In a region where lizard fossils are rare, this study explores a groundbreaking discovery of squamate lizard materials from the upper part of Nenjiang Formation (early Campanian) in Jilin Province, Northeast China. Despite the fragmentary nature of the dentaries, they exhibit distinct tooth morphological characteristics of squamate lizards, suggesting insectivorous and omnivorous diets for these small reptiles. This finding not only represents a significant addition to the squamate lizard fossil records from the Late Cretaceous in Northeast China but also contributes to our understanding of the paleogeographic distribution of squamate lizards. Furthermore, it sheds new light on the terrestrial vertebrate fauna of the Cretaceous Songliao Basin.

 Based on drill core and thin section observation, major geochemical element analysis and conventional well log analysis, this study summarizes the characteristics and thickness of weathering crust of Pennsylvanian volcanic rocks (Carboniferous) in Shixi area, Junggar Basin. The weathering crust is identified and divided into three types according to the petrological characteristics and well log interpretations in Shixi area, and the isopach of weathering crust is mapped. The results show that: (1) With the increase of depth, the weathering weakens, and the rocks become less fractured with decreased porosity; (2) the weathering crust of the Upper Carboniferous volcanic rocks can be divided into strongly weathered and mildly weathered layers in Shixi area; (3) the weathering crust is relatively thicker in Dinan uplift and Shixi uplift. This study provides research basis for further evaluation of Upper Carboniferous volcanic reservoir, and will benefit for well location deployment and potential oilfield development in the Shixi area.

  Highly evolved granite is an important sign of the mature continent crust and closely associated with deposits of rare metals. In this work, the authors undertake systematically zircon U-Pb ages and whole rock elemental data for highly evolved granitic intrusions from the Great Xing’an Range (GXR), NE China, to elucidate their discriminant criteria, spatial-temporal distribution, di?erentiation and geodynamic mechanism. Geochemical data of these highly evolved granites suggest that high w(SiO2) (>70%) and di?erentiation index (DI>88) could be quanti?ed indicators, while strong Eu depletion, high TE1,3, low ΣREE and low Zr/ Hf, Nb/Ta, K/Rb could only be qualitative indicators. Zircon U-Pb ages suggest that the highly evolved granites in the GXR were mainly formed in Late Mesozoic, which can be divided into two major stages: Late Jurassic–early Early Cretaceous (162–136 Ma, peak at 138 Ma), and late Early Cretaceous (136–106 Ma, peak at 126 Ma). The highly evolved granites are mainly distributed in the central-southern GXR, and display a weakly trend of getting younger from northwest to southeast, meanwhile indicating the metallogenic potential of rare metals within the central GXR. The spatial-temporal distribution, combined with regional geological data, indicates the highly evolved Mesozoic granites in the GXR were emplaced in an extensional environment, of which the Late Jurassic–early Early Cretaceous extension was related to the closure of the Mongol– Okhotsk Ocean and roll-back of the Paleo-Paci?c Plate, while the late Early Cretaceous extension was mainly related to the roll-back of the Paleo-Paci?c Plate. 

 The Erguna ductile shear zone is situated in the Erguna Massif, which has been exposed along the eastern bank of the Erguna River in northeastern China. The authors present comprehensive study results on the macro- and micro-structures, ffnite strain and kinematic vorticity, quartz electron backscatter diffraction (EBSD) fabrics, and geochronology of granitic rocks in the Erguna ductile shear zone. The deformed granitic rocks have experienced significant SE-trending dextral strike-slip shearing. Finite strain and kinematic vorticity in all deformed granitic rocks indicate that the deformation is characterized by simple sheardominated general shearing with S-L tectonites. Mineral deformation behaviors and quartz C-axis textures demonstrate that the deformed granitic rocks developed under greenschist to amphibolite facies conditions at deformation temperatures ranging from 450 to 550 ℃. New LA-ICP-MS zircon U-Pb ages indicate that these granitic rocks were formed in Early Triassic (~248.6 Ma) and Early Cretaceous (~136.7 Ma). All the evidence indicates that this deformation may have occurred in Early Cretaceous and was related to the compression resulting from the ffnal closure of the Mongol-Okhotsk Ocean. 

 The Longgang Block is one of the most important parts of the eastern North China Craton, characterized by extensive Late Neoarchean (~2.5 Ga) granulite facies metamorphism. However, it remains uncertain whether it was inffuenced by Paleoproterozoic magmatism-metamorphism. The authors provide a comprehensive analysis of amphibolite in Laojinchang area, southern Jilin Province, through petrographic, geochemical, mineralogical, and zircon dating. The main ffndings are as follows: The mineral assemblage of amphibolite is Hb+Pl+Cpx+Bi+Kf+Q, characteristic of amphibolite facies; zircon U-Pb dating indicates that the metamorphic age of amphibolite is 1 834±33 Ma; the amphibolite has geochemical characteristics of calcium alkaline, with depletion of Nb, Ta, Ti and P. The plagioclase in the amphibolite is oligoclase, belonging to acidic plagioclase. It is speculated that the protolith of the amphibolite is diorite; using geothermobarometer, the peak metamorphic P-T conditions of amphibolite are determined to be 536–593 ℃/ 3.4–5.0 kbar, and the post-peak conditions are 429–566 ℃/1.3–3.1 kbar. The above results indicate that the Paleoproterozoic metamorphism has been superimposed on Longgang Block, linked to a new orogenic event on the northern edge of North China Craton. 

