In order to constrain the tectonic evolution of the eastern part of the Jiao-Liao-Ji Orogenic Belt,the authors carried out a study on the petrogenesis and diagenetic tectonic background of the metamorphic gabbrocarbonatite complex in the Daxing iron mining area by using petrology, petrochemistry, petrogeochemistry and zircon U-Pb dating.The results show that the metamorphic gabbro-carbonatite complex in the Daxing iron mining area has the rock types of meta-gabbro, carbonatite and magnet ore body, and the mata-gabbro is the main rock type.Petrochemical study of the meta-gabbro showed that the w (SiO2) is from 44.23% to 48.80%, w (Na2O) is from 0.94% to 2.86%, w (K2O) is from 0.51% to 1.90%, w (TiO2) is from 0.42% to 0.93%, w (CaO) is from 8.73% to 14.78%, and the Na2O/ K2O ratio ranges from 1.12 to 2.27, MgO/ (FeO+MgO) ratio ranges from 0.54 to 0.60, (Mg2++Ni2+) / (Fe2++Fe3++Mn2+) ratio ranges from 1.44 to 2.02, Mg/ (Mg+Fe2+)ratio ranges from 0.60 to 0.68, and the differentiation index (DI) ranges from 11.76 to 31.79.The meta-gabbro rocks are basic-ultrabasic magma which is rich in iron and sodium, poor in potassium and titanium, and weak in differentiation.Geochemical studies show that the rocks are rich in large ion lithophile elements such as Rb, Ba [w (Rb) (4.80×10-6-74.82×10-6), w (Ba) (83.09×10-6-430.10×10-6)], and relatively rich in high field strength elements such as Hf, Th, Ta [w (Hf) (1.41×10-6-6.20×10-6), w (Th) (0.51×10-6-28.91×10-6),w (Ta) (0.47×10-6-9.91×10-6)], and ΣREE=(29.56×10-6-812.59×10-6 ); while, Nb is obviously depleted [ w (Nb) (2.94× 10-6-36.01× 10-6 ) ].The (Na2O+K2O) / TiO2 ratio is 0.10-5.54, Zr/ Y ratio is 1.93-5.67, La/ Nb ratio is 0.54-1.73, La/ Ta ratio is 5.53-11.13, Nb/ U ratio is 1.51-14.23.The geochemical characteristics are similar to continental tholeiitic basalts, and having the properties of intra-plate alkaline basalts.The carbonatite and meta-gabbro are interbedded.The average CaO/ (CaO+MgO+Fe2O3+FeO+MnO) ratio is 0.98, mean w (MgO) is 0.62, and mean w (FeO+Fe2O3+MnO) is 0.41.It is calcareous metamagnesic carbonatite which obviously rich in Sr [w (Sr) (1 727×10-6-1 794×10-6)].The complex magma may come from the partial melting of the asthenosphere enriched mantle, formed in the tectonic background of the stretching of the deep fault zone in the continental plate, and assimilated and mixed with crustal materials in a certain extent during the ascent.Most of the meta-gabbro zircons have the core-rim structure, the color of the core is mostly black.It is difficult to observe its internal structure, a few of the core can be seen wide oscillating bands.The Th/ U ratio is 0.23-4.19, which shows the characteristics of basic magmatic zircon.The weighted average age of 207Pb/ 206 Pb of the core is (2 098 ± 11) Ma (MSWD=1.2, n=18), which represents the condensation crystallization age of the gabbro.The color at the rims of the zircons is relatively light and uniform, without zonation,and the Th/ U ratio is 0.03-3.22, indicating metamorphic origin.The weighted average age of 207Pb/ 206Pb of the rims is (1 892 ±23) Ma (MSWD=2.2, n=14), which represents the metamorphic age of gabbro.Combined with regional geological data, it is considered that the eastern part of the Jiao-Liao-Ji Orogenic Belt was in a extensional tectonic environment in the Middle Paleoproterozoic, the formation of metamorphic gabbro-carbonatite complex in the Daxing iron mining area may be related to the extension during the tectonic evolution of the Songjiang-Chongshan fault zone.

In order to ascertain the petrogenesis，geotectonic setting and genetic connection with Late Triassic granites of the Early Jurassic granodiorites in Yeniugou area of Golmud City，the authors systematically conducted whole-rock geochemical，zircon U-Pb dating and Lu-Hf isotopic studies on the above issues. The results show that the zircons of Yeniugou granodiorites exhibit typical magmatic zircon oscillatory zoning and Th/U values (0.25-1.28，>0.10)，with weighted average age and εHf(t) value of (198.4±1.6) Ma and 4.99-7.50，respectively. In geochemistry，the Yeniugou granodiorites show the geochemical properties of C-type adakitic rock，including high Sr [(400×10-6)-(420×10-6)] but low Mg [w(MgO)=0.95%-1.19%]，Y [(6.93×10-6)-(7.87×10-6)] and Yb [(0.65×10-6)-(0.77×10-6)] contents，with typical low Na2O/K2O ratios (1.12-1.34，<2)，relative depletion of heavy rare earth elements and high field strength elements. Based on the geotectonic evolution，it can be inferred that the primary magma of Yeniugou granodiorites originated from the partial melting of Neopro-terozoic lower crustal amphibolite (TDM2=919-759 Ma). It is a continual magmatism of the Late Indosinian，and emplaced within the same geodynamic setting as the Late Triassic granitoids in a strong extensional background that was caused by the lower crustal delamination after the closure of Paleo-Tethys Ocean and orogeny.

As an important unconventional oil and gas reservoir unit，the formation and distribution of diabase are often controlled by their tectonic settings. Using petrology，geochemistry，and Sr--Nd isotopes geochemistry，the authors discuss the geochemical characteristics and geodynamic background of diabase of Es3 Member in Linnan Subsag，Bohai Bay Basin. The results show that the diabase belongs to the series of alkaline basalts with high Al，low Ti and enriched Na. The large ion lithophile elements (Rb，Ba，Pb，Sr) and light rare earth elements are relatively enriched，while the high field strength elements (Th，U) are relatively depleted，exhibiting a positive Eu anomaly. The diabase in the study area originates from the asthenosphere mantle，which is the result of mixing between different crust-mantle boundary zones. The formation of diabase is associated with intraplate magmatic activities，which suffered contamination by crustal materials during magma emplacement，occurring under a continental extensional tectonic setting. The Cenozoic extension in the Bohai Bay Basin occurred under an active rift environment，where the upwelling of the asthenosphere mantle was closely associated with the subduction of the Pacific Plate beneath the Eurasian Plate and the development of an intraplate mantle plume.

Through the field geological mapping, the geological setting and its mineralization characteristics for tanzanite deposit at Merelani area, Tanzania are described in details, especially the occurrences of orebodies and characteristics of gemstone are analyzed and reviewed, further its genetic model is discussed preliminarily. It is considered that tanzanite has been formed in the altered graphite gneiss which distributed in the Neoproterozoic Mo⁃ zambique metamorphic belt at proximately 500 Ma when the Pan⁃⁃African movement was taken place. Being a skarn deposit related to the contact metasomatism, the lithostratigraphic and tectonic deformation are two main controlling factors. 

