South Tianshan–Solonker suture, is the largest and southernmost suture within the Central Asian orogenic belt (CAOB). It records the ultimate collision between Tarim–North China cratons and Siberia craton, and is commonly interpreted as marking the eventual closure of Paleo-Asian Ocean. South Tianshan suture belongs to the western segment of the suture zone, and its evolutionary features are important for defining the formation age of the South Tianshan–Solonker suture. In this paper, the authors review the geochronological, geochemical, petrographic, and paleontological evidence within South Tianshan suture to delineate its formation era and closure characteristics, and thus further revealing the ultimate evolutionary pattern of the western segment of Paleo-Asian Ocean. This suture records strong plate collision before Late Carboniferous, forming a series of high-pressure metamorphic rocks, characterized by the presence of blue schist, eclogite and mica schist. In Permian, the whole area was under a relatively stable post-orogenic setting, with the formation of bimodal volcanic rocks, post-collisional granites, and terrestrial molasses. Sedimentary facies gradually changed from marine to either lacustrine or fluvial during this period. An Early Permian granite dike crosscuts the HP metamorphic belt, and the HP metamorphic rocks also underwent retrograde metamorphism at this time, indicating the formation of the South Tianshan suture was earlier than Permian. Hence, the western section of Paleo-Asian Ocean closed during Late Carboniferous, and Tarim Craton moved northward to collide with Kazakhstan–Yili Block, leading to the formation of the South Tianshan suture

 The Group II fresh groundwater bearing aquifers in the eastern plain of Tianjin underwent long term exploitation. This study shows that the area with greater water-level declining is associated with more rapid stratigraphic compaction and consolidation. In the study area, the salty groundwater in the un-exploited overlying aquifers have the same dynamic characteristic of synchronization but different amplitude with the Group II aquifers, showing that they have a close relationship. Cross-sectional study indicated that surface water, salty groundwater and underlying fresh groundwater belong to an integral water resources system. The compacted clay layers have the feature of semi-permeable membrane under alkaline condition. The infiltration of surface water is driven by the differences of osmotic pressure of salty water in each layer. When the water level difference between the Group II aquifers and overlying salty aquifers is greater than osmotic water pressure difference, the salt water layer will desalinate downward and eventually, decreasing the water level of the upper aquifers, turning phreatic water amount supposed to evaporate to leakage recharge. Therefore, stopping mining groundwater in the Group II aquifer will lead to other new environmental geology disaster.

  In order to improve the matrix performance of impregnated diamond drill bit to better meet the drilling needs, the effects of the addition of nano-WC and nano-NbC particles on the matrix material together with the mechanical properties and microstructure of the diamond-matrix composite material of the Fe-based diamond drill bit were studied by using the method of uniform formula design, regression analysis and solution finding. An indoor drilling test was also carried out using the fabricated impregnated diamond drill bit. The results showed that after the addition of nano-NbC and nano-WC, the hardness and flexural strength of the matrix material got improved, as the flexural strength of the diamond composite material increased to 4.29%, the wear-resistance ratio increased to 8.75%, and the tighter the chemical bonding between the diamond and the matrix. This, indicates that the addition of nanoparticles has a positive significance in improving the performance of the diamond composite. The results of the drilling test showed that the mechanical drilling speed of the impregnated diamond drill bit after nanoparticle strengthening is 25.85% higher than that of the conventional drill bit, and the matrix wear was increased by 17.5%. It proves that nanoparticles can improve the drilling performance and efficiency of drill bit.

 Down-the-hole (DTH) hammer with casing while drilling (CWD) is a technology that has been proven to be able to alleviate many of the problems faced by complex formations. However, the drill bit is suffered from rapid wear, low drilling efficiency, and high energy consumption due to the unreasonable tooth arrangement and impact energy selection in drilling process, which affect the application effect of this technology. ABAQUS software was used for numerical simulation of rock breaking behavior under impact load with the single, three, and five teeth arrangement drill bit respectively, to improve the application effect and solve the aforementioned technical problems. Based on the calculated parameters of tooth arrangement, we designed a novel drill bit for hard rocks and provided a theoretical basis for the tooth arrangement of largediameter drill bits.

 Casing-while-drilling (CWD) with down the hole (DTH) hammer drilling technology has been widely used in unconsolidated formations, due to its advantages in protecting the borehole wall, excellent rock cuttings capacity, and fast penetration rate in hard rock. As an important component of the CWD system, the structure of the retractable drill bit needs not only to ensure to form stronger reverse circulation, but also to be expandable or retractable as needed, otherwise the drill bit cannot be lift and put down smoothly in the casing, and may lead to drilling accidents. This paper developed a new type of reverse circulation DTH hammer drill bit used for CWD drilling technology. The retractable performance of this type of drill bit is studied using ADAMS software. The results show that it is smoothly expandable and retractable as designed under the conditions of the weight of the bit (WOB) of 0.5–2.0 t and the rotation speed of 30–60 r/min. To investigate the reverse circulation effect of the drill bit, Fluent software was used to simulate the flow characteristic inside it. The simulation results indicated that it can form strong reverse circulation, and the entrainment ratio h can reach 9.5%.

