Zhongxing Forest Farm granitoids of the Luobei Heilongjiang Complex. The research determined the formation age and petrogenesis of the granitoids, aiming to find out the emplacement age of the dykes and discuss their petrogenesis and geodynamic setting. The results show that the Zhongxing Forest Farm granitoids are biotite granodiorites, which occur as dykes intruding into the metaclastic rock matrix of Heilongjiang Complex in the field. Zircon LA-ICP-MS U-Pb dating results indicate that the Zhongxing Forest Farm granodiorites crystallized at (103 ±1) Ma, revealing that the Heilongjiang Complex had been emplaced between the Songliao Block and the Jiamusi Block prior to the Early Cretaceous. The Early Cretaceous granodiorites from the Zhongxing Forest Farm belong to the metaluminous calc-alkaline series, with w (Na2 O) > 3. 2%, A/ CNK < 0. 85, Ga/ Al < 2. 6 ×104, w (Zr) < 250 ×10-6 and no corundum in CIPW normative minerals, suggesting that they are I-type granites. The trace element ratios of the granodiorites are close to those of the lower crust, and their Zr-saturation temperatures fall into the category of high-temperature I-type granites. The granodiorites display a flat heavy rare earth element (HREE) distribution pattern, significant depletion in Ti and P, and a slight negative Eu anomaly, indicating that their magmas were derived from the mafic lower crust and experienced fractional crystallization of Ti-rich minerals, apatite, plagioclase and other minerals. Combined with the regional magmatic rock assemblages and tectonic characteristics, it is concluded that the formation of the Early Cretaceous granodiorites in the Zhongxing Forest Farm is closely related to the back-arc extension associated with the subduction of the Paleo-Pacific Plate.

 In order to systematically reveal the spatial distribution and enrichment patterns of the deep ore bodies in the Sanhe lead-zinc deposit in Genhe City, Inner Mongolia, and to guide the deep prospecting and prediction work in the mining area, the authors employed three-dimensional geological modeling technology and combined it with tectonic movements to conduct in-depth research on the largest and most valuable No. 1 ore body in the mining area. Through systematic collection and organization of geological data such as exploration reports, drilling data, cross-sectional diagrams, etc. In the mining area, a standardized geological database was constructed. At the same time, using the 3DMine mining software, a three-dimensional solid model and block model of the No. 1 ore body were established, and the grade and thickness attributes of Pb, Zn, and Ag in the block model were assigned using the distance power inverse ratio method, achieving the three-dimensional digital representation of mineralization information. Combined with the regional tectonic movement background, a comprehensive analysis was conducted on the controlling structures and mineralization enrichment patterns. The research results show that the morphology, occurrence, and enrichment degree of the No. 1 ore body are strictly controlled by the NWW direction ore-forming fault zone. The ore body can be divided into 3 distinct mineralization enrichment sections in the strike direction, and 4 mineralization enrichment sections in the dip direction. The mineralization enrichment areas were mainly developed in the NWW direction in the strike direction and the SW direction in the dip direction. The sections where the local tensile effect of the fracture zone is intense, especially those where the strike and dip directions of the tensile zone overlap, are the most favorable spaces for the accumulation and precipitation of ore-forming fluids, and are the core areas of mineralization enrichment. Based on the comprehensive three-dimensional model, the morphology of the ore body, the pattern of grade enrichment, and the analysis of tectonic control on mineralization, this study has identified four ore-forming target areas with significant exploration potential in the deep part of the No. 1 ore body. To clarify the priority order of exploration for the target areas, a semi-quantitative classification system based on the sufficiency of geological basis, the reliability of spatial inference, and the relevance of exploration engineering was established. It was divided into two categories: Ⅰ-level target areas and Ⅱ-level target areas. The Ⅰ-level target areas are given priority for drilling verification.