To explore the geodynamic mechanisms of the large-scale magmatic activity during Early Cretaceous in Da Hinggan Ling (Mts.), the authors focused on diabase in Huoluotai area in northern segment of Erguna Block,Da Hinggan Ling (Mts.), through the study of petrogeochemical characteristics and zircon U-Pb dating of diabase in Huoluotai area, aimed to determine its formation age, petrogenesis, and tectonic setting.Zircon LA -ICP -MS U –Pb dating results show that the weighted average age of diabase in Huoluotai area is (135.1 ±3.6) Ma, indicating that the crystallization age of diabase is Early Cretaceous.Whole rock geochemical data reveal that diabase in Huoluotai area is characterized by low w (SiO2) (48.84%-52.11%), high w (MgO) (5.13%-6.85%) and w (Fe2O3) (7.45%-8.60%).The Eu anomaly of diabase is insignificant or exhibits a weak negative anomaly (δEu =0.83-1.06).The diabase is enriched in large ion lithophile elements (such as Ba, Sr, and K), and depleted in high field strength elements (such as Zr, Ta, Nb, and Th).Diabase in Huoluotai area is only minimally influenced by fractional crystallization, crustal contamination, and accumulation processes.The Nb/ Yb -Th/ Yb diagram shows that diabase in Huoluotai area falls within the area of primitive mafic melts derived from subduction-modified lithospheric mantle.The Th/ Nb-Ba/ Th and Th/ Yb-Ba/ La diagrams indicate that the magma source of diabase in Huoluotai area was modified by fluids derived from subducted slabs.The La/ Nb-La/ Ba diagram reveals that the magma source of diabase in Huoluotai area is from the lithospheric mantle.The above geochemical characteristics indicate that diabase in Huoluotai area originated from a lithospheric mantle source metasomatized by fluids derived from subducted slabs.Combined with previous research, it is concluded that the formation of diabase in Huoluotai area in northern segment of Erguna Block, Da Hinggan Ling (Mts.) is closely related to the rollback process of the Paleo-Pacific Plate.

Comprehensive research involving quantitative restoration of paleo-geotherm，paleo-geomorphology，sedimentary environment，and geological events were conducted to study the formation environment and genesis of hydrocarbon-rich shales in the Qingshankou Formation of northern Songliao Basin. The results show that the Ro of the hydrocarbon-rich shales in the Qingshankou Formation of Songliao Basin mainly ranges from 0.75% to 1.60%，with a high content of free hydrocarbons，mainly from 4 to 12 mg/g，formed under a high-temperature thermal basin background with a paleo-geothermal gradient of 50 to 70 ℃/km. Under the background of extensional geodynamics and thermal subsidence，shale layers controlled by densely fractured normal fault zones were formed. The paleo-geomorphology，characterized by two depressions and a protrusion，provided a conducive environment for the formation and evolution of these shales. The warm and humid climate of the lacustrine environment，along with magmatic hydrothermal fluids，laid the material foundation for the proliferation of algae，which was crucial for the development of thick layers of hydrocarbon-rich shales. The semi-deep lacustrine with oxygen deficiency，deep lake reduction，and strong reduction environment were conducive to the burial of organic matter. Comprehensive analysis indicates that the coupling effects of tectonics，lacustrine sedimentation，and paleo-geothermal conditions provided the tectonic background and thermodynamic conditions of hydrocarbon-rich shales. The warm and humid climate，anoxic environment，and nutrients brought by volcanic hydrothermal fluids are important reasons for the formation of hydrocarbon-rich shales.

To investigate the magmatic activity and tectonic evolution of Late Triassic⁃⁃Early Jurassic in south⁃ ern Xiao Hinggan Ling (Mts. ), and to identify its petrogenesis, formation time and tectonic setting, petrology, geochemistry and isotopic chronology of Late Triassic⁃⁃Early Jurassic monzogranites and syenogranites in Xiao Hing⁃ gan Ling (Mts. ) have been studied. The results show that the zircons of monzogranites and syenogranites are mag⁃ matic zircons with obvious magmatic oscillations and growth belts. The LA⁃⁃MC⁃⁃ICP MS zircons have U⁃⁃Pb dates of (202. 5 ± 1. 9) Ma and (191. 5 ± 1. 4) Ma, respectively, being Late Triassic to Early Jurassic. The geochemical characteristics show that the rocks are high silicon, rich potassium, rich alkali and low sodium, which is a I⁃⁃type granite of aluminous high potassium calc⁃alkaline series. Enrichment of Rb, K, Th, Hf, and deficit of Ba, Sr, Ti, Nb, P. Light rare earth elements are more abundant than heavy rare earth elements with an obvious negative anomaly (δEu = 0. 37 ~ 0. 58). Based on regional correlation and comprehensive study, it is preliminarily concluded thatthe tectonic setting of the granites in southern Xiao Hinggan Ling (Mts. ) is an active continental margin environ⁃ ment formed by the subduction of the paleo⁃⁃Pacific plate to Eurasia. 

Volcanic eruptions are often triggered by magmatic activities within the Earth’s crust. Monitoring the surface deformation in volcanic regions can effectively infer the state of underlying magma. To monitor the surface deformation of the volcanic areas，Sakurajima Volcano in Japan was selected for a detailed study. We applied the SBAS-InSAR technique to process 75 Sentinel-1A images from 2019 to 2021. The results show that Sakurajima Volcano is in a relatively active phase，predominantly characterized by subsidence during the monitoring period，with an average deformation rate of -10.05 mm/a. The most significant subsidence was observed at the central zone of the volcano，amounting to a cumulative deformation of -62.72 mm. This area also exhibited pronounced seasonal variations. The uplift occurred mainly in the peripheral area of the volcano，with the maximum uplift occurring on the southeast side of Sakurajima，with a cumulative uplift of 108.71 mm during the monitoring period.

Songliao Basin is one of the main basins for unconventional oil and gas exploration and development in China.The 1st and the lower part of the 2nd members of the Upper Cretaceous Qingshankou Formation are key focus layers for shale oil exploration.The research on the unclear sedimentary facies division and distribution issues of these layers in Changling Sag is beneficial for providing geological basis for shale oil exploration and selection in study area.Based on the drilling core, logging, and geochemical data of the 1st and the lower part of the 2nd members of the Qingshankou Formation in the Changling Sag of the Songliao Basin, and combining with the research results of the previous researchers, this paper conducts a detailed study of the sedimentary facies of the target layers in the study area from the aspects of lithofacies, sedimentary structure, and logging.The target strata in study area are divided into two sedimentary facies, the lake and delta facies, and four sedimentary subfacies including delta front, front delta subfacies, semi-deep lake and deep-lake subfacies.Among them, the front delta and semi-deep lake subfacies are advantageous sedimentary facies for shale oil exploration and development.The transgressive systems tract mainly develops delta front and front delta subfacies.Vertically, the two subfacies gradually slow down from bottom to top.Horizontally, the two subfacies gradually decrease towards the edge of the basin.The high water level systems tract mainly develops semi-deep lakes and deep-lake subfacies.Vertically, the two subfacies have a large thickness.Horizontally, the two subfacies extend to the center of the basin.The regressive systems tract mainly develops delta front, front delta, and semi-deep lake subfacies.Vertically, the semi-deep lake subfacies gradually slow down from bottom to top, while the thickness of the delta front and front delta subfacies gradually expands.Horizontally, the semi-deep lake subfacies decrease towards the center of the basin, while the delta front and front delta subfacies gradually extend towards the center of the basin.The dominant sedimentary facies zones mainly develop in late transgressive system tract and early regressive system tract.