 Volcanic oil and gas reservoirs are generally buried deep, which leads to a high whole-well coring cost, and the degree of development and size of reservoirs are controlled by volcanic facies. Therefore, accurately identifying volcanic facies by logging curves not only provides the basis of volcanic reservoir prediction but also saves costs during exploration. The Songliao Basin is a ‘fault-depression superimposed’ composite basin with a typical binary filling structure. Abundant types of volcanic lithologies and facies are present in the Lishu fault depression. Volcanic activity is frequent during the sedimentary period of the Huoshiling Formation. Through systematic petrographic identiffcation of the key exploratory well (SN165C) of the Lishu fault-depression, which is a whole-well core, it is found that the Huoshiling Formation in SN165C contains four facies and six subfacies, including the volcanic conduit facies (crypto explosive breccia subfacies), explosive facies (pyroclastic flow and thermal wave base subfacies), effusive facies (upper and lower subfacies), and volcanogenic sedimentary facies (pyroclastic sedimentary subfacies). Combining core, thin section, and logging data, the authors established identification markers and petrographic chart logging phases, and also interpreted the longitudinal variation in volcanic petro-graphic response characteristics to make the charts more applicable to this area＇s volcanic petrographic interpretation of the Huoshiling Formation. These charts can provide a basis for the further exploration and development of volcanic oil and gas in this area. 

  The reffnement of the 1cm geoid holds signiffcant importance in engineering applications, where the accuracy of the geoid is frequently constrained by its resolution. However, there has been limited exploration into the speciffc relationship between geoid resolution and accuracy. This article aims to address this gap by thoroughly examining said relationship. This study employs the CapRCR modification to calculate the geoid of Gongzhuling City. The ffndings indicate that the accuracy can be enhanced by 2% to 9% through encryption of the geoid resolution from 2.5′×2.5′ to 1.5′×1.5′. Furthermore, this improvement can be augmented by 15% to 21% through encryption of the gravity anomaly to the same resolution. The accuracy of the geoid exhibits a linear relationship with the resolution of gravity anomalies. The theoretical accuracy of the geoid, excluding integration errors, is determined to be 1.21 cm. In engineering applications, opting for a resolution of 30''×30'' can result in the geoid containing only an integration error of 2 mm. However, to attain an accuracy of 1 cm, it becomes imperative to further mitigate data errors. Consequently, the ffnal reffned quasi-geoid accuracy is established at 0.56 mm. 

  The naming of rock hand specimens is usually conducted by geological workers based on observed mineral composition, texture characteristics, etc., combined with their own knowledge reserves. The accuracy of identiffcation results is limited by the experience, research interests, and identiffcation level of the identiffer, as well as the complexity of the rock composition. To improve the efffciency of rock hand specimen identification, this paper proposes a method for rock image recognition and classification based on deep learning and the Inception-v3 model. It encompasses the preprocessing of collected photographs of typical intrusive rock hand specimens, along with augmenting the sample size through data augmentation methods, culminating in a comprehensive dataset comprising 12501 samples. Experimental results show that the model has good learning ability when there is sufffcient data. Through iterative training of the Inception-v3 model on the rock dataset, the accuracy of rock image recognition reaches 92.83%, with a loss of only 0.2156. Currently, several common types of intrusive rocks can be identified: gabbro, granite, diorite, peridotite, granodiorite, diabase, and granite porphyry. Software is developed for open use by geological workers to improve work efffciency. 

 Transient Rayleigh wave detection is a high-precision nondestructive detection method. At present, it has been widely used in shallow exploration, but rarely used in tunnel lining quality detection. Through the tunnel lining physical model experiment, the layout defects of the double-layer reinforcement lining area were detected and the Rayleigh wave velocity pro?le and dispersion curve were analyzed after data processing, which ?nally veri?ed the feasibility and accuracy of Rayleigh wave method in detecting the tunnel lining void area. The results show that the method is not a?ected by the reinforcement inside the lining, the shallow detection is less disturbed and the accuracy is higher, and the data will ?uctuate slightly with the deepening of the detection depth. At the same time, this method responds quite accurately to the thickness of the concrete, allowing for the assessment of the tunnel lining’s lack of compactness. This method has high e?ciency, good reliability, and simple data processing, and is suitable for nondestructive detection of internal defects of tunnel lining structure. 

 There are a large number of Mesozoic intrusive and volcanic rocks in western Liaoning of China, which is an ideal place to study the Mesozoic Paleo-Paci?c subduction processes, and lithospheric destruction of North China Craton. Detailed petrographic, zircon U-Pb dating and geochemical studies of the Early Jurassic granites in Huashan pluton, Xingcheng, western Liaoning, indicate that the Early Jurassic granites were formed at 184–174 Ma, mainly composed of syenite and monzogranite. The geochemical characteristics show high contents of SiO2, Al2O3 and Na2O+K2O, low contents of Fe2O3 and MgO, enrichment in LREEs and LILEs, and depletion in HREEs and HFSEs, and have a high content of Sr and low contents of Y and Yb, with weak negative Eu anomalies and slightly negative anomalies of Ce, indicating that they are a set of intermediate-acidic adakitic granites in high-K calc-alkaline series. All the facts signi?cantly suggest that the Early Jurassic adakitic granites were formed at the active continental margin in the context of Paleo-Paci?c plate subduction. 