 Taking the Yu􀆳erya-Xiaoyingzi ore concentration area in Hebei Province as research object, the authors systematically analyze the mineralization regularity and prospecting direction of gold and polymetallic deposits combined with exploration results of typical deposits in the region based on 1 ∶ 50 000 water series sediment geochemical survey. The study area is located at the northern margin of North China Craton and controlled by Yanshanian tectonic-magmatic activities. The strata are mainly Archean Qianxi Group and Mesoproterozoic with well-developed fault structures, which provide both thermal sources and ore-hosting spaces for gold mineralization. Through the delineation and classification of geochemical anomaly, 34 anomalies were identified and categorized into class A, B, C, and D. Class A anomalies (e. g., Yu􀆳erya and Huajian gold deposits) have been confirmed as mineralized targets, while class B anomalies (e. g., Cuizhangzi and Qidaohe), though partially non-mineralized, show potential mineralization through their coupling with favorable geological settings. Geochemical studies of typical deposits (Yu􀆳erya, Huajian, and Changcheng gold deposits) reveal that Au and Ag serve as direct indicator elements, As, Sb and Hg indicate blind ores, Cu, Pb and Zn reflect polymetallic superposition, and Bi marks orebody tails. Gold anomaly zones exhibit NW-trending distribution, and controlled by NE- and NW-trending faults, with elemental association characteristics reflecting deposit scale and grade. Combined with regional geological setting, it is confirmed Archean metamorphic rocks as the primary source beds, with Yanshanian tectono-magmatic activities driving Au enrichment. Three prospecting targets (Cuizhangzi, Longxinzhuang, and Damaping) were selected based on their complex elemental associations (Au, Hg, Ag, etc. ), 3 + level concentration zonation, geological environments analogous to known deposits, and developed fault systems. This research reveals the coupling mechanism between metallogenic geological conditions and geochemical anomalies in the ore concentration area, and establishes geochemical prospecting criteria for magmatic-hydrothermal gold deposits .

 Aiming to reveal the activity patterns of volcanic eruption cycle in the 3rd Member of Yingcheng Formation (K1 y3) and to characterize basin filling during the final stage of rifting, and also provides scientific references for refined exploration of deep hydrocarbon resources. To achieve these objectives, the authors conducted a systematic study of the volcanic eruption cycle in the K1 y3 by utilizing methods such as field section observation, core analysis, thin-section identification, and geochemical analysis. Research indicates that three distinct volcanic eruption cycles are developed in the K1 y3 within the southeastern uplift of the Songliao Basin, and their stratigraphic succession is clearly defined. The lower cycle (C-I) consists mainly of acidic pyroclastic rocks interlayered rhyo lite, the middle cycle (C-II) is dominated by intermediate-basic lava with interbedded pyroclastic, and the upper cycle (C-III) is composed of acidic lava with associated pyroclastic units. Geochemically, C-I and C-III exhibit similar characteristics; they are Si- and K-rich and belong to the potassic to high-K calc-alkaline series. Both cycles display pronounced LREE/ HREE fractionation, marked negative Eu anomalies, strong enrichment in Pb as well as other large-ion lithophile elements (e. g., Rb, K), and notable depletion in Ti, Ce, Eu, Sr, and P, along with other HFSE. In contrast, C-II is characterized by Na-rich and high-Al, and belongs to the sodic alkaline calc-alkaline series. It shows high total REE and pronounced LREE-HREE fractionation but lacks a significant Eu anomaly. The cycle is enriched in Ba, K, and Pb, while displaying strong depletion in Ti and notable deficits in Th, Nb, Ta, and other HFSE. These characteristics suggest that the K1 y3 volcanic rocks were generated in an intraplate continental rift setting influenced by subduction of the Pacific Plate beneath the Eurasian margin. The magmas of C-I and C-III were likely derived from the partial melting of the lower crust, whereas C-II was originated from a depleted mantle source and underwent significant fractional crystallization. The three cycles show distinct geochemical signatures and lack continuous evolutionary relationships. C-I records early episodic acidic eruptions accompanied by reworked volcanic deposits. C-II reflects large-scale and relatively steady eruptions of intermediate-basic lava. C-III represents extensive acidic volcanism during the waning stage of lower crustal melting and heat supply.

