Following China's planning for ore prospecting in overburden areas, China's geochemical exploration researchers have conducted extensive research on the fundamental theories, methods, and technologies of geochemical exploration for overburden areas in the past decade. They achieved significant advances mainly in two aspects: (1) the research on the migration mechanism, occurrence state, and anomaly formation mechanism of elements in overburden areas; (2) advances in methods and technologies, including geoelectrochemistry, active state of elements, geogas, separation of micro-fine-sized soil particles, soil thermomagnetic composition, and integrated gas survey, as well as numerous experimental demonstrations. These advances represent continuous progress in the research on the fundamental theories, methods, and technologies of geochemical exploration for overburden areas, providing new geochemical methods and technologies for ore prospecting breakthroughs in overburden areas.

Xiong’an New Area is one of the areas with the best conditions for the development and utilization of geothermal resources in sedimentary basins of eastern China. Wumishan Formation of Jixian System is the main thermal reservoir, with buried depth of the top boundary varies greatly, which istypical carbonate type thermal reservoir. In order to find out the stratigraphic structure and concealed faults within 6 km of the starting area of Xiong’an New Area, focus on finding out the spatial distribution and structural characteristics of the main deep thermal reservoirs, and predict the favorable geothermal areas, the time-frequency electromagnetic method is applied to the geothermal resources exploration of Xiong’an New Area. Through high-standard data acquisition, refined data processing and resistivity-constrained inversion, the pseudo-seismic imaging technology and borehole data are used to calibrate the resistivity horizon, which effectively improves the reliability of interpretation results. In this work, 8concealed faults were identified, mainly NNE strike normal faults, which controlled the salient-depression pattern and stratigraphic distribution of the study area. The study area is divided into Rongcheng salient, middle sub-depression, Niutuozhen salient and Baxian depression from west to east. The thermal reservoirs of Wumishan Formation is mainly distributed in Niutuozhen salient, Rongcheng salient and middle sub-depression, with buried depth of top interface is about 600~2600m. Vsing the inversion results of the time-frequency electromagnetic method, the three-dimensional geological model of the study area is constructed, and the Niutuozhen salient area is considered to be the optimal geothermal favorable area from the aspects of heat source, channel, reservoir, caprock and fluid, especially near the footwall of F₄.

To evaluate the qualities of the marine magnetic data in the Earth magnetic anomaly grid EMAG2v3 and the marine gravity data in global gravimetric database V29, this study selected the magnetic and gravity data of the Aegir axial rift and its adjacent areas within a range of about 150 km from EMAG2v3 and V29, respectively to conduct comparative research. This study systematically collected the anomaly data of the study area from EMAG2v3 and V29 for comparison with the measured gravity and magnetic data of the study area. First, this study gridded and whitened the EMAG2v3 data, V29 data, and measured gravity and magnetic anomaly data to obtain the corresponding images. Then, this study analyzed the correlations between the EMAG2v3 data and the shipborne magnetic data and between the V29 data and the shipborne gravity data, obtaining the magnetic and gravity correlation diagrams and corresponding correlation coefficients. By comparing the correlation coefficients and differences between the two kinds of magnetic data and the two kinds of gravity data, this study conducted an integrated evaluation of magnetic the gravity data of the study area from EMAG2v3 and V29, respectively. As indicated by the results, EMAG2v3 incorporates many shipborne magnetic data, with the shipborne magnetic anomaly data showing higher quality than the data from the EMAG2v3 for areas with dense survey lines. The results also show that the shipborne gravity anomalies showed roughly the same variations as those from V29, indicating the same lateral resolution of the two types of anomaly data.

Since the periphery of the Xishan rare earth deposit in Weishan County, western Shandong is mostly covered by the Quaternary strata, single geophysical exploration methods are ineffective in searching for rare earth elements in this area. To establish a geological-geophysical prospecting model for deep rare earth prospecting in this area, a combination of exploration techniques and methods suitable for the deep exploration of rare earth deposits in this area were selected through multiple geophysical exploration technology experiments on the known geological profiles. The distribution range of the underground Mesozoic Xishan alkaline complex was roughly determined through gravity survey and high-precision magnetic survey. The ore body outcrop was delineated through ground-based gamma spectrometry, and the deep ore body characteristics were revealed through drilling. Finally, this study developed an integrated geophysical exploration method including gravity-magnetic joint delineation of rock masses, radioactive positioning for ore body outcrops, and deep drilling. By using this exploration model, one super-large rare earth deposit was discovered in this area, providing a reference for the exploration of rare earth deposits in the surrounding area.