 The basin marginal fault system is the key to understand the formation and evolution of Songliao Basin. In order to investigate the inffuence of marginal fault system on the structural evolution of Songliao Basin, a comprehensive study was conducted on Shiling Town and Zhuanshanhu area of Yehe Town in Siping City of Jilin Province, where is the southeastern margin of the Songliao Basin and there are a series of well-exposed fault, fold and intrusive bodies belonging to the main marginal fault system of the Songliao Basin known as the Jiamusi-Yitong (Jia-Yi) fault zone. Through proffle measurement and ffeld investigation, samples with various lithologies and distinctive features were collected. Detailed ffeld and laboratory works include component and microstructure analysis of these samples, rock-rock contact analysis, main strike measurement and statistics analysis. These data reveal the structural characteristics of the fold, fault and intrusive bodies in the study area. The research results show that the folds are distributed in the Mesozoic strata near the main fault of the eastern branch of the Jia-Yi fault zone, and the folded strata involve the Cretaceous Denglouku and Quantou formations. In addition, the section is dominated by high-angle strikeslip thrust faults. Light-colored veins and dark-colored veins are extensively distributed in the exposed granites. Statistical analysis of joint and fault attitudes in the study area reveals a right-lateral strike-sliping along the main fault. The large-scale right-lateral strike-slip and thrust fault system in Shiling Town occurred in right-lateral transpressive stage in Late Cretaceous. Based on the results above, tectonic evolution sequence in Shiling section of the Jia-Yi fault zone during the Mesozoic can be divided into ffve stages: Middle Jurassic left-lateral ductile strike-slip stage, Late Jurassic compression stage, Early Cretaceous tension stage, Early Cretaceous extension stage and Late Cretaceous right-lateral transpressive stage. These may have important constraint on understanding the Mesozoic evolution of the Songliao Basin. 

 The Beishan pluton in Gansu of China was selected as the simulated model. The simulation results indicate that the formation of unloading joints in granite is mainly in?uenced by the unloading rate of con?ning pressure. Among the rates tested, the slowest unloading rate 0.025 MPa/s is found to be most conducive to the development of unloading joints. Therefore, a slower unloading rate is favourable for the occurrence of unloading joints. A series of simulations with varying initial depths of uplift ranging from 900 m to 200 m were conducted. The results con?rm that when the specimen rises to a depth of 550–500 m, the unloading joints begin to form. The uplift from a depth of 700–500 m, with variations in both vertical and lateral unloading rates, was simulated. The generation of unloading joints exhibits a negative correlation with vertical unloading and no correlation with lateral unloading, indicating that the unloading joints are mainly controlled by the unloading of vertical pressure. Throughout the simulation process, the vertical joints exhibit irregular and unrealistic regularity, suggesting a more complex formation mechanism than that of the unloading joints. 

 The superparamagnetic effect arises from the superparamagnetism exhibited by a multitude of nano-sized magnetic mineral particles under an external electric ffeld. This phenomenon manifests in transient electromagnetic data primarily as a deceleration in the attenuation rate of late-stage signals, a characteristic difffcult to discern directly from airborne transient electromagnetic signals, consequently leading to signiffcant misinterpretations of subterranean electrical structures. This study embarks on 3D forward modeling of airborne electromagnetic responses in the frequency domain, accounting for the superparamagnetic effect, utilizing an unstructured finite element method. Superparamagnetic responses in the time domain were obtained through frequency-time conversion. This investigation explores the influence of various parameters—such as magnetic susceptibility, time constants, and ffight altitude—on the superparamagnetic effect by examining the response characteristics of typical targets. Findings indicate that in its late stages, the superparamagnetic effect can induce a relative anomaly of up to 300%. There is a positive correlation between magnetic susceptibility and the strength of the superparamagnetic effect. The inffuence of the time constant's upper and lower limits on the superparamagnetic effect is minimal; however, the range between these limits significantly affects the effect, showing a negative correlation with its intensity. Higher flight altitudes weaken the superparamagnetic signal. The impact is most pronounced when superparamagnetic minerals are shallowly buried, effectively shielding the underlying geology with the characteristics of a good conductivity anomaly, but this effect diminishes with greater depth. The insights from this study provide a theoretical framework for a deeper understanding of the superparamagnetic effect in transient electromagnetic signals and for more accurate interpretations of subterranean geological and electrical structures. 

 The Daerlong granitic complex in Linkou area is located at the convergence position of the Jiamusi and Songliao blocks. A systematic study of field geology, petrography, zircon U-Pb dating and wholerock major and trace elements has been conducted for the Daerlong granitic complex, aiming to determine its formation age, petrogenesis and tectonic setting, and further constrain the nature and evolution of the Mudanjiang Ocean. Field and petrographic observations show that the Daerlong granitic complex mainly consists of three rock types from old to young, i.e., biotite granodiorite, syenogranite and monzogranite. Geochemical data suggest that all the types of granitoids are high in silicon, rich in potassium, moderate in aluminum (A/CNK=0.94–1.10), poor in iron and magnesium, rich in LILEs and depleted in HFSEs, belonging to the weakly peraluminous high-K calc-alkaline series. Combined with mineral assemblages and geochemical discrimination diagrams, it can be determined that the studied granitoids are of igneous crustderived I-type origin, which underwent strong fractional crystallization and crystal accumulation during magmatic evolution. Zircon LA-ICP-MS U-Pb dating results show that the different types of granitoids were emplaced in a wide age range from 301 to 240 Ma, indicating a long-lived Late Carboniferous to Middle Triassic granitic magmatism occurred in the western Jiamusi Block. The Daerlong granitoids have similar geochemical characteristics of subduction-related igneous rocks. Considering the spatial and temporal distribution of Late Paleozoic to Early Mesozoic igneous rocks within eastern Heilongjiang Province, it is concluded that the Daerlong granitic complex was formed in an active continental margin setting rather than a continental rift environment. The results suggest that the Mudanjiang Ocean might not be a limited ocean evolved from the rifting of the uniffed Jiamusi-Songnen microcontinent. 