  Pleuromeia is an Early-Middle Triassic index lycopod plant, very significant for study of floral age, paleoecology and paleogeography. In recent years, the progresses in the study of Pleuromeia include the new taxon Pleuromeia shaolinii Zhang et Wang found from the Middle Triassic Lianjia flora in Benxi, China; and a new strobilus of Pleuromeia found from the Lower Triassic of Nevada, USA. Four species of Pleuromeia were selected by Mendelin et al. (2022) as the iconic taxa for four ages from the Lower to Middle Triassic in the world (including the Chinese species P. shaolinii), which is more significant for paleogeographic and evolutionary studies of Pleuromeia.

  Clastic rock reservoir is the main reservoir type in the oil and gas field. Archie formula or various conductive models developed on the basis of Archie’s formula are usually used to interpret this kind of reservoir, and the three-water model is widely used as well. However, there are many parameters in the threewater model, and some of them are difficult to determine. Most of the determination methods are based on the statistics of large amount of experimental data. In this study, the authors determine the value of the parameters of the new three-water model based on the nuclear magnetic data and the genetic optimization algorithm. The relative error between the resistivity calculated based on these parameters and the resistivity measured experimentally at 100% water content is 0.902 4. The method studied in this paper can be easily applied without much experimental data. It can provide reference for other regions to determine the parameters of the new three-water model.

 Large-scale tectonic magmatism and extensive gold mineralization have occurred in the eastern North China Craton (NCC) (Jiaodong and Liaodong peninsulas) since Mesozoic, which indicated that the region experienced decratonization process. The genesis type of granites evolved from S-type to I-type and A-type during Late Jurassic to Early Cretaceous, and thus reflects the evolution of geodynamics in the Late Mesozoic, indicating the varied subduction process of the Paleo-Pacific Plate (PPP) and the craton destruction. The evolution of geochemical features shows that the mantle beneath the Jiaodong Peninsula evolved from EM-II in Jurassic to EM-I in Early Cretaceous, demonstrating that the mantle switched from enriched to depleted. The gold of decratonic gold deposits in Jiaodong Peninsula mainly comes from the lithospheric mantle domains metasomatized by fluids derived from the metamorphism and dehydration of the subducted slab in the mantle transition zone. The rapid decomposition of minerals leads to the concentrated release of ore-forming fluids, and this process leads to the explosive gold mineralization during the craton destruction. Extensive magmatic uplift and extensional structures, triggered by the craton destruction in Early Cretaceous formed the extensional tectonic system, providing space for the decratonic gold deposits in Jiaodong Peninsula.

 Based on the field survey of Lower Jurassic Badaowan Formation (Fm.) in Changji area of Xinjiang, China, the authors studied the sedimentary environment and provenance characteristics using the analyses of stratigraphic profiles, sedimentary structures, petrography, zircon U-Pb chronology and geochemistry. The results show that Badaowan Fm. deposited in fluvial to swamp shallow-deeplacustrine sedimentary facies deposition. Contents of Sr and ratios of Sr/Cu, Sr/Ba, Th/U, SiO2/Al2O3, V/(V+Ni), V/Cr, and Cu/Zn together indicate that Badaowan Fm. was deposited in an oxygen-poor transitional freshwater environment, under humid climatic conditions. Geochemical characteristics and Q–F–L, Qm–E–Lt , Th–Co–Zr/10, La–Th–Sc, and Th–Sc–Zr/10 discrimination diagrams indicate that the tectonic setting of the source area was a continental island arc environment. Lithological composition, Th/U ratios, and Co/Th–La/Sc, La/Th–Hf, and La/Yb–REE discrimination diagrams show that the source rocks of Badaowan Fm. were upper-crust felsic volcanic rocks. U-Pb dating of detrital zircons yields ages of 1 542.3±15.0 to 232.9±3.3 Ma and mostly in the ranges of 470–410 and 370–280 Ma. A comparison of these ages with the age data from different blocks of crystalline rock in Tianshan Mountains area reveals that the sedimentary rocks in the Badaowan Fm. were sourced predominantly from the central and subordinately from the southern Tianshan Mountains during Early Jurassic.