The Luliang uplift zone in the Junggar Basin exhibits intricate fault structures,laterally heterogeneous reservoirs,and small-scale and thin gas-bearing sand bodies,presenting challenges in reservoir prediction.Hence,this study applied the wave impedance inversion technology based on wavelet edge analysis and well-seismic joint modeling to directly extract seismic attributes' characteristic parameters that reflect structural and lithological changes from seismic records.These seismic attribute characteristic parameters were used to build the initial model together with acoustic impedance logs and participated in disturbance modification of the wave impedance model.This inversion technology counteracted the lack of inter-well high-frequency components and the inter-well local lithologic changes during the inter-well interpolation modeling and avoided error information caused by the inaccurate initial model in the conventional wave impedance inversion,thus improving the resolution of seismic data in identifying small-scale and thin sand bodies.The results show that under the control of the provenance of the Kelameili Mountain in the east,a fan delta-semideep (deep) lacustrine sedimentary system formed in the Wutonggou Formation in the DX14 well area of the Luliang uplift zone,hosting many fan delta-front sand bodies.The comparison between the actual drilling results and the pre-drilling prediction results indicates that the absolute error and relative mean error of sandstone thickness prediction at the well site were less than 0.60 m and less than 2.84%,respectively,suggesting that the prediction accuracy meets the requirements of fine-scale reservoir prediction.The research results provide a guide for fine-scale reservoir description and well deployment.

Rapid progress has been made in the application of big data and artificial intelligence technology in the prediction of mineral resources. However, the application of machine learning technology based on convolutional neural networks remains in the exploration and experimental stages, with few practical examples and accomplishments achieved in the exploration and prediction of mineral resources in China. This study proposed applying convolutional neural networks to the exploration of gold deposits. Specifically, a neural network was trained for 2000 rounds using measured geological, mineral, geophysical, and geochemical data collected from a mineralization region covering an area of 3×10⁴ km² in a gold deposit in Shandong Province. Consequently, a 1D convolutional neural network model with accuracy of 0.95 and a loss rate of 0.11 was obtained. This model was employed to predict the distribution locations of gold deposits (exploration target areas) in other unknown areas in Shandong Province, yielding encouraging outcomes.

Audio magnetotellurics (AMT) is widely used for energy and mineral explorations because of its high exploration efficiency and high vertical resolution. Using a three-dimensional (3D) inversion algorithm based on data space, this study performed 3D inversion of the AMT data collected from geothermal exploration in the Santunhe area of Xinjiang. As indicated by the inversion results, the 3D inversion avoids the influence of inhomogeneous geobodies on the survey lines in the study area and yielded very rich and intuitive 3D geoelectric anomalies. In combination with the geological data and the 3D inversion results, this study analyzed the subsurface electrical properties of the study area and the formation water-bearing properties related to geothermal reservoirs, and finally inferred several favorable areas for geothermal reservoirs from the geothermal accumulation patterns of the study area.

Prior to the construction of an offshore channel, it is necessary to acquire data on the water depth and seabed sediments within the channel, aiming to determine appropriate dredging equipment and processes. Based on the mutual verification of data from existing tidal stations, offshore boreholes, and different exploration technologies, this study determined accurate water depth, seabed topography, and the thicknesses and distributions of sediments in both soft and hard oil layers utilizing the multibeam sounding and sub-bottom profiling techniques. Accordingly, this study summarized the technical measures, as well as the inversion characteristics of soft and hard soil layers of sediments, for offshore channel exploration. The obtained results are beneficial for the economical and efficient offshore channel exploration in sea areas with large waves using the multibeam sounding and sub-bottom profiling techniques. Furthermore, these results can be promoted to the exploration of subsea sediments containing toxic substances.

The Dongfang 1-1 structure is situated in the northern part of the central mud diapir tectonic belt of the Yinggehai Basin on the northern continental shelf of the South China Sea.The Dongfang 1-1 gas field is the first uncompartmentalized shallow gas field discovered in the Yinggehai Basin.Despite abundant oil and gas reserves in this region, the imaging of the diapir fuzzy zone has been a critical factor restricting oil and gas exploration in this region.The original streamer-based seismic data,through multiple rounds of multi-company reprocessing,still failed to effectively image the diapir fuzzy zone.Therefore,the second acquisition of three-dimensional ocean bottom node(OBN) seismic data was conducted in this region.According to the geological conditions and the characteristics of OBN data in this region,this study proposed several critical processing techniques,including OBN preprocessing,multi-component joint shear-wave noise suppression,wavelet-domain dual-sensor summation,and full-waveform-inversion(FWI) high-precision velocity modeling.These techniques effectively improved the imaging of shallow fault structures and middle and deep diapir fuzzy zones,thus providing reliable fundamental data for the subsequent target evaluation.