 A single-layer monument Svobodny, ancient man＇s parking lot-1, discovered in 2021 as part of archaeological work to study the zone of economic development of the Amur region was investigated lithologically and palynologically. Based on the results of geomorphological analysis of the territory, the study of artifacts, palynological data, as well as analogy with previously identiffed and sufffciently studied relics in the region, the existence of the Osinoozersk late Neolithic culture in this territory is assumed. The time of its expansion in the Amur region is determined within the framework of the second half of the IV millennium BC to the ffrst half of the II millennium BC. The preliminary results of palynological analysis suggest the existence of a temperate climate here, was close to the modern one, which does not contradict the reconstructed paleoclimate and environments of the region during the Holocene period. 

 The authors proposed a symplectic stereo-modeling method (SSM) in the Birkhoffian dynamics and apply it to the visco-acoustic least-squares reverse time migration (LSRTM). The SSM adopts stereo-modeling operator in space and symplectic Runge-Kutta scheme in time, resulting in great ability in suppressing numerical dispersion and long-time computing. These advantages are further confirmed by numerical dispersion analysis, long-time computation test and computational efficiency comparison. After these theoretical analyses and experiments, acoustic and visco-acoustic LSRTM are tested and compared between SSM method and the conventional symplectic method (CSM) using the fault and marmousi models. Meanwhile, dynamic source encoding and exponential decay moving average gradients method are adopted to reduce the computation cost and improve the convergence rate. The imaging results show that LSRTM based on visco-acoustic wave equations effectively takes into account the influence of viscosity can therefore compensate for the amplitude attenuation. Besides, SSM method not only has high numerical accuracy and computational efficiency, but also performs effectively in LSRTM.

 In order to understand the geochemical characteristics of Paleozoic reservoir fluids in Xuanjing region, Lower Yangtze area, drilling core samples from Y and D wells were tested and analyzed to study the fluid inclusion types and composition. Pressure correction was undertaken to determine the temperature and pressure environment for inclusion formation, and the influence of fluid characteristics of the Upper Permian and Lower Triassic reservoirs on the preservation of shale gas was investigated. According to petrographic observations, fluid inclusions are mainly brine and bitumen inclusions. Bitumen inclusions are mainly distributed in holes and fractures, and with smaller individuals. No visible fluorescence was observed, and the vitrinite reflectance is 3.39%–3.92%. This indicates that there had been oil and gas accumulation in the early stage of diagenesis in the study area, but due to the influence of magmatic hydrothermal solution, oil and gas underwent thermal metamorphism in the early stage, making liquid petroleum into solid bitumen. At present, oil and gas in the reservoir were largely formed in the late stage. During the continuous process in which shale was buried, light oil and gas were generated. Light oil and gas underwent magmatic and tectonic hydrothermal processes in some areas, resulting in high-temperature metamorphic cracking that formed dry gas. Moreover, nitrogen inclusions are found in fluid inclusions, forming metamorphic fluids caused by magmatic hydrothermal activities. The study shows that Paleozoic reservoirs in Xuanjing area are characterized by self-generation and self-storage. Furthermore, the mechanism of shale gas accumulation is not only related to the buried hydrocarbon generation process of shale itself, but is also related to later magmatic activity and tectonic hydrothermal transformation. Therefore, preservation conditions are generally key factors of shale gas accumulation in this area.

  Plenty of high-resolution paleoclimate investigations of the last thousand years were carried out to potentially predict future climate changes. Mountainous ombrotrophic peatland is one of the best recorders for high-resolution paleoclimate studies in the forest area. Grain size analysis was carried out on ombrotrophic peat proffle in the eastern mountainous region of Jilin Province, Northeast China. The peat proffle lasts the past 2 000 a by four radiocarbon (AMS14 C) ages. The results showed that the inorganic minerals in the peat proffle are mainly silt, with some contribution from clay and a minor amount of sand, which are mainly due to wind dust and suspended transportation. Two paleoclimate stages are found in this peat proffle by phytolith analysis, peat cellulose isotope research and historical documents: ca. 45–1550 AD, relatively cold period; ca. 1550 AD–present, relatively warm period. This ffnding is important for the initial study of paleoclimatic changes over the last 2 000 a in the mountainous area of eastern mountainous area, Jilin Province, Northeast China.

 In order to study fracture mechanism of rocks in di?erent brittle mineral contents, this study proposes a method to identify the acoustic emission signal released by rock fracture under di?erent brittle mineral content (BMC), and then determine the content of brittle matter in rock. To understand related interference such as the noises in the acoustic emission signals released by the rock mass rupture, a 1DCNN-BLSTM network model with SE module is constructed in this study. The signal data is processed through the 1DCNN and BLSTM networks to fully extract the time-series correlation features of the signals, the non-correlated features of the local space and the weak periodicity law. Furthermore, the processed signals data is input into the fully connected layers. Finally, softmax function is used to accurately identify the acoustic emission signals released by different rocks, and then determine the content of brittle minerals contained in rocks. Through experimental comparison and analysis, 1DCNN-BLSTM model embedded with SE module has good anti-noise performance, and the recognition accuracy can reach more than 90 percent, which is better than the traditional deep network models and provides a new way of thinking for rock acoustic emission research. 