Dachebeigou--Fu􀆳erling area is an important gold deposit distribution area, which located in the north of Jiapigou gold deposit mining area in Jilin Province, and several gold and antimony minerals such as Xingfu and Datudingzi have been discovered, indicating a certain prospecting potential. Based on the detailed study of metallogenic geological background and typical deposit characteristics of gold deposits in Dachebeigou -- Fu􀆳erling area of Jilin Province, the authors systematically summarized the prediction factors of regional gold deposits, established a regional prediction model for gold deposits, and delineated the minimum prediction areas with prospecting potential to provide a basis for the further deployment of exploration work. The evidence weight method was used to carry out the prediction of gold ore by “ mineral resources evaluation system” ( MRAS) software, and on the basis of the contour map and color block map, the delineation of the minimum prediction area was carried out according to the principle of minimum area has maximum minerality and minimum ore leakage rate, and the predicted gold resources were estimated by using the geological volume parameter method. In this work, a total of 13 minimum prediction areas of gold deposit were delineated, including 5, 6 and 2 minimum prediction areas of class A, B and C, respectively, and the estimated predicted resources of gold deposit were 36 295. 24 kg, of which the predicted resources of gold deposit within 500 m were 21 604. 31 kg and the predicted resources of 500 m to 1 000 m were 14 690. 93 kg. It is recommended to deploy investigation and evaluation work in the minimum prediction areas of class A, such as Zhilin, Datudingzi, Erdaodianzi, Beishan, Sidaogou and Xingfutun through the comprehensive evaluation of geological condition, geophysical and geochemical anomalies, resource potential and prospecting prospects, in order to explore new mineral areas and achieve new breakthroughs in gold prospecting.

To analyze the petrological characteristics, grain size distribution characteristics, sedimentary facies types and spatial distribution regularity of the Lower Karamay Formation in Block Si 1, Karamay Oilfield, Well D16 is selected as the standard well in the study area, and its drilling cores are used as the main data source for observation and experiments. Core observation, rock mineral thin section identification and sieve analysis are used to obtain petrological data such as colors, lithologies, sedimentary structure and texture, rock mineral composition and contents, and grain size distribution statistics of the Lower Karamay Formation reservoir in Block Si 1. The sedimentary facies types of the Lower Karamay Formation in Block Si 1 are identified based on sedimentary facies markers such as core colors, lithologic assemblages, structure and texture, grain size probability accumulation curves, C-M diagram, and structural parameter scatter plots. At the same time, combined with the geophysical data of more than 100 wells in the study area, the method of well logging is used to radiate the sedimentary facies model of the D16 standard well to other wells in the study area. By pulling the well-connected profile, the distribution regularity of sedimentary microfacies and sand bodies on the profile are analyzed. According to the thickness contour map of sandstone, the distribution regularities of sedimentary microfacies and sand bodies on the plane are analyzed. The results show that the core colors of Well D16 are brown, light brown, light gray and gray-green, and the lithologies are divided into unequal-grained sandstone, medium-fine sandstone, argillaceous siltstone, silty mudstone and mudstone according to the grain size, and the sandstone is divided into lithic sandstone, feldspathic lithic sandstone and lithic feldspathic sandstone according to the rock mineral types. The roundness is sub-angular to sub-rounded, the sorting is medium to poor. Massive bedding and tabular cross-bedding are developed, the contact relationships of particles are mainly point-line contact, and the pores are mainly residual intergranular pores. The probability accumulation curves of grain size are two-stage or four-stage types, the C-M diagram has the characteristics of traction flow, and the points of the structural parameter scatter plots are concentrated in the delta plain and front interval. The sedimentary environment of the Lower Karamay Formation reservoir in Block Si 1 is shallow,weakly oxidized to weakly reduced. Two sedimentary subfacies, the braided river delta front and the shallow lake,and four sedimentary microfacies, including the subaqueous distributary channel, the subaqueous interdistributary,the estuarine dam and the coastal shallow lake mud, are identified. The main reservoir sand bodies of the Lower Karamay Formation are subaqueous distributary channel sand bodies, which are distributed in lens-shaped and layered forms on the cross section and in strip-shaped and sheet-shaped forms on the plane. 

The timing of the final closure of the Paleo-Asian Ocean is one of the controversial issues in the field of geoscience.The central Jilin Province, which was controlled by the evolution of the Paleo-Asian tectonic regime during the Paleozoic, is an ideal place to resolve the above issue.The authors conducted systematic zircon U-Pb geochronological and geochemical studies on lithic sandstones and silty slates from Yangjiagou Formation in the Dakouqin area, central Jilin Province, and determined the deposition time and provenance characteristics of Yangjiagou Formation.The maximum depositional age of the formation can be constrained by the youngest weighted average age of detrital zircons, and therefore the lower depositional ages of the two lithic sandstones samples (PM001-38-TW1 and PM001-135-TW1) from Yangjiagou Formation were determined to be (255 ± 5) Ma and (251 ±2) Ma, which are consistent to the Permian and Triassic boundary (251.902 ±0.024) Ma.Combined with the ages of zircons that captured from the surrounding Late Triassic monzogranite dated (235-227) Ma, and the timing of the monzogranite aged (232 ±2) Ma which intruded in, the Yangjiagou Formation in the study area would deposit during the Late Permian.Whole rock major and trace element geochemical data of the lithic sandstones and silty slates from Yangjiagou Formation indicate that w (SiO2) ranges from 65.13% to 70.73%, w (Al2O3) form 14.75% to 17.29%, w (K2O) form 2.43% to 3.87%, w (Na2O) form 1.59% to 3.26%, and the ratio of K2O/ Na2O is from 0.75 to 2.34.The light rare earth elements are relatively enriched, while the heavy rare earth elements are depleted, with LREE/ HREE and Eu/ Eu∗ ratios of 6.98-9.09 and 0.56-0.70, respectively.Based on the CIA-ICV diagram, the source composition discrimination diagram and the tectonic setting discrimination diagram, the sedimentary provenance of Yangjiagou Formation has experienced a relatively moderate weathering with a high maturity.The Yangjiagou Formation whose source rocks are mainly felsic, were deposited in active continental margin or continental island arc.Detrital zircon age distributions of Yangjiagou Formation can be divided into five groups: Paleoproterozoic (1 819- 1 785 Ma), Meso-Neoproterozoic (1 491-561 Ma), Cambrian-Carboniferous (522-301 Ma), Early and Middle Permian (295-259 Ma), and Late Permian to Middle Triassic (258-238 Ma).Based on previous studies of regional magmatism, Yangjiagou Formation has bidirectional provenance characteristics (North China Plate and Xing􀆳an-Mongolian Orogenic Belt).The provenance attribute and paleontological evidence of Yangjiagou Formation show a tectonic transition from collisional orogeny to a stable tectonic environment.Combined with the characteristics of magmatism in the study area, the final closure of the Paleo-Asian Ocean in central Jilin Province is considered to happen in the Late Permian-Middle Triassic.

To address the safety hazards associated with hidden goafs in mines，the authors utilize an array of detection techniques，including geological radar，high-density resistivity，transient electromagnetism，seismic methods，controllable source audio magnetotellurics，and audio magnetotellurics. Focusing on the Bayan Aobao area in the Sunite Right Banner of the Inner Mongolia Autonomous Region，this research specifically targets the optimization of goaf detection methods for fluorite deposits. By integrating the geological and physical characteristics of the deposit with the results of geophysical exploration，it was determined that a combined approach of geological radar and high-density resistivity methods is highly effective in detecting the distribution of hidden goafs. This combination successfully identified the spatial distribution of hidden goafs up to a depth of 90 m in the study area. The accuracy and feasibility of this detection methodology were further corroborated by drilling verification and 3D laser scanning.