Rayleigh wave is widely used in engineering investigation and surveys.The inversion of its dispersion curves allows for effectively obtaining stratigraphic information.However,conventional global optimization algorithms in the dispersion curve inversion have a slow convergence rate and low convergence precision and are prone to prematurity.Therefore,this study introduced a novel global optimization algorithm—the sine cosine algorithm (SCA)—to solve the problems mentioned above.Based on the mathematical properties of sine and cosine functions,the SCA can adjust the exploration and development capabilities during the optimization using multiple random parameters and adaptive variables.As a result,it can ensure a high convergence rate and great stability while obtaining high-accuracy solutions.First,the feasibility of the SCA for the dispersion curve inversion was verified using four noise-free models.Then,the strong anti-interference ability of the SCA was proved by adding 15% of random noise to the models.Afterward,it was verified that SCA can yield high-precision,high-stability solutions in the dispersion curve inversion by comparison with the particle swarm optimization (PSO) approach.Finally,the practicability of the SCA was confirmed using seismic data from Arnarbælidi in Iceland and Wyoming in the USA.As indicated by the calculation results of theoretical models and the analysis of measured data,the SCA has a high processing speed,precision,stability,and practicability and thus allows for effective quantitative interpretation of the Rayleigh wave dispersion curves.

Based on the requirement of safe disposal of high-level radioactive waste, this study aims at the pre-selection area of the preferred pre-selection area of China's high-level radioactive waste disposal bank (Beishan pre-selection area). The data and materials of geology, hydrogeology, future natural change, geochemistry, construction and engineering, environmental protection and social economy were obtained by using the methods of geology, geophysics, hydrogeology and geochemistry. The constructability of preselected rock mass is demonstrated from the perspectives of engineering construction and engineering safety. The acceptability of the preselected rock mass in transport condition, land use, social economy and humanity was confirmed. On this basis, a relatively perfect site investigation and suitability comprehensive analysis method for the disposal warehouse is established, and a candidate site for the granite disposal warehouse is selected from the computational sub-section through the comprehensive analysis of site suitability and the comprehensive comparison of site identification and safety in the lot. The research results will directly serve the site screening and site characteristics evaluation of China's high-level radioactive waste geological disposal repository, and have important practical significance to ensure the safe management of nuclear waste and the sustainable development of nuclear energy in China.

Normally pressured shale gas reservoirs in southern China,exhibiting significant potential resources,are primarily distributed in Silurian residual synclines at the periphery of the Sichuan Basin.Given intricate geological conditions in the study area,seismic data with high signal-to-noise ratios(SNRs) are required for fine-scale characterization of underground structural features and accurate description of the distribution patterns of high-quality shales.The purpose is to improve the probability of penetration of high-quality shales in horizontal wells and the drilling efficiency.Since 2011,the research and application of seismic data acquisition have been continually conducted in the Pengshui area.This study systematically summarized the methods,effects,and deficiencies of relevant projects implemented,and analyzed regional noise characteristics,the influence of channel spacing on static correction,and the degradation of the 3D seismic observation system.The results are shown as follows:(1)The 2D seismic data acquisition profiles displayed relatively clear reflection wave groups of shales in the Wufeng-Longmaxi formations,supporting the target selection and evaluation of normally pressured shale gas reservoirs;(2)The design principles of a 3D observation system,characterized by a wide azimuth,a low shot density,a high lateral fold number,and rich medium-near offset information, were proposed in this study;(3)The 3D seismic data processing profiles manifested high SNRs and clear wave group characteristics.The drilling results reveal accurate 3D structure imaging and a formation depth prediction error below 1%,strongly supporting shale gas exploration and production.The technical system in this study can be applied to similar exploration areas of normally pressured shale gas reservoirs.