 The vibrator plate is the link between the vibroseis vehicle and the earth, as well as the core component of the vibrator vehicle. In this paper, the coupling effect between the vibrator plate and the earth is analyzed from two aspects of reaction tooth arrangement and reaction tooth conical angle, and three groups of experimental models are optimized and designed. The model construction and numerical analysis of the shear wave vibroseis vibrator plate are carried out with ANSYS software.The motion law between the vibration plate and the earth at work was studied, the strain energy of the three experimental models in operation, the maximum displacement of particle at the same position and other reference indices were compared and analyzed, with 28 conical reaction teeth were arranged on both sides. The coupling effect between the vibration plate and the earth was best when the tooth angle was 60°. Compared with the toothless vibration plate, the energy efficiency is improved by about 20%, and the coupling effect between the vibrator plate and the earth is effectively enhanced. It is found that the coupling effect is enhanced through increasing the number of reaction teeth of the vibration plate by increasing the coupling area between the vibration plate and the earth.

 The exploration of urban underground spaces is of great signiffcance to urban planning, geological disaster prevention, resource exploration and environmental monitoring. However, due to the existing of severe interferences, conventional seismic methods cannot adapt to the complex urban environment well. Since adopting the single-node data acquisition method and taking the seismic ambient noise as the signal, the microtremor horizontal-to-vertical spectral ratio (HVSR) method can effectively avoid the strong interference problems caused by the complex urban environment, which could obtain information such as S-wave velocity and thickness of underground formations by fitting the microtremor HVSR curve. Nevertheless, HVSR curve inversion is a multi-parameter curve fftting process. And conventional inversion methods can easily converge to the local minimum, which will directly affect the reliability of the inversion results. Thus, the authors propose a HVSR inversion method based on the multimodal forest optimization algorithm, which uses the efffcient clustering technique and locates the global optimum quickly. Tests on synthetic data show that the inversion results of the proposed method are consistent with the forward model. Both the adaption and stability to the abnormal layer velocity model are demonstrated. The results of the real ffeld data are also veriffed by the drilling information. 

 It is of great significance to study the influence of spatial pattern change of cultivated land on ecosystem service, including the sustainable utilization and ecological protection in black soil region in Northeast China. Taking Lishu County of Jilin Province as the study area, we quantitatively evaluated soil conservation, habitat quality, carbon storage and grain production service, and analyzed the change of cultivated land and ecosystem service pattern in Lishu County from 1990 to 2020 by using Pearson correlation analysis on the correlation between cultivated land change and ecosystem service. The results show that: (1) The cultivated land area of Lishu County was reduced by 19.67 km2 , the characteristics of cultivated land change are significant; (2) the overall change rate of carbon storage, habitat quality, soil conservation and grain production service in the study area was 10.82%, −0.09%, 4.07% and 1.80%, respectively. They all had significant spatial differentiation features; (3) the change of habitat quality, grain production service showed a significant positive correlation with the change of cultivated land area. The change in soil conservation and carbon storage were negatively related to cultivated land area. In order to promote the rational development and utilization of cultivated land in the research area, it is suggested to scientifically carry out the comprehensive utilization of cultivated land reserve resources such as saline-alkali land, strengthen the management and protection of newly added cultivated land at the same time. The results can provide scientific reference for formulating comprehensive land use planning under ecological security conditions.

Flood disasters can have a serious impact on people's production and lives, and can cause huge losses in lives and property security. Based on multi-source remote sensing data, this study established decision tree classification rules through multi-source and multi-temporal feature fusion, classified ground objects before the disaster and extracted flood information in the disaster area based on optical images during the disaster, so as to achieve rapid acquisition of the disaster situation of each disaster bearing object. In the case of Qianliang Lake, which suffered from flooding in 2020, the results show that decision tree classification algorithms based on multi-temporal features can effectively integrate multi-temporal and multi spectral information to overcome the shortcomings of single-temporal image classification and achieve ground-truth object classification.

 Current data-driven deep learning (DL) methods typically reconstruct subsurface velocity models directly from pre-stack seismic records. However, these purely data-driven methods are often less robust and produce results that are less physically interpretative. Here, the authors propose a new method that uses migration images as input, combined with convolutional neural networks to construct high-resolution velocity models. Compared to directly using pre-stack seismic records as input, the nonlinearity between migration images and velocity models is signiffcantly reduced. Additionally, the advantage of using migration images lies in its ability to more comprehensively capture the reffective properties of the subsurface medium, including amplitude and phase information, thereby to provide richer physical information in guiding the reconstruction of the velocity model. This approach not only improves the accuracy and resolution of the reconstructed velocity models, but also enhances the physical interpretability and robustness. Numerical experiments on synthetic data show that the proposed method has superior reconstruction performance and strong generalization capability when dealing with complex geological structures, and shows great potential in providing efffcient solutions for the task of reconstructing high-wavenumber components. 

  Unmanned aerial vehicle transient electromagnetic (UAV-TEM) is a novel airborne exploration method that offers advantages such as low cost, simple operation, high exploration efffciency and suitability for near-surface exploration in complex terrain areas. To improve the accuracy of data interpretation in this method, the authors conducted a systematic three-dimensional (3D) forward modeling and inversion of the UAV-TEM. This study utilized the finite element method based on unstructured tetrahedral elements and employed the second-order backward Euler method for time discretization. This allowed for accurate 3D modeling and accounted for the effects of complex terrain. Based on these, the influence characteristics of ffight altitudes and the sizes, burial depths, and resistivities of anomalies are compared and analyzed to explore the UAV-TEM systems’ exploration capability. Lastly, four typical geoelectrical models of landslides are designed, and the inversion method based on the Gauss-Newton optimization method is used to image the landslide models and analyze the imaging effect of the UAV-TEM method on landslide geohazards. Numerical results showed that UAV-TEM could have better exploration resolution and ffne imaging of nearsurface structures, providing important technical support for monitoring, early warning, and preventing landslides and other geological hazards. 