Geological hazard risk evaluation plays a significant guiding role in disaster prevention and mitigation.Focusing on the issues of frequent and severe geological hazards in Lüchun County, this study conducts a geological hazard risk evaluation to provide scientific support for disaster prevention planning and risk management in Lüchun County.Taking Lüchun County in Yunnan Province as the study area, grid unit is selected as the evaluation unit, and nine evaluation factors are chosen: elevation, slope, aspect, distance to faults, distance to rivers,engineering geological rock groups, geomorphological types, curvature, and land use types.Utilizing the spatial analysis function of geographic information system, the weighted information value model, which combines the information value model and the analytic hierarchy process, is applied to evaluate the susceptibility of collapse and landslide geological hazards in Lüchun County.The monthly average rainfall in Lüchun County is selected as the triggering factor for geological hazard evaluation of landslides and collapses in the study area.Three disaster bearing factors: population density, the number of threatened people, and land use types, are selected to complete the vulnerability evaluation.The hazard index and vulnerability index are multiplied then to produce the risk evaluation of collapse and landslide geological hazards.The results show that Lüchun County can be divided into four risk levels:low, medium, high and extremely high, which accounted for 12.84%, 46.01%, 38.28% and 2.87% of the county area, respectively.The low risk areas are mainly located in the middle of Banpo Township, the north of Qimaba Township, the north of Daxing Town and the south of Gekui Township.The middle risk areas are mainly distributed in the north of Daheishan Town, the west of Dashuigou Township, the middle and south of Qimaba Township, the middle of Gekui Township and the southwest of Pinghe Town.High and extremely high risk areas are mainly distributed around Lüchun County and Daxing Town, Niukong Town, Sanmeng Township, Pinghe Town,and the middle of Dashuigou Township.The results of geological hazards risk evaluation obtained in this paper are in good agreement with the actual investigation.

To elucidate the sedimentary characteristics and reservoir development patterns of the near source sandy braided river delta in the Laizhou Bay Sag of the Bohai Bay Basin，an analysis was conducted using seismic，drilling，logging data，core observations，and grain size analysis. This study summarized the sedimentary characteristics of the upper part of the 3rd member of the Shahejie Formation (width=32,height=17,dpi=110) in the K Oilfield. The results indicate that in thewidth=32,height=17,dpi=110of the K Oilfield, three subfacies can be identified: the braided river delta plain, braided river delta front, and the braided river front delta. Six sedimentary microfacies are further distinguished: braided river channels, alluvial plains, underwater distributary channels, mouth bars, sheet sands, and underwater interdistributary channels. These microfacies exhibit distinct particle size distribution characteristics. A complete set of transgressive and regressive cycles is evident inwidth=32,height=17,dpi=110. Initially, sedimentation was dominated by underwater distributary channels with sand reservoir thicknesses ranging from 4 to 9 m. Mouth bars developed at the channel ends with reservoir thicknesses of 3 to 8 m. The distributary channels, having the widest planar distribution, constitute the key reservoirs in the area. Subsequently, as the lake level gradually rose, the extent of mouth bar development peaked. After reaching the maximum flooding surface, the lake level slowly declined, leading to the development of the braided river delta plain subfacies at the top ofwidth=32,height=17,dpi=110, where the sandstone thickness reduced to 2 to 5 m.

 As urbanization continues to accelerate, it is difficult to acquire real-time data on potential pavement
 collapse hazards utilizing traditional methods. At present, efficiently monitoring pavement collapse has become a key
 challenge in the field of pavement safety. For this problem, the authors propose a method which combines time-series
 InSAR with wavelet transform. This method analyzes the change cycle of the subsidence point to obtain the deformation information, and extracts the temporal and spatial evolution characteristics of ground subsidence. For those areas
 with obvious spatial and temporal evolution characteristics, the accuracy of the InSAR results will be further verified
 by using the microtremor detection seismograph. We selected 52 Sentinel-1A images captured between March 2022
 and November 2023 to obtain the surface subsidence results in the central urban area of Changchun by the time-series
 InSAR method. The results showed that the maximum deformation rate was-30. 58 mm/ a, and the maximum cumu
lative subsidence was-73. 3 mm in the study area. A detailed analysis of the representative deformation area, Nanhu
 avenue, revealed a maximum deformation rate of- 28. 44 mm/ a, a maximum daily average deformation rate of-0. 93 mm/d, and a maximum cumulative subsidence of-56.4 mm. The analysis of significant subsidence points
 based on wavelet transform uncovered their subsidence evolution processes. The development of surface subsidence in
 severely affected areas was influenced by multiple periodic variations of different magnitudes and levels, with nested local
 cycles within these periodic time scales that affect the specific trends of subsidence development. Using microtremor
 detection seismograph to collect data from regions with obvious evolutionary characteristics, the authors generated a
 geological profile of Nanhu avenue. According to the profile, significant subsidence points exhibited a phenomenon of
 slurry infiltration. This further validated the accuracy of the subsidence monitoring results. Finally, by comparing the
 actual pavement collapse incident in the Nanhu avenue metro construction area to the subsidence results monitored in this
 study, the feasibility and accuracy of the proposed method in practical applications were validated.

In order to explore the electromagnetic wave detection response characteristics of shallow under-
ground buried targets in a specific medium and meet the urgent needs of urban underground pipeline management
and unknown target detection, a high-performance antenna for ground penetrating radar system was innovatively
designed based on the in-depth analysis of the rectangular waveguide theory. Firstly, according to the propagation
characteristics of electromagnetic waves in the rectangular waveguide, the basic model of the antenna is constructed,
the cut-off frequency of the antenna is calculated, and the monopole probe is selected as the effective excitation
source. Secondly, the high frequency structure simulator (HFSS) of Ansys electronics desktop (AEDT) simulation
platform was used to carry out numerical simulation and optimization of the antenna model. By in-depth analysis of
the influence of the installation position and insertion depth of the monopole probe in the rectangular waveguide on
the transmission characteristics of the antenna, the S11 reflection coefficient, voltage standing wave ratio (VSWR) and
radiation pattern of the antenna were accurately adjusted. Finally, in order to verify the accuracy of the theoretical
analysis and simulation results, the antenna was fabricated with aluminum foil board material, and the ground
penetrating radar system was built with vector network analyzer (VNA) in a controlled sand trough environment for
field testing, and the detection height of the antenna was adjusted to cover underground targets at different depths.
Experimental results show that the antenna can stably and accurately identify all preset targets. The ground penetrating
radar antenna based on rectangular waveguide shows excellent directionality, ultra-wideband and high resolution
after finely adjusting the insertion depth of the probe and the distance between the probe and the short-circuit
surface of the rectangular waveguide to achieve the best matching of antenna impedance, which provides an efficient
and accurate new tool for urban underground space management and unknown target detection.

To address the challenge of long-duration data collection difficulty in urban geophysical exploration resulted from regulatory restrictions on exploration sites，the authors utilize ultra-short-duration passive source noise data. By employing the phase-weighted stacking of cross-correlation functions，dispersion curves are extracted. The fundamental mode dispersion curves are then inverted to obtain a one-dimensional S-wave velocity profile. Utilizing this profile as an initial model，a second-stage inversion is conducted，which reveals the presence of underground cavities. The results of this study demonstrate the feasibility of using ultra-short-duration passive source surface-wave imaging for cavity detection.

During Late Paleozoic to Early Mesozoic, it was found that the tectonic evolutionary history of the Zhangguangcai Ling (Mts. ) in Northeast China can be divided into 3 stages: ① Late Permian⁃⁃Middle Triassic (266⁃⁃234 Ma), the westward subduction of Heilongjiang Ocean formed I⁃⁃type grantic rocks; ② Late Triassic⁃⁃ Early Jurassic (224⁃⁃194 Ma), the Jiamusi⁃⁃Khanka Block and the Songliao Block collided after the closure of Hei⁃ longjiang Ocean, forming I⁃⁃type with a few A⁃⁃type granitic rocks; ③ Early⁃⁃Middle Jurassic (194⁃⁃163 Ma), A2 ⁃⁃ type and I⁃⁃type granites were developed under the complex influence of the extensional environment after the colli⁃ sion of the two blocks and the westward subduction of the Paleo⁃⁃Pacific Ocean. Combined with new evolution on the Heilongjiang Complex and the Nadanhada Terrane, the authors consider that the transition between the Paleo⁃⁃ Asian Ocean and the Paleo⁃⁃Pacific Ocean in eastern Eurasia occurred in the Late Triassic⁃⁃Early Jurassic, and the Heilongjiang Ocean was an important hinge linking up the tectonic transition between these two domains. 