Since the current instrumental measurement technology cannot directly measure the third-order gradient tensor of gravitational potential, this study proposed a wavenumber-domain transform calculation method for the third-order gradient tensor of gravitational potential based on the gravity anomaly and gradient tensor data. To verify the correctness of this method, this study computed the third-order gradient tensor anomalies of gravitational potential using a 3D model and compared the wavenumber-domain transform calculation results with the forward modeling results, suggesting that the wavenumber-domain transform calculation method is feasible. Moreover, the wavenumber-domain transform calculation results based on gravitational gradient tensor data were more accurate than those based on gravity anomaly data, yielding a root mean square error not exceeding 1 pMKS. In addition, based on the measured data of the Vinton salt dome area, the third-order gradient tensor data of gravitational potential of this area were obtained using the wavenumber-domain transform calculation method. The obtained data were used for DEXP-based data interpretation, attaining consistent depth and boundary results with the previous research results.

Traditional inversion techniques rely on initial models and exhibit prolonged inversion times. This study proposed a magnetotelluric inversion method based on an improved residual network. Specifically, geoelectric models of varying shapes and resistivity values were established, and apparent resistivity data were obtained using the TM mode, forming a dataset. Then, a novel inversion network-iResNet (an improved residual network)-was established by improving classic residual network ResNet, and the new network was trained using the afore-mentioned data set. Finally, the apparent resistivity data were input to trained network, directly producing inversion results. The experimental results demonstrate that the method proposed in this study can accurately determine the positions, shapes, and resistivity values of the geoelectric models through swift inversion, suggesting high generalization and anti-noise capabilities. Therefore, this method can effectively deermine measured magnetotelluric data.

High-density resistivity method is widely used in engineering exploration because of its efficient and intuitive features. However, due to the high nonlinearity of the inversion problem, the traditional inversion method has some inaccuracy in describing the boundary of anomalous body. In order to achieve high precision two-dimensional nonlinear inversion imaging with high-density electrical method, to overcome the problem that a large number of saddle points in the parameter space of loss function of BP algorithm affect the calculation accuracy and that it is difficult to assign optimal weight threshold to BP network due to the precocious convergence of general genetic algorithm. In this paper,an Optimum Maintaining Adaptive Genetic Algorithm(OMAGA)is proposed to optimize the BP neural network for high density electrical two-dimensional inversion imaging. Good results have been obtained for the inversion calculation of simulation model data and measured data through this method, it shows that this method has strong generalization ability and high inversion accuracy. This study is helpful for the accurate inversion of high density resistivity method in the future,it is helpful to improve the accuracy of underground target identification.

Ambient noise surface wave imaging has been widely applied in the engineering exploration of large-scale regional structures and shallow parts. However, there are limited studies on the exploration of mineral resources at depths ranging from several hundreds of meters to one kilometer. The noise source utilized for exploration at this depth range is human environmental noise with frequencies from a few Hz to over ten Hz, varying greatly in time and space. To examine the applicability of ambient noise imaging in the exploration of coal mines, this study systematically analyzed noise source distribution and the adaptability of various array dispersion imaging schemes using experimental data from the Libi Coal Mine. As revealed by the results, the noise in the coal mine is dominated by that with frequencies below 2Hz at night and by that above 2Hz during the day. The noise frequency band (2~10 Hz) utilized for the No. 3 coal seam at a depth of 700m is primarily distributed in the southeast. In the case of simple frequencies and azimuths of the noise sources, a linear array in the noise source direction can obtain dispersion data with higher quality than a triangular array. Finally, by extracting dispersion data from a linear array in the NW direction, the 1D velocity structure below the linear array was obtained. By comparison with the lithology column of borehole ZK101 near the linear array, the 1D velocity structure, obtained through ambient noise imaging, corresponded well with the underground lithology. This result indicates that when fully considering noise distribution, the ambient noise imaging based on a linear array can yield reliable velocity structures for layers at depths less than 1 km in a coal mine.

Convolutional neural networks(CNNs) have achieved good results in seismic wave impedance inversion,but the inversion accuracy and anti-noise performance need to be improved.Hence,this study proposed a seismic wave impedance inversion method based on the fully convolutional residual shrinkage network with channel-wise thresholds(FCRSN-CW).In this method,the attention mechanism and the soft thresholding were first added to the structure of the residual network to form a inversion network.Then,a synthetic seismic dataset was obtained through forward calculation using wave impedance data.Subsequently,the dataset was applied to train the FCRSN-CW.Finally,the seismic data were put into the trained FCRSN-CW to obtain the inversion results directly.The inversion results of the theoretical model show that the FCRSN-CW can accurately invert the wave impedance and possesses satisfactory learning capacity and anti-noise performance.The inversion results of field data demonstrates that the method based on FCRSN-CW can effectively achieve seismic wave impedance inversion.