Since the Paleozoic, the tectonic evolution of northeastern Eurasia has been primarily influenced by the Paleo-Asian Ocean and the Paleo-Pacific tectonic domains. However, the spatial and temporal frameworks, as well as the timing of the tectonic transition between these two oceanic domains, remain unclear. For addressing these issues, we present petrological, geochronological, and geochemical data for andesite and sandstone samples from the Seluohe Group along the Jilin-Yanji Suture between the Jiamusi Khanka Block and the North China Craton. The geochemical results indicate that the andesite sample is high-Mg andesite. Its magma source was generated by the metasomatized mantle wedge influenced by f luids derived from the subducted slab in a continental island arc setting. The high-Mg andesite gives the crystallization ages of Early Triassic (249±3 Ma). The sandstone is immature greywacke with a maximum depositional age of Early Triassic (247±1 Ma), and its sediments primarily originate from concurrent magmatic rocks within a juvenile continental arc. Based on our new findings, we propose that the Seluohe Group represents an Early Triassic volcanic-sedimentary association with continental island arc characteristics associated with the southwestward subduction of the Heilongjiang Ocean. We identified a sedimentary basin intimately associated with one or more continental arcs along the northeastern edge of the North China Craton. We suggest that the southwestward subduction of the Jilin-Heilongjiang Ocean in the Early Mesozoic accounts for this continental arc setting. There is a distinct temporal gap between the closure of the Paleo-Asian Ocean (ca. 260 Ma) and the onset of Paleo-Pacific plate subduction (234–220 Ma), which is essentially coeval with the southwestward subduction of the Jilin-Heilongjiang Ocean between 255 Ma and 239 Ma.

To determine the geological age, petrogenesis, and tectonic setting of Mesozoic volcanic rocks in the Ningyuancun Formation in Xunke area, Lesser Hinggan Range, the zircon U-Pb geochronology, petrographic observations, and geochemical analyses of major and trace elements were conducted in this study. Zircon U-Pb dating showed that the volcanic rocks of the Ningyuancun Formation were formed in the Early Cretaceous (112.97±0.90 Ma). Major element analyses revealed that the content of SiO? weighted from 74.14% to 76.54%, indicating the volcanic rocks to be high-silica and felsic. The content of AlO varies from 12.48% to 13.65%. A total alkali content of the volcanic rocks range between 8.46% and 9.56%, with Na?O/K?O ratios from 0.69 to 0.89. This indicated that the volcanic rocks belonged to a highly differentiated calc-alkaline series. Additionally, A/CNK values range from 0.950 to 1.015, and A/NK values vary between 0.999 and 1.127, suggesting a peraluminous characteristic. Trace element analysis showed a right-sloping “V-shaped” REE pattern, with the enrichment in light REEs and a prominent negative anomaly of Eu. The volcanic rocks are enriched in Rb, Th, U, La, and Ce, while Ba, Sr, and Ti are depleted. Rb/Sr ratio ranges from 10.01 to 12.46, Ti/Y ratio is from 51.14 to 95.72, and Ti/Zr ratio is from 5.78 to 6.41. It is suggested that the magma was derived from the partial melting of crustal rocks. This evidenced that the Early Cretaceous high-silica rhyolites were formed in an intra continental extension in eastern Northeast China during the northwestward subduction of the Pacific Plate. The crustal extension, asthenospheric mantle upwelling and underplating of mantle-derived magmas resulted in the residual crystalline mush in Early Cretaceous mafic magma chambers to erupt.

A genus within the family Douvillinidae of the order Strophomenida from the Erdaogou Member of the Xibiehe Formation in the Early Devonian of central Jilin has been re-examined, with consideration

The quest for enrichment model of continental shale oil in the Zhanhua Sag of the Jiyang Depression in the Bohai Bay Basin to provide reference for exploration and development requires a comprehensive approach. Therefore, this study employs rock pyrolysis, Scanning Electron Microscopy (SEM), X-Ray diffraction analysis (XRD), Nuclear Magnetic Resonance (NMR), and other experiments to analyze the conditions for shale oil enrichment and establish its patterns. The results show that favorable hydrocarbon generation potential and appropriate thermal maturation degree control “in situ enrichment”; while the storage capacity and the mobility of shale oil determine “migration enrichment.” In the process, the TOC governs the oil-generating capacity of shale with medium to large pores and microfractures serving as the main enrichment spaces and migration pathways for shale oil. Based on the deposition model, the study area can be divided into five lithofacies stages (I-algal limestone, II-laminated marl, III-laminated recrystallized limestone, IV-laminated mudstones, and IV-blocky calcareous mudstones). Integrating the geochemical parameters into the sedimentary patterns makes it clear that the study area underwent two phases of hydrocarbon expulsion during the thermal evolution of source rocks (Stage II: 3 060–3 120 m and Stage IV: 3 020–3 040 m). However, judging by the observed TOC (2% to 5.6%), thermal maturity (Ro>0.8%), S1 (>2 mg/g) and OSI (>100 mg/g) as well as moderate basin size, climate, and quantity of terrestrial input, the blocky calcareous mudstones (Stage IV) have better oil-prone characteristics and potential to generate a substantial quantity of hydrocarbons at this stage. More so, with a brittleness index exceeding 60%, it exhibits favorable fracturability accounting for the main controlling factors and enrichment patterns of shale oil in the area. Hence, this study further enriches and develops the theoretical understanding of shale oil enrichment in the area, provides valuable insights for future exploration of continental shale oil in eastern China and other similar basin around the world.