The tight sandstone reservoirs of Shuixigou Group in Shengbei Sag of Taibei Depression, Turpan Hami Basin, represent a key target interval for hydrocarbon exploration in the basin, where overpressure is extensively developed. To systematically analyze the genetic mechanisms of overpressure in this interval, the authors compre hensively employed multiple methodologies, including comprehensive logging curve analysis, acoustic velocity density cross-plot analysis, porosity contrast method, pressure calculation inversion method, and fluid inclusion paleopressure reconstruction method. The results indicate that overpressure is predominantly distributed within the depth range of 2 000-5 500 m in Shengbei Sag, with a pressure coefficient ranging from 1. 2 to 1. 5, and two primary genetic types of overpressure have been identified, namely undercompaction-induced overpressure caused by rapid sedimentation and mudstone sealing and hydrocarbon generation-induced overpressure generated by hydrocarbon generation and expulsion processes; combined with the geological data of the study area, comprehensive logging curves analysis and porosity contrast method are determined to be the most suitable approaches for investigating overpressure genesis herein, where the former identifies overpressured intervals by characterizing the response features of logging curves such as acoustic transit time and resistivity curves, while the latter infers the presence of pressure sealing and further inverts the intensity and distribution range of overpressure by comparing the deviation of measured porosity from the theoretical compaction trend. Furthermore, the effects of overpressure on reservoir quality were investigated using techniques such as casting thin section observation, physical property testing, and microscopic characterization of fluid inclusions, and the results demonstrate that hydrocarbon generation-induced overpressure exerts a significant constructive effect on the reservoirs, on the one hand, this type of overpressure can induce the development of microfracture systems in rocks, which effectively improves the permeability of tight sandstones and provides preferential pathways for hydrocarbon migration; on the other hand, organic acids released during hydrocarbon generation can dissolve reservoir minerals such as feldspar, forming abundant intragranular dissolved pores and thus optimizing the reservoir space, while the primary pores preserved by undercompaction also constitute one of the critical factors for the formation of abnormally high-porosity zones.

To clarify the pore structure characteristics, pore heterogeneity, and to reveal the main controlling factors of fractal characteristics of the tight shale reservoirs of Qingshankou Formation in northern Songliao Basin. The authors took the tight shale reservoirs of Qingshankou Formation in northern Songliao Basin as the research object, a variety of analytical methods including X-ray diffraction (XRD), total organic carbon (TOC) test, nitrogen adsorption-desorption experiment, and mercury intrusion porosimetry were used to systematically analyze the pore structure, organic carbon content, and pore structure parameters of shale samples. Fractal theory was adopted to calculate the fractal dimensions of different pore size intervals (micropores, mesopores, macropores, and macro-macropores) as well as the comprehensive fractal dimension (Ds), and the correlation between pore fractal characteristics and mineral composition, w (TOC), specific surface area, and average pore size was thoroughly explored. The results show that the mineral composition of shale samples in the study area is dominated by clay min erals and felsic minerals, and the reservoir space is mainly intergranular pores of clay minerals. The pores are charac terized by good sorting and fine skewness, with micropores and mesopores (pore size < 50 nm) as the dominant types, while only a small amount of macro-macropores are developed. The fractal dimension of micropores ranges from 2. 47 to 2. 88 with an average of 2. 71; that of mesopores ranges from 2. 41 to 2. 53 with an average of 2. 46; that of macropores ranges from 2. 07 to 2. 88 with an average of 2. 26; and that of macro-macropores ranges from 2. 46 to 3. 08 with an average of 2. 75. The comprehensive fractal dimension (Ds) varies from 2. 41 to 2. 55 with an average of 2. 47. In general, the pores of shale samples in study area are relatively complex with strong heterogeneity. Moreover, the fractal dimension has different degrees of correlation with clay mineral content, w (TOC), specific surface area, and average pore size, among which the correlation with the fractal dimension of mesopores is the highest. This indicates that mesopores are the main contributor to the reservoir space of shale samples in study area.

