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

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

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

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

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

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

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

To investigate the Early Cretaceous magmatic activity and tectonic evolution in the Xiaoqinggou mining area of Jilin Province, the authors conducted petrological, geochemical, and isotopic analyses of diorite rocks. The findings show that the zircons exhibit distinct magmatic growth zoning, confirming their magmatic origin. LA–ICP–MS zircon U–Pb dating yielded an age of 128.7±2.2 Ma, corresponding to Early Cretaceous. Geochemical data reveal that the diorite rocks are high and potassium but low in sodium, classifying them within the peraluminous, high-potassium calc-alkaline series. They are enriched in large ion lithophile elements (e.g., K, Ba and Rb) and depleted in high field strength elements (e.g., Nb, Ta and Ti). The δEu values range from 1.07 to 1.14, indicating weakly positive Eu anomalies. Regional comparisons and integrated studies suggest that the Xiaoqinggou diorite rocks formed in a volcanic island arc setting, associated with the westward subduction of the Paleo-Pacific plate beneath the Eurasian continent in an extensional tectonic environment. This study provides a theoretical basis for further exploration of the Xiaoqinggou deposit.

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

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

There is an issue of groundwater overexploitation in Ningjiang District, Songyuan City, Jilin Province, which has led to land subsidence. To investigate the influence of hydrological elements on surface deformation in Ningjiang District, surface deformation data were obtained by the small baseline subset interferometry synthetic aperture radar (SBAS-InSAR) technique. Initially, Sentinel-1B data were utilized to observe surface deformation in Ningjiang District from 2017 to 2021 with SBAS-InSAR. Subsequently, the geographical detector was employed to quantitatively assess the relationship between land subsidence and its influencing factors. Furthermore, multivariate singular spectrum analysis (M-SSA) was employed to identify periodic fluctuations in surface deformation and groundwater level, revealing the temporal lag between f luctuations in surface deformation and groundwater level. The findings demonstrate that the distance to water bodies accounts for the largest share of subsidence variation, with subsidence shaped by the combined impact of many factors. The results of interaction detection indicate that the interplay between the distance to water bodies and precipitation exhibits the most significant joint explanatory capacity for surface deformation. The observed seasonal cyclical fluctuations in groundwater level and surface deformation indicate a substantial influence of groundwater on surface deformation in the Ningjiang District.

 Evaluation of backfilling effectiveness plays a crucial role in the geological environment management and restoration of abandoned open-pit quarries, providing a scientific basis for subsequent greening efforts. Backfill soil, predominantly composed of silty clay, demonstrates high water retention capacity and elevated moisture content, leading to a pronounced resistivity contrast with the bedrock exposed by quarrying activities. To investigate the distribution of backfill soil subsurface and assess backfilling effectiveness in the study area, this study conducted a comprehensive geophysical investigation utilizing the high-density electrical resistivity tomography (ERT). A total of 19 ERT survey lines were deployed across three distinct areas in Liuyao Village, Huaibei City, Anhui Province, China. The inversion results, derived from both two-dimensional (2D) and three-dimensional (3D), reveal distinct electrical properties of the subsurface materials: the backfill soil layer shows low resistivity features, the fill stone layer exhibits medium to high resistivity, and the bedrock shows the highest resistivity. The 2D inversion results, from the data measured using the Wenner array effectively capture the spatial distribution and structural features of the backfill soil layer. The findings indicate a gradual east-west thinning of the clay layer within the quarry. Furthermore, the northern pit area exhibits a uniform distribution of backfill soil layer, indicative of effective backfilling operations. In contrast, the southern pit area lacks a well-defined clay layer, suggesting suboptimal backfilling effectiveness.

The large-scale acquisition and widespread application of remote sensing image data have led to increasingly severe challenges in information security and privacy protection during transmission and storage. Urban remote sensing image, characterized by complex content and well-defined structures, are particularly vulnerable to malicious attacks and information leakage. To address this issue, the author proposes an encryption method based on the enhanced single-neuron dynamical system (ESNDS). ESNDS generates high quality pseudo-random sequences with complex dynamics and intense sensitivity to initial conditions, which drive a structure of multi-stage cipher comprising permutation, ring-wise diffusion, and mask perturbation. Using representative GF-2 Panchromatic and Multispectral Scanner (PMS) urban scenes, the author conducts systematic evaluations in terms of inter-pixel correlation, information entropy, histogram uniformity, and number of pixel change rate (NPCR)/unified average changing intensity (UACI). The results demonstrate that the proposed scheme effectively resists statistical analysis, differential attacks, and known-plaintext attacks while maintaining competitive computational efficiency for high-resolution urban image. In addition, the cipher is lightweight and hardware-friendly, integrates readily with on-board and ground processing, and thus offers tangible engineering utility for real-time, large-volume remote-sensing data protection.

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

 The detection of unexploded ordnance (UXO) is critical for battlefield clearance and civilian safety. This study presents the development of a software for automated simulation based on the high frequency structure simulator (HFSS) and the MATLAB application programming interface (API), which together form the HFSS-MATLAB-API. This interface enables control over HFSS and conducts frequency-domain electromagnetic simulations for various types of UXO, including anti-tank mines, grenades, mortars, and aerial bombs. The software automates modelling, solving, data extraction, and analysis through MATLAB, enhancing the efficiency of simulation and enabling flexible settings for target models, coil parameters, and subsurface media. The research utilizes numerical simulation methods to analyze the response characteristics of different types of UXO in electromagnetic induction and explores the impact of the rotation angle of the target model on the attenuation characteristics of the measurement line. The results indicate that the electromagnetic response of UXO varies significantly based on type, burial depth, and spatial orientation. The findings provide a theoretical foundation for the electromagnetic detection, target identification, and classification of UXO.