 Traditionally, plant distribution is thought to be closely related to environmental factors. But recently, it is found that Populus, quite different from other plant taxa, adapted to negative environmental changes, and successfully migrated to different climate zones from its origin places of warm temperate zone. Conversely, Metasequoia is gradually tending to extinction from the Miocene to Quaternary. Based on above contrary cases, two response patterns of plant to negative environmental changes are proposed. One is active adaptation represented by Populus, the other is passive adaptation represented by Metasequoia. The plants of passive strategy characterized for desert prevention might be easily replaced by those of active strategy characterized for desert utilization. Fast growing plants, such as Populus with characteristics of drought and salt tolerance, wind and sand resistance, are selected in Tarim Basin in southern Xinjiang, China, as a good example of desert utilization in the construction of new highways and towns, not only serve as farmland shelterbelt in sandy area. In addition, Populus with high-altitude and cold adaptation has also been selected as an ideal tree planted in Tibet. Therefore, the idea of using Populus as one of the preferred pioneer trees to colonize Mars is proposed.

 Highly accurate vegetative type distribution information is of great significance for forestry resource monitoring and management. In order to improve the classification accuracy of forest types, Sentinel-1 and 2 data of Changbai Mountain protection development zone were selected, and combined with DEM to construct a multi-featured random forest type classification model incorporating fusing intensity, texture, spectral, vegetation index and topography information and using random forest Gini index (GI) for optimization. The overall accuracy of classification was 94.60% and the Kappa coefficient was 0.933. Comparing the classification results before and after feature optimization, it shows that feature optimization has a greater impact on the classification accuracy. Comparing the classification results of random forest, maximum likelihood method and CART decision tree under the same conditions, it shows that the random forest has a higher performance and can be applied to forestry research work such as forest resource survey and monitoring.

  The impregnated diamond (ID) bit drilling is one of the main rotary drilling methods in hard rock drilling and it is widely used in mineral exploration, oil and gas exploration, mining, and construction industries. In this study, the quadratic polynomial model in ID bit drilling process was proposed as a function of controllable mechanical operating parameters, such as weight on bit (WOB) and revolutions per minute (RPM). Also, artificial neural networks (ANN) model for predicting the rate of penetration (ROP) was developed using datasets acquired during the drilling operation. The relationships among mechanical operating parameters (WOB and RPM) and ROP in ID bit drilling were analyzed using estimated quadratic polynomial model and trained ANN model. The results show that ROP has an exponential relationship with WOB, whereas ROP has linear relationship with RPM. Finally, the optimal regime of mechanical drilling parameters to achieve high ROP was confirmed using proposed model in combination with rock breaking principal.

 It is not easy to construct a model to describe the geochemical background in geochemical anomaly detection due to the complexity of the geological setting. Isolation forest and its improved algorithms can detect geochemical anomalies without modeling the complex geochemical background. These methods can effectively extract multivariate anomalies from large volume of high-dimensional geochemical data with unknown population distribution. To test the performance of these algorithms in the detection of mineralization-related geochemical anomalies, the isolation forest, extended isolation forest and generalized isolation forest models were established to detect multivariate anomalies from the stream sediment survey data collected in the Wulaga area in Heilongjiang Province. The geochemical anomalies detected by the generalized isolation forest model account for 40% of the study area, and contain 100% of the known gold deposits. The geochemical anomalies detected by the isolation forest model account for 20% of the study area, and contain 71% of the known gold deposits. The geochemical anomalies detected by the extended isolation forest algorithm account for 34% of the study area, and contain 100% of the known gold deposits. Therefore, the isolation forest model, extended isolation fo-rest model and generalized isolation forest model are comparable in geochemical anomaly detection.

 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. 

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.

 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. 

  Jilin City is a typical river valley city in Northeast China. In this paper, the authors studied the spatial and temporal expansion characteristics of the built-up areas in Jilin City from 1990 to 2020 using the analysis of expansion speed and strength, fractal dimension, barycenter coordinate transfer index and sector analysis. The ultimate-goal is to analyze the driving and restrictive factors that affect the spatial expansion of river valley cities. The results indicate that (1) the expansion speed of urban land in Jilin City has been relatively slow in the past 30 years, while only slightly faster in 2010–2020; (2) in the spatial dimension, Jilin City mainly expanded to the south, then to the west, and extensive expansion has resulted in complex morphology with little stability and compactness; (3) the expansion is affected by multiple factors, of which the positive factor is industrial development, while the restrictive factors include natural factors, population loss, etc. This study provides a case for the formulation of land use policies and land space planning in river valley cities.

 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. 

 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.

  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. 