To finely characterize the reservoir structure of unconfined slope channels in gravity flow deposits of Baiyun Sag, Pearl River Mouth Basin, the authors took the X Gas Field in Baiyun Sag as the research object. Comprehensive use was made of core, logging, seismic inversion and other data to study the internal structure and quantitative characteristics of unconfined channel reservoirs at different levels. A fine characterization method for the internal structure of unconfined channels was established, and the contacted and connected relationship of channel sandbodies were revealed. The research results show that: ① The study area mainly develops medium-fine-grained feldspathic quartz sandstone. Core grain size data points are basically parallel to the C = M baseline, with massive mud gravels and intense bioturbation without obvious incised bedforms, indicating an unconfined channel system. ② The channel system in the study area develops four composite channel sequences, multiple composite channels and isolated channels. The width of composite channel sequences is on the kilometer scale, with an aspect ratio of 133-136. The width of composite channels is approximately 1 000 m, with an aspect ratio of 10-55. The scale of solated channels is difficult to determine, with a width of about 50-100 m and an aspect ratio of 4-8. ③There are four superposition modes of sandbodies inside the unconfined channels, including vertical isolated, channel-channel lateral superimposed, channel-channel lateral juxtaposed, and isolated channels. Among them, the incised-superimposed reservoir structure has the best connectivity, the juxtaposed reservoir structure has good connectivity, and the isolated reservoir structure is disconnected. This research achievement can be used to guide the precise development and development adjustment of oil and gas fields in unconfined gravity flow channels.

 To further elucidate the microscopic mechanism by which supercritical carbon dioxide (SCCO2 ) alleviates water-lock in tight sandstones, the authors selected tight sandstones from the Shahezi Formation in Lishu Fault Depression of Songliao Basin as the study object and systematically investigated the changes in pore structure and water occurrence state of the reservoir during water saturation, water-locking formation, conventional N2 flooding, and SCCO2 miscible treatment. The experiments comprised vacuum water saturation and high-pressure water-retention water-lock simulation, N2 flooding under different pressure differentials, water-SCCO2 miscible treatment followed by N2 gas flooding, and together with nuclear magnetic resonance (NMR) T2 spectrum inversion, pore size distribution analysis, and cast thin-section observations, quantitatively characterized the stage-by-stage variations in porosity, pore throat scale, and movable water proportion. Water saturation experiments indicate that the initial water saturation of the tight sandstone is lower than the bound-water saturation, and the water-phase invasion process can be divided into three stages: 1 min to 5 min is a rapid saturation stage, during which a large amount of water rapidly occupies micro-nano pores; 5 min to 5 h is a slow invasion stage with continuously increasing water content; after 5 h, the system becomes essentially stable, suggesting a short formation time and strong stability of the water-locking. Conventional N2 flooding exhibits pronounced pore-size selectivity: when the pressure differential reaches 3 MPa, water in large pores ( >300 nm) is displaced first; when the pressure differential increases to 4-6 MPa, water in 80-300 nm pores is only partially removed, whereas water in finer pores remains difficult to displace, and the overall flooding efficiency remains below ~30%. SCCO2 miscible treatment markedly alters the pore-throat structure of the cores: the low viscosity and high diffusivity of SCCO2 enable it to enter dominant flow pathways and react with carbonate cements in pores via acid dissolution, resulting in a 40%-80% increase in porosity, an enlarged mean pore-throat radius, and enhanced pore connectivity. The results demonstrate that, after SCCO2 treatment, the sand stone pore system becomes more open and the degree of water-phase confinement decreases; compared with conven tional N2 flooding, the miscible-treatment-gas-flooding combination is more favorable for alleviating water-locking in micro-nano pores, and this coupled workflow shows clear advantages in improving pore structure and enhancing flooding efficiency in tight sandstones.