To systematically understand the sequence boundary identification and sedimentary environment evolution in the ultra⁃deep water area of the Baiyun Sag, Pearl River Mouth Basin, the authors conducted a compre⁃ hensive analysis using trace and major element data from the carbonate rock section of the Late Oligocene Zhuhai Formation to Early Miocene Zhujiang Formation of the drilled Well A1 in Baiyun Sag. The results show: ①Three third⁃order sequence boundaries of SB24. 80, SB23. 03 and SB21. 00 were identified through the variation charac⁃ teristics of parameters such as concentrations of Pb, Zn, Rb, Al 2O3 , Fe2O3 , and Th / U ratio. ②Based on the var⁃ iability of Sr/ Ba, V/ Ni, Sr/ Cu, Al 2O3 / MgO, and MgO/ CaO ratios, it is confirmed that the sample section deposi⁃ ted mainly in a sedimentary environment characterized by arid climate and relative sea⁃level rise. ③Ratios of V/ Cr, Ni / Co, V/ (V + Ni) suggest that the carbonate rocks in Well A1 are mainly developed in ancient marine wa⁃ ter bodies of oxidizing environments, with shallow water bodies. In the later stage, the water level tended to rise to⁃wards hypoxic conditions, and the development of carbonate rocks was terminated by “drowning”. 

In order to investigate the diversity and complexity of sedimentary reservoirs, to clarify the sedimentary characteristics and sand body development rules of the Cretaceous Shushanhe Formation (K1s) in Tahe Oilfield, Tarim Basin, and to analyze the relationship between sedimentary microfacies and reservoir sand body distribution,core analysis and logging analysis methods were used to identify lithological markers, mainly including rock color,composition, sedimentary texture, sedimentary structure, rock type and lithological associations, and to identify logging markers, including qualitative logging curve characteristics and quantitative logging data characteristics.Adopting systematic sedimentological analysis methods, mainly geological methods, the authors summarized lithology and logging sedimentary facies markers, and established sedimentary microfacies classification standards, and analyzed sedimentary facies types and their evolutionary characteristics vertically and on the profile through the study of single-well facies and profile facies.We also analyzed the plane characteristics of sedimentary microfacies by using ratio of sand to stratum, and the distribution pattern of sandstone in the region by using thickness of sand body.Based on the core and logging data, a sedimentary microfacies division standard was established, one singlewell sedimentary facies diagram and two horizontal and vertical profile facies diagrams were drawn; while the sedimentary microfacies plane and sand body distribution of four small layers were completed, and the regional braided river delta front sedimentary model was summarized.The Upper Member of Shushanhe Formation (K1s3) in TP12 -8 well area belongs to the shallow water gentle slope braided river delta front sedimentation system, which identifies three sedimentary microfacies of the subaqueous distributary channel, the subaqueous interdistributary channel and the channel edge, and the provenances come from the southern area of Tuofutai.Because the sedimentary environment is a large oxidized wide shallow lake basin, it has unique sedimentary characteristics.Different from the general subaqueous deposition, the color of sediments in the TP12-8 well area is oxidized, such as brown.Sand body is stacking developed, mainly fine sandstone, accounting for about 75% of the total area on the plane, and the thickness of the sand body can reach 1.4-23.9 m.The subaqueous distributary channel is the main sedimentary face in the study area, and the mouth bar does not develop.After the channel enters the lake, it continues to extend,running through the whole study area in a strip shape, with a width of 1.5-9.0 km.

To study imaging optimizing algorithms for low signal-noise rate (SNR) seismic data in irregular topography, an effective coherence constraint noise suppression method is established according to the obvious difference in coherence characteristics between noise and effective reflected signals, which can provide theoretical and technical support for practical applications of the imaging in irregular topography.In order to solve the problem of conventional imaging of low signal-to-noise ratio seismic data in irregular topography, a coherence constraint Gaussian beam migration method for irregular topography is proposed in this paper.The elevational correction of
time-shift eliminates the inaccuracy of beam decomposition caused by irregular topography.Horizontal projection equivalent discrete interval (HPEDI) for beam center and receiver location is designed to solve the drawback of unbalance of imaging amplitude.About the coherence constraint, a new stable complex domain weighted coherence spectrum computing method is proposed, and the threshold extraction and exponential strengthening methods for effective reflection signal are designed to achieve the effective suppression of random noise and incoherent false imaging.Numerical experiments of 2 synthetic data examples and 2 measured data examples are applied to validate the effectiveness of the proposed methods in noise and false image suppression.The proposed HPEDI method can achieve significant image optimization in amplitude equalization and arc false image suppression for the synthesized data in irregular topography.The coherence spectrum of real measured data verifies that the weighted coherence spectrum is smoother and more stable than the conventional coherence spectrum.Most of the arc false images of the synthesized data in a layered model are suppressed by using the threshold of coherence spectrum.The irregular real measured low signal-to-noise ratio data prove that the proposed coherence constraint method suppresses random noise obviously.The proposed coherence constraint migration imaging method can effectively suppress the noise and false imaging without coherence characteristics in the imaging process, and can significantly improve the imaging effect. 

Rational development and utilization of cultivated land reserve resources are essential for ensuring China’s food security, while suitability evaluation is the prerequisite and foundation.By scientifically assessing the development suitability of these resources, it provides a scientific basis for rational allocation and sustainable utilization of regional land resources.The authors take Da’an City of Jilin Province as the study area and develop a comprehensive suitability evaluation system from natural, social, and ecological perspectives.Using methods such as AHP (analytic hierarchy process), landscape pattern indices, and composite indices, the authors conduct a systematic analysis to reveal quantity, quality, and spatial distribution characteristics of development suitability levels of cultivated land reserve resources in Da’an, and propose corresponding development and utilization strategies.The research results indicate that: the development suitability of cultivated land reserve resources in Da’an City can be categorized into four levels: highly suitable, moderately suitable, marginally suitable, and unsuitable, accounting for 26.64%, 38.83%, 25.08%, and 9.44% of total area of cultivated land reserve resources, respectively.Development suitability levels gradually decrease from central part of Da’an City toward northeast and southwest.Highly suitable and moderately suitable development areas are mainly concentrated in Xinping’an Town and Haituo Township, while unsuitable development areas are mainly concentrated in Longzhao Town in southwestern part of the city.Land use types are primarily saline-alkali land and other grasslands, accounting for 99.67% of total area of cultivated land reserve resources in city.The highly suitable development areas for saline-alkali land are distributed in northwest and southeast, while the highly suitable development areas for other grasslands are concentrated in the central and western parts.Spatial distribution of development suitability levels for cultivated land reserve resources in Da’an City shows significant variation, with moderately suitable development areas being the most prevalent.Development and utilization strategies for cultivated land reserve resources should be tailored to local conditions.Saline-alkali land development should focus on water resource management and soil salinization amelioration measures, while development of other grasslands should carefully control development intensity to maintain regional ecological balance.