The Tangjiashan lead-zinc deposit, located on the southwestern margin of the Sichuan Basin, is rich in bitumen, and the lead-zinc ore and bitumen coexist closely, indicating a close genetic relationship between lead-zinc mineralization and hydrocarbon reservoir formation. However, whether bitumen shares the same source as the current gas reservoirs within the basin or other destroyed gas reservoirs along the basin margins remains unknown. Here, we conducted an organic geochemical analysis of bitumen in this deposit and identified the sources of hydrocarbons by comparing biomarker compounds with those of potential source rocks. The authors found that the bitumen in the Tangjiashan lead-zinc deposit has good comparability with the hydrocarbon source rocks of the Cambrian Qiongzhusi Formation, suggesting that the primary sources of oil in this ancient hydrocarbon reservoir are muddy source rocks of the Qiongzhusi Formation. This research is important for enhancing the understanding of the genetic connection between lead-zinc mineralization and hydrocarbon formation, providing crucial insights for strategies to explore both metal ores and hydrocarbons and advancing the geological understanding of petroleum systems in the Sichuan Basin.?

There have always been academic debates regarding the timing and geodynamics of the superimposition and transformation between the Paleo-Pacific Ocean and the Paleo-Asian Ocean. To resolve the relevant issues over this debate, the authors selected the Jilin–Heilongjiang high-pressure metamorphic belt (Ji–Hei HP Belt) between the Jiamusi–Khanka Block and the Songliao Block in NE China as the study area. This area preserves important records of the superimposition and transformation between these two tectonic domains. This study aims to address this issue through geochemical and zircon U–Pb dating analyses of the Yilan blueschist of Heilongjiang Complex exposed in the Ji–Hei HP Belt. In the geochemical analysis, it has been discovered that the protoliths of the blueschist in the Yilan area consist of subalkaline basalt, which displays geochemical characteristics of Ocean Island Basalt that indicated an oceanic island setting. The LA–ICP–MS zircon U–Pb analysis yields ages of 248±4 Ma and 259±2 Ma from the magma zircons of the blueschists, indicating that the basalt protolith was formed in Late Permian to Early Triassic (259–248 Ma). Based on the results of this study and the regional data, it is proposed that the Jilin–Heilongjiang Ocean opened during Late Permian to Early Triassic (259–248 Ma). This period marks a crucial stage from the closure of the Paleo-Asian Ocean to the initiation of Paleo-Pacific oceanic subduction.

During Early Cretaceous, NNE-trending extensional basins filling with various volcanic sedimentary formations developed in the northeastern Da Hinggan Ling (Mts.), northeastern China. This study investigates the formation age and geological background of Jiufengshan Formation, providing insights into its tectonic setting and formation mechanisms. Detrital zircons from four sandstone samples of Jiufengshan Formation in Nenjiang area indicate a maximum depositional age of 116±1 Ma, corresponding to late Early Cretaceous. Petrographic analysis and zircon age peak comparisons suggest these sandstones originated from proximal deposits with nearby provenances of earlier and contemporaneous volcanic rocks. Further research on the sandstone framework and trace elements in detrital zircons indicates that the formation process of Jiufengshan Formation was likely related to the low-angle subduction of the Paleo Pacific plate.

This study presents LA–ICP–MS U–Pb dating and whole-rock geochemical analyses of the Late Triassic Gangshan harzburgite in the Qingyuan area, with the aim of elucidating its petrogenesis and further constraining the early Mesozoic tectonic evolution of the eastern segment of the northern margin of the North China Block (NCB). Zircons from the harzburgites exhibit typical oscillatory growth zoning or striped absorp tion in cathodoluminescence images. U–Pb analyses of zircons yield ages ranging from 2 525 Ma to 225 Ma, with two youngest ages (225±7 Ma) indicating that the harzburgites were formed during Late Triassic. Geochemical analyses of the Gangshan harzburgites show that the rocks have low concentrations of SiO2 (42.38%–42.85%) and Al2 O3 (3.31%–3.33%), along with high concentrations of MgO (41.32%–41.76%), Cr (4 856×10-6–5 191×10-6) and Ni (1 942×10-6–2 041×10-6). They also display low REE abundances (∑REE=4.38×10-6–4.69×10-6) and flat REE patterns with low (La/Yb)N ratios (1.24–1.56) and slightly po- sitive Eu anomalies (δEu=1.13–1.16). These features suggest that the Gangshan harzburgites are cumulates of basaltic magma derived from the depleted lithospheric mantle. Combined with previous studies, these Late Triassic mafic–ultramafic rocks, together with coeval granitoids in adjacent regions, constitute a typical bimodal association, suggesting that they formed in a post-orogenic extensional environment after the final closure of the Paleo-Asian Ocean.

This study selects geochemical data of basalts from different seamounts in the Mid-Pacific Mountains province and conducts analyses of major and trace elements as well as Sr-Nd-Pb isotopes to explore the tectonic evolution, petrogenesis, and mantle-source magama characteristics of the Mid-Pacific Mountains. The basalts from the Mid-Pacific Mountains are predominantly alkali basalts, rich in alkalies, and changing in potassium. They exhibit geochemical features of ocean island basalts (OIB), with distinct fractionation between light and heavy rare-earth elements and a pronounced Ce negative anomaly (δCe = 0.16–1.10, average 0.84), along with enrichment in large ion lithophile elements (LILEs). The Mid-Pacific Mountains are intraplate ocean island basalts formed by mantle plume (hotspot) activity, originating mainly from an enriched mantle magma source region, and most of them have undergone low degree of partial melting and a certain degree of crystalline differentiation, with negligible contamination from oceanic crust materials. The Mid-Pacific Mountains exhibit ratios of 87Sr/86Sr(i) (0.702 733–0.704 313, average 0.703 452) and 143Nd/144Nd(i) (0.512 698–0.512 996, average 0.512846) which are close to the HIMU mantle end member, and ratios of 206Pb/204Pb (18.953–19.803), 207Pb/204Pb (15.54–15.62) and 208Pb/204Pb (38.813–39.514) which are close to the EMII mantle end-member. Combined with the isotopic geochemical characteristics in the West Pacific Seamounts province, the basalts from the Mid-Pacific Mountains were considered to represent a certain proportion of mixing mantle end-members between the HIMU and EMII, possibly formed by the mixing of the HIMU superplume in the South Pacific hotspot region with the EMII secondary mantle plume in the transition zone during their ascent.