 Based on the petrophysical characteristics of volcanic rocks of the Guantao Formation in Shaxibei Structural Belt, the authors primarily classify them into two major types ( basalt and tuff) with significant differences in their petrophysical parameters. Basalt exhibits high-velocity and high-density characteristics, partially overlapping with sandstone in certain areas, whereas tuff is indistinguishable from sandy mudstone in terms of both velocity and density. To address the identification challenges caused by the overlap of petrophysical parameters among volcanic rocks, the authors propose a frequency division inversion method based on split phase reconstruction combined with seismic inversion technology, which can accurately identify volcanic rocks with multi-level and multi parameter. The approach first utilizes the high-velocity and high-density characteristics of basalt, preferentially selecting the 90° phase component of seismic data for phase-reconstruction based inversion to amplify subtle impedance variations and clearly delineate basalt boundaries. Subsequently, by integrating the low gamma-ray response characteristic of volcanic rocks, the reconstructed seismic data combining 0° and 90° phases are used as training samples to conduct nonlinear frequency-division inversion, thereby effectively enhancing the overall identification accuracy of volcanic rocks. This technique enhances the inversion technology of volcanic rocks, overcomes the limitations of insufficient accuracy in single-parameter inversion and the poor representativeness of samples in nonlinear inversion, achieving precise multi-parameter and multi-level characterization of volcanic rocks. Practical application shows that through refined delineation of volcanic rock boundaries, multiple structural-lithological traps have been newly identified in Shaxibei structural belt. Based on these findings, an exploration well targeting a new sequence was deployed and successfully encountered oil-bearing zones, not only validating the effectiveness of the traps but also significantly improving exploration efficiency in this volcanic-rich zone, and providing effective decision making scheme for well location design, well location optimization and reservoir discovery.

 To investigate the spatiotemporal changes in carbon storage within the Heilongjiang watershed and simulate future carbon storage under different scenarios, the authors compare three cellular automata models in study area. The patch generating land use simulation (PLUS) model, integrated with the integrated valuation of ecosystem services and trade-offs (InVEST) model, was selected and applied to simulate future land use and land cover (LULC) and carbon storage dynamics in the Heilongjiang watershed. The results of large-scale transnational LULC evolution and carbon storage change indicate that: ① The PLUS model demonstrated high accuracy for large scale transnational LULC simulation in the Heilongjiang watershed (OA = 0. 897 2, Kappa = 0. 842 6). ② From 2000 to 2020, land cover changes in the basin were primarily characterized by conversions among forest land, cropland, and grassland, while artificial surfaces expanded rapidly, encroaching on cropland area. Temperature and precipitation were important driving factors for the expansion of forest land, grassland, and cropland, and cropland expansion was also strongly related to GDP. ③ The coupled PLUS-InVEST model enabled the analysis and prediction of carbon storage changes in the Heilongjiang watershed. From 2000 to 2020, carbon storage within the basin initially decreased and then increased, with an overall reduction of 3. 171 × 107 t. Specifically, carbon storage decreased by 1. 930 × 107 t in Chinese portion, 0. 090 × 107 t in Russian portion, and 0. 017 × 107 t in Mongolian portion. Scenario-based projections of LULC and carbon storage for 2030 shows that the ecological protection priority scenario yielded the highest carbon storage, reaching 619. 350 ×107 t. Within this total, Chinese portion increased 0. 530 × 107 t, reaching 325. 110 × 107 t, Russian portion increased 0. 010 × 107 t, reaching 249. 250 ×107 t, while Mongolian portion decreased 0. 180 ×107 t, reaching 44. 990 ×107 t. The study highlights the importance of both human activities and the natural environment in achieving carbon neutrality and suggests that ecological protection measures should be implemented to enhance regional carbon storage levels.

 In order to ensure the stability of the foundation pit and prevent geological disasters such as ground collapse and landslides, it is crucial to implement long-term and continuous deformation monitoring. The Leica TS60 measurement robot, as a high-precision monitoring device, is widely used in various deformation monitoring tasks and can achieve automated, high-frequency data collection. However, during practical application, the device  still has certain limitations, primarily reflected in poor real-time data transmission, inability to perform real-time data processing and analysis, etc. To address the aforementioned engineering application issues, a comprehensive and intelligent deformation monitoring system was developed by leveraging the (geodetic communication, GeoCOM) development interface provided by the Leica TS60, combined with mobile internet and cloud computing technologies. This system establishes communication connections with the TS60 measurement robot using Android Bluetooth communication technology, enabling wireless control and real-time data acquisition of the TS60. Data collection and error calculations are performed via a mobile APP, while qualified data is saved in JSON format and uploaded to a cloud server for storage and management in a MySQL database. On the Web-side software, functions such as deformation quantity calculation, deformation error statistics, GM (1, 1) model-based deformation trend analysis, deformation prediction and warning, and automatic generation of monitoring daily reports are implemented. Application testing results demonstrate that the system can achieve high-precision data collection and automated processing of deforma tion data, reducing manual intervention and improving deformation monitoring efficiency. Additionally, the defor mation prediction results generated by the system align with those from the professional statistical analysis software SPSSpro, confirming the reliability of its analysis and prediction module.