Uranium ores, as a significant clean energy source, have been highly anticipated in the field of geological exploration. However, fractured sandstone-hosted uranium deposits (pore-fissure type uranium deposits) face challenges in exploration because of their complex structures. Therefore, to quantify such uranium deposits, it is necessary to investigate the response relationships between the occurrence state and content of uranium and the parameters of geological structures (pores and fissures). This study simulated the neutron migration in the pore-fissure type sandstone-hosted uranium deposits using the prompt neutron log technology and the directive probability simulation algorithm. Through an ideal model, this study focused on the effects of fracture structures on neutron logs. The results are as follows: (1) The effects of fissure porosity on epithermal neutron migration intensified significantly with an increase in porosity, accompanied by substantially enhanced log response sensitivity; (2) The epithermal neutron accumulation peaks exhibit a multi-point distribution in a nearly vertical fissure environment; (3) The fracture environment with high dip angles manifested the most significant attenuation effect on the neutron energy and time spectrum peaks, and the neutron time spectrum peaks tended to move to the low-dip-angle interval with an increase in porosity; (4) In the fracture environment with variable dip angles, there was a linear relationship between the porosity and the epithermal neutron count ratio, which can assist in correcting the uranium content range in fracture environments at specific angles. The above results can provide a theoretical reference for the exploration of fractured sandstone-hosted uranium deposits and other uranium deposits in a complex environment and improve the quantitative accuracy of uranium deposits.

Structural interpretation based on seismic data is a critical task in geophysical research,and the results are mainly manifested as contour maps.However,most imported seismic interpretation systems used in the petroleum industry of China fail to provide contour maps that meet national,industrial,or enterprise standards, making post-processing necessary for the resultant contour maps using independent mapping software.The post-processing process involves many human-computer interactions,with the time for mapping accounting for about 20% of that for seismic interpretation.Therefore,based on the existing software and the types of data to be processed (contours,faults,and three-dimensional grids),this study proposed an automatic processing and mapping algorithm for multi-type seismic data.Furthermore,it designed the automatic mapping software for the integrated processing of various data of maps to be interpreted.The software can achieve one-click export of data of a GeoFrame working area and the automatic processing of multi-type data such as contours,faults,and grids,greatly simplifying the seismic data processing flow in the mapping process.Presently,the software has been widely used in practical production projects,improving the mapping efficiency by about 90% and effectively reducing the mapping error rate.

With an increase in the difficulty with the exploration of oil, gas, and mineral resources, conventional log and seismic methods fail to accurately evaluate the geological structures and transverse reservoir distribution far from boreholes. Therefore, this study proposed a transient electromagnetic (TEM) method for long-distance exploration of boreholes. Specifically, this study investigated the influence of key parameters of TEM devices for boreholes on the exploration distance. Based on the finite element analysis, this study calculated the responses of low- and high-resistivity geobodies under different receiver-transmitter distances, coil parameters, and exploration distances. The results showed that receiver-transmitter distances had little effect on the distance of electromagnetic exploration in the temporal domain. However, the results indicated that coil parameters had significant effects on the near-well detection distances. Under the transmitter coil parameters of 200 turns and 2A current, the TEM method for boreholes was more sensitive to low-resistivity geobodies, with near-well exploration distances reaching 40~50 m and 30 m for low- and high-resistivity geobodies, respectively. Therefore, it is feasible to conduct short-offset near-well long-distance exploration using TEM detectors with short transmitter coils for boreholes.

Ground roll is a type of common regular noise and features low frequency,low velocity,strong energy,and dispersion.It overlaps with effective waves in terms of frequency bands,propagation direction,and velocity,making the transform-domain filtering methods fail to yield desired denoising results.At present,prediction plus matched subtraction is the mainstream ground roll suppression technique in the industry.However,direct predictive modeling of the ground roll is often difficult and of limited accuracy due to the complex wavefield propagation process near the surface.This study proposed a new ground roll suppression technique based on invertible superposition transformation.The main approach is as follows:first,the reflected waves can be modeled using a superposition operator in the CMP domain to construct an inverse problem for reflected wave estimation.Then the inverse problem is solved using an optimization method.The whole process is equivalent to the projection of seismic data to the reflection space.Since ground roll and reflection waves reside in different spaces,clean reflected wave data can be obtained through projection.To reduce the influence of ground roll on inversion results,this study used a data preconditioner to reduce the leakage of ground roll,achieving effective noise suppression effects.