 In order to explore the distribution of high quality reservoirs within the Cretaceous volcanic edifice in the M region in the eastern uplift zone of the Santos Basin, Brazil, volcanic lithology, lithofacies, stages, types of edifice and their relationship with reservoirs were studied in the Cretaceous volcanic strata in the M region, based on the drilling cores, conventional logging curves, three-dimensional seismic data and logging physical properties,with the methods of volcanic petrology and volcanic stratigraphy.The results show that four types of volcanic edifice were identified in the M region, including onshore basaltic tabular lava edifice, onshore basaltic fill-type lava edifice, subaqueous basaltic thick-layer lava edifice, and subaqueous basaltic compound lava edifice.Furthermore, the volcanic rocks in the M region were divided into five eruption stages, of which eruption stage 2 (E2) is characterized by the deposition of onshore basaltic tabular lava edifice, stage 3 (E3) consists of the subaqueous basaltic thick-layer lava edifice and subaqueous basaltic compound lava edifice, stage 4 (E4) comprises merely subaqueous basaltic compound lava edifice, and stage 5 (E5) is composed of onshore basaltic fill-type lava edifice.Additionally, the reservoir physical properties vary among four types of volcanic edifices, with the subaqueous basaltic compound lava edifice exhibiting the best properties, subaqueous basaltic thick-layer lava edifice being moderate, and the onshore basaltic tabular lava edifice and onshore basaltic fill-type lava edifice demonstrating the worst properties.Based on these findings, it is considered that in the M region, the reservoir associated with E4 featuring subaqueous basaltic compound lava edifice is the best, the reservoir of E3 comprising subaqueous basaltic thick-layer lava edifice and subaqueous basaltic compound lava edifice ranks second, the reservoirs of E2 and E5 which involve onshore basaltic tabular lava edifice and onshore basaltic fill-type lava edifice are considered the least favorable.Therefore,volcanic rocks from E3 and E4 can be targeted as key areas for subsequent oil and gas exploration in the study area.

 The Chaganhua Subsag, one of the subsags in the Changling Fault Depression, Songliao Basin, is divided into two parts: the northern and the southern. The spatial relationships between the source rocks and reservoir rocks and the interstitial physical properties of the volcanic rock hydrocarbon reservoirs are similar in the northern and southern parts. However, exploration and development reveal that the distribution and activity periods of the faults in the southern and northern parts of the subsag are different, and volcanic rock hydrocarbon reservoirs in the northern part of the subsag are more than those in the southern part. In this study, seismic interpretation data were used to statistically analyze the occurrence and activity period of the main active faults in the Chaganhua Subsag,2D hydrocarbon accumulation simulations were processed with key well-crossing profiles on the basis of the source rock burial history. The matching relationships between the activity periods of the main active faults and the hydrocarbon charging periods in the southern and northern parts of the Chaganhua Subsag were compared. The controlling effects of fault activity on hydrocarbon migration and accumulation, and the causes of the differences in the distributions of volcanic rock reservoirs in the northern and southern parts of the subsag were analyzed. The results revealed two hydrocarbon charging periods of volcanic reservoir in the Chaganhua Subsag. One period was the Early Cretaceous Denglouku stage, and the other was from the end of the Early Cretaceous Quantou stage to the Late Cretaceous Qingshankou stage. Three levels of faults were developed in the Mesozoic strata under an extensional structural environment. The secondary faults were the important factors in hydrocarbon migration and accumulation.Many secondary faults developed with long activity period in the northern part of the Chaganhua Subsag. Their activity period was as long as from the Early Cretaceous Huoshiling stage to the end of the Quantou stage or even to the end of the Late Cretaceous Qingshankou stage. The hydrocarbon charging period as well matched the fault activity period. The secondary faults in the northern part of the subsag performed the main migration paths, in the volcanic hydrocarbon accumulations under the coordinating of unconformities. In the southern part of the subsag,the secondary faults were less developed with short activity periods from the Early Cretaceous Shahezi stage to the Denglouku stage. These faults were bad for matching the hydrocarbon charging periods, and had little control effects on hydrocarbon accumulation in the southern part of the subsag, and played a limited role in hydrocarbon migration. Some of these faults with long activity periods could be beneficial for hydrocarbon migration with the assistance of advantageous volcanic facies belts. The fault activity periods and their matching relationships to hydrocarbon charging periods are the main reasons for the differences in volcanic rock hydrocarbon reservoirs between the southern and northern parts of the Chaganhua Subsag.

The Baoligaomiao Formation，located in the Arshan area of the Da Hinggan Ling(Mts.)，comprises a continental sedimentary-volcanic rock series，predominantly formed of sedimentary clastic rocks and andesites，which have undergone regional metamorphism and have been converted into the low greenschist facies. This study focuses on the zircon U-Pb dating and geochemical analysis of the low-grade metamorphic rocks of Baoligao-miao Formation. By integrating lithologic petrographosed and metamorphic deformation characteristics，the research aims to reconstruct the protolith structure and explore the sedimentary setting. The results indicate that the LA-ICP-MS zircon U-Pb age of the metamorphic andesites in the Arshan area is approximately (312.1±1.2)Ma，belonging to the Late Carboniferous and Early Permian periods，and it is identified as part of Baoligaomiao Formation. The protolith assemblage of Baoligaomiao Formation in the Arshan area is a typical terrigenous intermediate-acidic volcano-sedimentary lacustrine facies. The sedimentary tectonic environment is the intra-arc basin of the active continental margin，which is consistent with the tectonic environment of the Late Carboniferous-Early Permian in Erlian-Hegenshan ophiolite-accretionary complex.

In the northern segment of the Da Hinggan Ling(Mts.)，Late Mesozoic granites are highly deve-loped. However，the volcanic activity periods，rock compositions，and petrogenetic mechanism in this area have been controversial in the field of earth sciences. The authors systematically conducted zircon U--Pb isotope geochronological and whole-rock elemental composition studies on the medium-fine grained granodio-rite in the Huma area of the northern segment of the Da Hinggan Ling(Mts.)，and aimed to investigate rock genesis and magmatic source regions，analyze the tectonic setting of rock formation，and attempt to constrain the timing of the closure of the Mongol--Okhotsk Ocean. The research results indicate that the crystallization of the granodiorite is (149.9±1.7 Ma)，which is the Late Jurassic. The granodiorite is rich in Si and Al，but poor in Mg，Y and Yb (w(Y)≤18×10-6, w(Yb)≤1.9×10-6), has high Sr content (w(Sr)>400×10-6) and A/CNK of 1.01-1.15，belonging to the high-K calc-alkaline rock series. It is relatively enriched in Rb，Ba，K，La，Ce and Sr elements，and depleted in Ta，Nb，P，Ti，Y，Yb and Lu elements，with a weak positive Eu anomaly. It belongs to the “C” type Adakite. Combined with the regional magmatic zircon Nd isotopic composition characteristics，the data indicate that the magma originated from the partial melting of accretionary lower crustal amphibolite-facies material during the Late Neoproterozoic to Phanerozoic. Combining geochronological，geochemical characteristics，and regional tectonic evolution，it is suggested that the Late Jurassic granodiorite in the Huma area of the northern segment of the Da Hinggan Ling(Mts.) formed in a post-collision uplift tectonic environment and is closely related to the closure of the Mongol--Okhotsk Ocean.