 Accurate detection of goaf is the core link to ensure mine safety and ecological environment restoration. In view of the serious multi-solution of single geophysical method, there are problems of insufficient resolution and  large depth error in goaf identification, the authors propose a cross-gradient joint inversion method with normalization operator. Comprehensive utilization of three kinds of geophysical data advantage information (gravity, seismic and transient electromagnetic method), the interference of dimensional differences of different physical parameters on structural coupling is overcome by embedding a normalization operator in the cross-gradient function. Lagrange multiplier method is used to transform the structural constraints into optimization problems, and the simultaneous inversion of multiple physical parameters is realized. The model test shows that the accuracy of the joint inversion results is significantly improved in the deep adjacent small-scale goaf model. The accuracy is calculated by the relative difference between the inversion results and the real physical property distribution, and the accuracy of gravity data is improved by 50. 53%, the accuracy of electrical data improved by 21. 22%, the accuracy of seismic data improved by 13. 65%, respectively. False anomaly is effectively suppressed, and the boundary of the goaf is more clearly depicted. Noise resistance tests demonstrate that, the location and extent of the goaf are still reliably identified by the joint inversion under 10% random noise, false anomalies appear only in the surrounding rock that lacks any abnormal physical properties, indicating good stability and practical utility of the proposed method. Method is applied to the measured data of coal mine goaf. The horizontal position (2 150-2 520 m) and depth range (40-80 m) of the goaf given by the joint inversion are highly consistent with the known geological data, which verifies the reliability and engineering practicability of the method. Study results show that the method can significantly improve both the accuracy and the resolution of goaf detection, offering a new technical tool for the safe monitoring and management of coal mine goaf.

To achieve the sustainable utilization of geothermal resources, avoid thermal breakthrough caused by low-temperature reinjection water, and ensure its long-term stable exploitation, the authors systematically evaluate the total reserves and exploitable potential of geothermal resources in Tonghe County, Heilongjiang rely on comprehensive geological exploration and well-logging data using the heat storage method. On this basis, a three-dimensional numerical model was constructed on the COMSOL Multiphysics platform, incorporating stratigraphic structure, hydrothermal coupling mechanisms, and reinjection boundary conditions. The model dimensions are 1 600 m × 1 200 m ×500 m,with a burial depth of approximately 1 400 m, and the central aquifer-type reservoir has a thickness of 174 m. An exploitation mode of “one injection-one production” was adopted, combined with a cyclic injection production operation scheme, in which reinjection and production wells operated at equal flow rates. The evolution regularity of the reservoir temperature field under different combinations of production and reinjection rate and well spacing was comprehensively analyzed. The migration path of the cold-water front and its impact on production well temperature were examined, with a temperature drop of 2 ℃ at the production well defined as the criterion for ther mal breakthrough, thereby determining reasonable parameters for well spacing and production and reinjection rate. The results show that the total geothermal heat storage in Tonghe County is approximately 2. 07 × 1018 J, with exploitable resources equivalent to 2. 17 ×107 t of standard coal, indicating significant development potential. The simulations further reveal that the cold front generated by reinjection of low-temperature reinjection water progres sively advances toward the production well over operation time. Excessively small well spacing or overly high production and reinjection rate aggravates thermal interference and induces premature thermal breakthrough, there by reducing system service life and heat exchange stability. To ensure 100 years of continuous operation without thermal break-through, the minimum safe well spacing must be strictly matched with the production and reinjection rate. Specifically, when the rate is 30 m3 / h, the well spacing must exceed 300 m, and for rates of 40, 60, 80, 100, and 120 m3 /h, the required well spacing should increase correspondingly to 350, 400, 450, 500, and 550 m, respectively.