 Altered igneous reservoirs have low porosity and permeability, compact structure and certain heterogeneity. A simple digital core with certain generality and multi-parameter constraints can be constructed to characterize the microscopic pore structure and mineral composition. In this paper, based on core X-ray, CT images and whole-rock mineral analysis, threshold segmentation of mass content and grayscale distribution of various minerals in different lithologies of igneous rocks in the buried hill of Huizhou depression is carried out to construct digital core of altered igneous rocks. The results show that after converting the mineral mass content into volume content, the minerals of altered igneous rocks in Huizhou depression can be classified into components. According to the range of grayscale value, components can be divided into six parts. Due to the difference of the content of components in different lithologies of igneous rocks, differentiated grayscale threshold segmentation is needed to obtain the digital core for a single lithology. The final digital core generation process includes two steps: building a single component digital core, and stacking and combining. This kind of universal digital core model can support the subsequent pore scale numerical simulation and comprehensive rock physics research.

 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.

 Based on five types of conventional logging curves including GR, RLLD, CNL, DEN and AC, and 39 core samples from 30 representative boreholes, the logging characteristics and lithofacies and sub-facies of the basaltic rocks were studied. Three basaltic facies and four sub-facies are recognized from the well logs, including volcanic conduit facies (post intrusive sub-facies), explosive facies, and effusive lava flow facies (tabular flow, compound flow and hyaloclastite sub-facies). The post intrusive, tabular flow and compound flow subfacies logging curves are mainly controlled by the distribution of vesiculate zones and vesiculate content, which are characterized by four curves with good correlation. Post intrusive sub-facies are characterized by high RLLD, high DEN, with a micro-dentate logging curve pattern, abrupt contact relationships at the top and base. Tabular flow sub-facies are characterized by high RLLD, high DEN, with a bell-shaped log curve pattern, abrupt contact at the base and gradational contact at the top. Compound flow sub-facies are characterized by medium-low RLLD, with a micro-dentate or finger-like logging curve pattern, abrupt contact at the base and gradational contact at the top. Explosive facies and hyaloclastite sub-facies logging curves are mainly controlled by the distribution of the size and sorting of rock particles, which can be recognized by four kinds of logging curves with poor correlation. Explosive facies are characterized by low RLLD, medium-low CNL and low DEN, with a micro-dentate logging curve pattern. Hyaloclastite sub-facies are characterized by low RLLD, high CNL, low DEN and high AC, with a micro-dentate logging curve pattern. The present research is beneficial for the prediction of basaltic reservoirs not only in the Liaohe depression but also in the other volcanic-sedimentary basins.

 Zircon U-Pb isotope dating and whole-rock geochemical analyses were undertaken for the rhyolite, rhyolitic lithic crystal tuff and dacitic tuff from the Manketouebo Formation in the Keyihe area, in order to constrain their genesis and tectonic significance. Zircon LA-ICP-MS U-Pb data indicate that the rhyolite and rhyolitic lithic crystal tuff were formed during 137±5 Ma and 143±1 Ma，respectively. These volcanic rocks have high SiO2 (70.03%–76.46%) and K2O+Na2O (8.10%–9.52%) contents, but low CaO (0.03%–0.95%) and MgO (0.07%–0.67%) contents, which belong to the peraluminous and high-K calc-alkaline rocks. They are enriched in light rare earth elements (REEs), and exhibit fractionation of light over heavy REEs, with δEu values of 0.37–0.83. The volcanic rocks are enriched in LILEs (e.g., Rb, U and K) and depleted in HFSEs (e.g., Nb, Ti, P and Ta). The chemical composition suggests that these volcanic rocks formed by partial melting of crust material. Combined with previous regional research results, the authors consider that the volcanic rocks of the Manketouebo Formation in the Keyihe area were formed under an extensional environment related to the closure of the Mongolia–Okhotsk Ocean.

 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.

  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. 

  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.

  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 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. 

 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. 

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.

 The hidden water-bearing structures near the roadway tunnelling face are very likely to cause water seepage accidents in coal mines. Currently, transient electromagnetic (EM) technology has become an important method to detect water damage in advance of roadway excavation. In this paper, the time-domain finite element algorithm based on unstructured tetrahedron grids is used to accurately simulate the geological body in front of the roadway excavation face and analyze its response. The authors detect the distance between the roadway excavation face and the low-resistivity water-bearing body, the resistivity difference between the low-resistivity body and surrounding rock, and the influence of the size of the low-resistivity body on the transient EM response. Furthermore, the common types of low-resistivity bodies in the roadway drivage process are used for modeling to analyze the attenuation of the detected EM response when there are low-resistivity bodies in front of the roadway. The research in this paper can help effectively detecting the water-bearing low-resistivity body in front of the roadway drivage and lay a foundation for reducing the risk of water seepage accidents.

 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 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 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. 

  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. 

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.