When a water-bearing karst structure exists，the temperature field of shallow strata will change. The shallow temperature measurement method can quickly and easily obtain shallow geothermal data，and the distribution of karst structures can be inferred through temperature differences. To study the feasibility of detecting karst conduit structures using shallow temperature measurement technology in a site in Panzhou City，Guizhou Province，and its surrounding areas，the numerical simulation methods were used. The results show that different burial depths of the structure significantly change the temperatures of shallow strata. For a single karst conduit structure (with an equivalent diameter of 0.5 m and water temperature of 12 ℃)，the maximum detectable depth is approximately 66 m. When the fluid temperature inside the conduit is 12 ℃，an increase in the effective flow cross-sectional area of the karst conduit structure will lower the temperature of the shallow strata. When the equivalent diameter changes within the range of 0.1 to 1.0 m，the change in the temperature of the strata at 2.0 m is within 0.02 ℃，making it difficult to identify changes in the effective flow cross-sectional area of karst structures using shallow temperature measurement. The change in fluid temperatures within a certain range (12 to 18 ℃)will alter the temperatures of the shallow strata，especially the impact of low-temperature fluids.

To investigate the current water quality of potable groundwater sources，this paper utilizes methods such as mathematical statistics，Piper diagrams，Gibbs diagrams，and environmental background value statistics to study the hydrochemical characteristics and formation mechanism of groundwater drinking sources in Zhongshan City and its surroundings. The results show that the groundwater in the study area is weakly acidic and low in mineralization，with Na+ and width=37,height=17,dpi=110 being the main ions. The hydrochemical type is predominantly HCO3-Na·Ca. The chemical composition of the water is influenced by the combined effects of atmospheric precipitation and rock weathering，with a strong cation exchange reaction. The main reasons for the decrease in groundwater pH value are the long-term abundance of acid rain，the poor buffering capacity of the soil and aquifer in the vadose zone against acid deposition，and the hydrolysis of alkaline earth metals，CO2 and carbonates.

To analyze the geothermal geological characteristics and formation model of the sandstone geothermal reservoirs in the northwestern plain of Shandong，the authors used a combination of data collection and experimental testing methods to study the characteristics of geothermal reservoirs，geothermal gradient，hydrochemistry，and dynamic changes in water levels. The results show that the sandstone geothermal reservoirs in the northwestern plain of Shandong are mainly of the Neogene Guantao Formation and Paleogene Dongying Formation，with the deepest burial depth of the reservoir top and maximum formation thickness located in Linyi County，Liaocheng. The geothermal gradient is generally below 3.4 ℃/100 m，except in the uplifted area of Pingyuan County，where the gradient exceeds 4.0 ℃/100 m. The geothermal water is primarily of the Cl-Na type，characterized by an enrichment of Na+，K+，and Cl- ions. The geothermal water temperature ranges from 54.4 to 85.9 ℃，with the highest reservoir temperatures observed in Linqing，Liaocheng. There is minimal hydraulic connectivity between the geothermal water in the sandstone reservoir and deep groundwater，and changes in geothermal water levels are mainly influenced by artificial extraction and recharge activities.

In order to study the importance of the spatial and temporal distribution characteristics of sea ice in the marine disaster warning, resource development and global climate change research, the authors use multi-tem- poral remote sensing data to extract and analyze the spatial distribution range and sea ice thickness information in Liaodong Bay of Bohai Sea during winter months based on the remote sensing inversion modeling of sea ice thickness. First, the sensitive wavebands that have a significant response to differences in sea ice thickness were screened based on the variance analysis method, and a sea ice thickness-sensitive band reflectance statistical correlation model was constructed based on the regression analysis method. The multi-temporal remote sensing data were used further to reflect the sea ice thickness in Bohai Sea and to analyze the spatial and temporal distribution characteristics of sea ice. Experimental results show that the red-light band data of Landsat satellites have high sensitivity in retrieving sea ice thickness, and the regression statistical model established on the red-light data has a linear fitting regression sum of squares as high as 0. 975 1, which indicates that the model has high accuracy and reliability. The result of Landsat red-light band data used for retrieval on the sea ice thickness and spatiotemporal distribution of sea ice in Liaodong Bay of Bohai Sea indicates that the sea ice begins in late December every year at Panjin and Yingkou in Bohai Sea, and reaches the thickest and largest distribution area by January. As the temperature gradually rises, sea ice gradually recedes in early February, and completely disappears by early March. In addition, the proportion of thin ice is generally high in each winter month, while that of thick ice is relatively low. The sea ice in Bohai Sea freezes earlier and thicker in higher latitude areas or closer to the coast, and retreats later. On the contrary, the ice in the low latitude areas freezes later and retreats earlier. 

In recent years，with the continuous popularization of geothermal energy and enhanced geothermal systems (EGS)，there has been an increase in the occurrence of induced microseismic events. To explore the mechanism of seismic activity and identify the potential risks of induced microseismicity in practical engineering，the authors took the hydraulic fracturing site in Haikou City，Hainan Province，as the study area. By collecting relevant geological and geophysical (gravity and magnetic)exploration data，a two-dimensional geological model was established，which was used to simulate and analyze the temporal and spatial evolution of the pore pressure and pore elasticity effects on the fault surface. Subsequently，an assessment of the risk of induced seismicity and a prediction of the magnitude of the seismicity were conducted. The results show that fluid injection in the study area will lead to changes in the stress on the nearby faults，which may cause minor fault activation phenomena，but the magnitude of the resulting earthquakes is low，resulting in a lower engineering risk.

Taking Mindoro Island in Philippines as the study area, and selecting ALOS PALSAR dual⁃polariza⁃ tion data (polarization mode of HH and HV polarization) as the source data, the authors used the maximum likeli⁃ hood classification method to classify the rock units and geological mapping in study area by extracting the backscat⁃ tering coefficients (Sigma0 HH and Sigma0 HV) and the polarization decomposition parameters (entropy, angle and anisotropy). With the inclusion of polarization decomposition parameters, the overall accuracy increased from 36. 706% to 65. 000% , comparing to the result using only backscattering coefficients. The F1 scores of the coastal marsh and coral reef exceeded 0. 80, and those of the gabbro and Mansalay Formation exceeded 0. 75. After adding polarization features, the rock unit boundaries were better extracted and increased separability of the Mansalay Forma⁃ tion and Mindoro metamorphic rocks from other rocks. Three polarization decomposition parameters compensate for the similarity of backscattering coefficients of multiple rock units and significantly improve the separability of rock units. It is shown that the combination of polarization decomposition parameters and backscattering coefficients of L⁃bandSAR data can improve the classification accuracy of rock units in vegetation⁃covered areas. 

Aiming at the challenge of effective signal loss in traditional methods of separated diffracted and reflected waves，a method using two-dimensional variational mode decomposition (2D-VMD)to separate diffracted and reflected waves of ground penetrating radar(GPR)data is proposed. After decomposing two-dimensional GPR data using 2D-VMD，intrinsic mode function (IMF)components and the F-K spectrum of each IMF can be obtained，which range from low-frequency and low-wave number to high-frequency and high-wave number. By analyzing the differences between the diffracted wave and the reflected wave in the frequency-wavenumber domain，the IMF components corresponding to diffracted and reflected waves are reconstructed separately，and the separated diffracted and reflected wave data are obtained. The processing results of numerical simulation and measured data show that，compared with traditional methods，this method can effectively separate diffracted waves and reflected waves without losing any effective signals.