Groundwater overexploitation is the main cause of city surface deformation. In Siping City, groundwater level had decreased since 1980 due to large-scale exploitation of groundwater. Subsequently, the level began to rise under governance while shown a declining trend in the whole Siping area. This paper obtained surface deformation of Siping City from 2017 to 2024 using 36 Sentinel-1B satellite images and 88 Sentinel-1A satellite images based on SBAS-InSAR and analysed the effect of groundwater on deformation. The results indicated that uplift occurs in the centre of the urban area with a maximum average velocity of about 5 mm/y and there were two main subsidence zones during these two time periods with average subsidence velocities of about 3 mm/y and 1.7 mm/y. Groundwater levels showed a high correlation with surface deformation, with rising the levels leading to surface uplift and falling the levels leading to surface subsidence.

 Recurring Slope Lineae (RSL) are seasonally observed dark streaks on the Martian surface that exhibit distinct spatial and temporal distribution characteristics. Exploring their formation mechanisms can deepen our understanding of surface activity on Mars and provide scientific basis for future Mars exploration. This study aims to gain a comprehensive understanding of the spatial and temporal distribution characteristics and formation mechanisms of RSL by reviewing relevant literature and synthesizing various viewpoints and experimental results. RSL typically appear during warm seasons, disappear during cold seasons, and repeat over multiple Martian years. The formation mechanisms can be broadly categorized into three types: dry mode, wet mode, and mixed mode. However, a definitive explanation for the formation of RSL is still lacking, and both the dry and wet models have their respective limitations. It is likely that the formation of RSL is the result of the combined action of multiple mechanisms. The next step should be to search for terrestrial analogs of RSL and conduct research at high spatial and temporal resolutions to understand the forming processes of RSL.

The lower member of Dalazi Formation is an important oil reservoir in the Songjiang Basin. Based on the research on its field-measured geological profiles, lithological combination characteristics and grain size distribution characteristics, combined with the analysis of the spatial distribution characteristics, sedimentary structural characteristics and hydrodynamic conditions of the sediments in this member, nine sedimentary microfacies of the fan delta plain subfacies, fan delta front subfacies and littoral-shallow lacustrine subfacies have been identified.The study reveals that lower member of Dalazi Formation in the research area follows a fan delta–shallow lacustrine depositional model in the steep slope zone of a rift lake basin. The sediments primarily originate from the Pre-Mesozoic strata in the steep southeastern and eastern margins. The basin center migrated from the early Xiaoshahe area to the Yangmucun–Shenglicun area, and the sedimentary system gradually transitioned from fan delta to littoral-shallow lacustrine facies.

The Longfengshan structural belt lies in the southern Changling Depression. The Yingcheng Formation is the primary gas-bearing unit. The Yingcheng Formation has low permeability and contains deep, tight gas that is challenging to extract. Industrial gas flow has been achieved from the B218 and B220 well blocks in the sandstone layer of the first member of Yingcheng Formation (Ying I), indicating the potential of this sandstone group for gas production. Although oil and gas are widely distributed in the Ying I sandstone layer, production capacity varies significantly across the formation. into six sublayers. Drilling, logging, and laboratory testing data were integrated to subdivide the Ying I sandstone layer into six sublayers. Core and well logging analyses indicate a braided river delta depositional environment. Data and seismic inversion identify the Ying I-5 sublayer as the primary exploration target. The effective reservoir in the eastern fan body, where porosity ranges from 5% to 13% and maximum effective thickness reaches 34 m. This study basis for optimizing well placement and estimating gas reserve parameters in the Ying I sandstone layer of the Longfengshan area. The findings can guide the development of other tight gas reservoirs.

 The pore structure of rocks significantly influences the porosity and permeability of reservoirs and the migration ability of oil and gas, and being the key task on the development of volcanic gas reservoirs. Nine volcanic rock samples from the Yingcheng Formation and Huoshiling Formation in the Longfengshan area of the Changling Fault Depression in the Songliao Basin were selected for this study. The pore structures of the volcanic rocks in the study area were investigated using high-pressure mercury injection, X-ray diffraction combined with fractal theory. The relationships between the fractal dimension and physical properties characteristics, pore structure parameters, and mineral content were analyzed to provide guidance for the development of volcanic rock gas reservoirs. The results show that the reservoir can be divided into 3 types (I, II, and III) based on the shape of the capillary pressure curve, and the physical properties deteriorate successively. Different types of reservoirs exhibit different fractal characteristics. For types I, II and III, the average total fractal dimensions were 2.3418, 2.6850, and 2.9203, respectively. The larger the fractal dimension, the stronger the heterogeneity of reservoir. A small number of macro-pores primarily contributed to permeability. The fractal dimension was negatively correlated with porosity and permeability. The fractal dimension of the rock was strongly correlated with quartz and feldspar contents, and the mineral composition and content are closely related to the pore evolution of the reservoir, which are the internal factors affecting the fractal dimension of volcanic rock.