Gejiu tin mine in Yunnan is a super-large polymetallic ore concentration area dominated by tincopper, altered vein-type ore bodies within rock masses have been identified in recent years. To clarify the orecontrolling conditions and metallogenic regularities of these intra-rock altered vein-type ore bodies and to provide theoretical support for exploring new prospecting targets around Laochang ore field, the authors carry out detailed field investigation and measurement of the known ore bodies in Fengliushan ore section within the western depression zone of Laochang ore field, Gejiu mining area and three levels (1 800 m, 1 700 m and 1 600 m) of the joints and fractures (including ore veins) exposed by the internal tunnels through the comprehensive analysis of mine data. Statistical analyses were conducted on the orientation and dip angles of different joint sets, their ore-controlling and ore-hosting characteristics, and their relationship with regional fault tectonics. The results show that there are three major groups of well-developed joints and fractures in Fengliushan ore section, including NE-, NW- and nearly EW-trending, with most dip angles ranging from 60° to 80°. These features like the fracture distribution patterns in Gejiu mining area. Interactions among fractures from different orientations form favorable “X-type” tectonic structures conducive to mineralization. Among these, the nearly EW-trending fractures are the most prominent and commonly host tourmaline-quartz veins or chalcopyrite-pyrite-cassiterite-scheelite mineralization veins, maybe the radius tensional joints and fractures formed in the process of emplacement-condensation of granitic rock mass. In contrast, the NE- and NW-trending fractures primarily represent late-stage mineralization-disrupting structures that postdate and damage earlier EW-trending ore-controlling ( ore-hosting) fractures. A total of 284 ore-bearing fractures were measured, predominantly oriented nearly EW-trending, indicating that nearly EW-trending joints serve as the primary ore-controlling structures.

To investigate the rare earth element (REE) fractionation patterns, grades, and their influencing factors in different ore blocks of the Bayan Obo REE-Nb-Fe symbiotic deposit, and to provide guidance for research on REE patterns and directional mineral processing at Bayan Obo, elemental mass fraction was conducted using inductively coupled plasma mass spectrometry on samples from different ore blocks of TK13-04 core in the main orebody. Results show that two distinct REE fractionation patterns exist in the main orebody. The REE fractionation pattern of the middle dolomite Fe-REE ores differ from that of the upper and lower dolomite REE ores. The former exhibits an “initial upward inclination followed by rightward inclination” characteristic with increasing from La to Nd and then decreasing from Nd to Lu. In contrast, the latter shows a “rightward inclination” pattern with gradually decreasing from La to Lu. The middle dolomite Fe-REE ores have a lower mass fraction of total REEs compared to the upper and lower dolomite REE ores. The total REE mass fraction is closely related to the degree of light-to-heavy REE (LREE-HREE) fractionation, the REE fractionation pattern, and the total iron (TFe) mass fraction. Higher degrees of LREE-HREE fractionation and higher La/ Nd ratios correlate with higher total REE mass fraction. When the TFe is below 20%, there is no definitive correlation between TFe and the REE mass fraction. However, when the TFe mass fraction exceeds 20%, the total REE mass fraction decreases signifi cantly. Compared to the average proportions of individual light REEs (LREEs) in the mining area, the proportion of Ce in the middle dolomite Fe-REE ore block of TK13-04 is significantly lower ( ~37%), while the proportion of Nd is significantly higher ( ~40. 7%), exceeding the proportion of Ce that is typically the dominant REE in the deposit. The proportion of La in the middle dolomite Fe-REE ore block is also reduced ( ~9%) and the proportions of Pr and Sm are increased. Therefore, the middle dolomite Fe-REE ore blocks hold greater potential for the utilization of Nd, Pr, and Sm elements. For the utilization of La and Ce, development of the upper and lower dolomite REE ore block would likely yield more substantial benefits.

To investigate the tectonic evolution of Paleo--Asian Ocean, the authors select Late Paleozoic intrusive rocks exposed in Bilihe area of central Inner Mongolia as objects, and constrain their formation ages, petrogenesis, magma sources and tectonic settings through petrographic, geochronological and geochemical analyses. Zircon U--Pb dating yields ages of (263. 7 ± 2. 8) Ma for the potassium feldspar granite and (273. 8 ± 1. 2) Ma for the granitic porphyry, indicating an Early --Middle Permian emplacement. Their εHf ( t) values range from - 8. 5 to 4. 0 and - 0. 4 to 2. 3, respectively. Geochemical data reveal both rock types exhibit high silica [w ( SiO2 ) = 61. 98%--70. 65% ] , alkali-riched [w (Na2O) = 2. 78%--2. 94% ] and potassium-eriched [w (K2O) = 3. 47%-- 3. 60% ] characteristics. The A / NK ratios vary from 1. 30 to 1. 75, A / CNK ratios vary from 0. 86 to 1. 10, and Rittmann indices vary from 2. 07 to 2. 53, the granite and porphyry are belonging to high-K calc-alkaline series, being classified as metaluminous to weakly peraluminous rocks. Both rocks display enrichment in light rare earth elements (LREEs) and large-ion lithophile elements ( LILEs: Cs, Rb, Ba, Th) , depletion in heavy rare earth elements (HREEs) and high-field-strength elements (HFSEs: Nb, P, Ti), along with weak Eu negative anomalies (δEu = 0. 62--0. 67 and 0. 49--0. 54). Moderately fractionated REE patterns [ (La / Yb) N = 8. 10--8. 30 and 6. 80-- 6. 92] with REE right-inclined chondrite-normalized curves suggest characteristics of volcanic arc granites. Th / La (avg = 0. 44) , Rb / Sr ( avg = 0. 65) and Th / Nb ( avg = 1. 35) ratios align with crustal compositions, indicating derivation from partial melting of crustal materials. The potassium feldspar granite exhibits broader εHf (t) variations and higher Mg values [w (MgO) = 3. 05%--3. 33% ] , implying mantle-derived influence. Integrated results suggest these rocks formed during the subduction of the Paleo --Asian Ocean beneath the North China Block. In Early--Middle Permian, the Paleo--Asian Ocean was not closed, and the northern margin of the North China Block situated in an active continental margin setting, marked by intense regional magmatism. 

Based on the cores, field sections, thin sections and organic geochemical data, the sedimentary facies characteristics of the Mesoproterozoic Hongshuizhuang Formation and the evaluation of source rocks were carried out. The results show that the Mesoproterozoic Hongshuizhuang Formation is mainly deposited by trough facies and carbonate plat⁃ form facies, the bottom⁃up low⁃level system tract is mainly composed of deep⁃water trough facies and shallow shelf facies sedimentation, the transgression system tract is mainly composed of deep⁃water trough facies and deep⁃water slope facies sedimentation, and the high⁃level system tract is mainly composed of deep⁃water gentle slope and tidal margin shore beach facies deposits. The average abundance of total organic carbon in the source rocks of Hongshuizhuang Formation was 4. 75% and (S1 + S2 ) was 6. 9 mg / g, which were generally good⁃very good source rocks, and the organic matter types were mainly Ⅰ⁃⁃Ⅱ1 type kerogen with great oil production potential, and the average Tmax was 438. 3 ℃ and the kerogen was brown, indicating that it was in the stage of mature oil production. On the whole, the trough facies black mudstone in the low⁃level system and transgression system tracts has great oil and gas potential, which is thefocus of the next exploration and research. 

To provide a scientific basis for disaster prevention，reduction management and land spatial planning in Shanwei，the authors conducted a geological disaster risk assessment and zoning using the information value method based on the ArcGIS platform，and proposed risk management and control recommendations based on the results. The results indicate that the types of geological disasters in Shanwei include collapses，landslides，and debris flows，primarily on a small scale. In terms of timing，geological disasters mainly occur from April to October，and spatially，they are predominantly distributed in Luhe County. The areas of high-risk，medium-risk，and low-risk zones account for 6.59%，29.81%，and 63.60%，respectively，with the high-risk zone covering an area of 289.81 km2，primarily located in the northern low mountain area，southwestern hilly areas，and central-eastern low mountain areas. The recommendations for geological disaster risk management and control include strengthening the identification of geological disaster risks，improving geological disaster risk assessment work，and fully implementing preventive measures during critical periods for geological disasters.