The joint processing and integrated interpretation of multi-source geophysical exploration data are indispensable to the exploration evaluation of deep geothermal resources. Joint inversion and post-inversion geological differentiation are two major hot research topics in deep resource exploration. To integrate the multi-source geophysical field information and reduce the inversion multiplicity of single geophysical fields, this study built a structural model using the stratigraphic structure information from seismic interpretation, with the prior information of petrophysical properties as a guide. This study constrained the stratigraphic geophysical parameters using the Gaussian mixture model and conducted regularized joint inversion of gravity, magnetic, and magnetotelluric data, thus achieving the coupling of multiple physical structures. Finally, this study developed the software for the joint inversion of gravity, magnetic, magnetotelluric, and seismic data. Based on the joint inversion results and electrical resistivity, this study predicted the temperature field at typical hot dry rock sites using the Arrhenius law. The forward modeling results of the theoretical model for cubic anomalies were used for the joint inversion. Compared with individual inversion, the joint inversion performs well in the spatial characterization of anomalies and the recovery of physical property values. Furthermore, the joint inversion can fully integrate multiple data on geology, petrophysical properties, and geophysics, thus well conforming to the actual conditions.

The resolution of seismic data directly influences the characterization accuracy of oil reservoirs. To improve the resolution for effective sand body prediction, this study established a frequency enhancement technology process based on time-varying frequency-division deconvolution for thin oil-bearing sand bodies occurring in complex fault blocks. First, seismic signals were separated into different time windows, in which seismic wavelets were computed to obtain their amplitude spectra. Then, the corresponding seismic wavelets were deconvoluted within each time window to obtain the reflection coefficients. Finally, high-resolution broadband seismic signals were attained by integrating the reflection coefficients of the entire seismic data and convolving high-and low-frequency wavelets. This technology process was employed to process the actual 3D seismic data from the Wennan area of the Zhongyuan Oilfield. As indicated by the results, this technology process had a significantly elevated capacity to depict a single sand body by expanding the high-frequency effective information in acquired 3D post-stack seismic data, thus yielding high-quality data for the identification of thin sand bodies. Moreover, the prediction results were highly consistent with the actual drilling results. Therefore, the time-varying frequency-division deconvolution has great potential for application in complex fault blocks.

Low frequency model is an important part of seismic inversion,and its accuracy directly affects the precision of inversion.With the continuous deepening of exploration degree,the exploration of mid-deep continental strata has become a key area of offshore exploration.The lateral variation of sedimentation in continental strata is fast,and there are few wells drilled during the exploration phase.It is difficult to obtain accurate low frequency models through conventional interpolation methods,which restricts the accuracy of seismic inversion.To address these issues,we studied a low frequency model construction method based on co-kriging technology. Using spatially continuous seismic velocity data as auxiliary variables and high-resolution logging data as main variables,we integrated the auxiliary variable information into the estimation results through co-kriging interpolation method,thus compensating for the shortcomings of insufficient spatial measurement of the main variable data and obtaining a high-precision inversion low frequency model.This solves the problem of constructing low frequency models in areas with few wells.Practical application of the data shows that this method improves the accuracy of the inversion low frequency model compared to conventional methods,enhances the reliability of reservoir prediction,and has wide application prospects.

Dry and wet atmospheric deposition is an essential input pathway for surface soil elements. To explore the geochemical characteristics and sources of elements from atmospheric deposition in the middle-high mountain and hilly region of Central Yunnan, this study investigated 35 dry and wet atmospheric deposition samples from three counties in Central Yunnan. The results show that nutrient elements exhibited high annual depositional fluxes, while heavy metal elements manifested low annual depositional fluxes, with their ranking as follows: TOC>Ca>K>I>F>Zn>B>Pb>Cr>Cu>As>Mo>Cd>Se>Ge>Hg. As revealed by the enrichment factors, principal components, and spatial distribution characteristics, Ca, Mo, B, As, and F originated primarily from soil dust; Cu, Cd, Pb, Cr, and Ge were mostly from anthropogenic sources, such as mining activities and coal dust; TOC, K, Se, and I came from both coal dust and soil dust, and Se was also affected by mining activities; and Hg stemmed from coal dust. Coal and copper-dominated polymetallic mineral resources spread extensively across the study area and are subjected to certain mining activities, which are intimately connected with the contents of heavy metals in the atmosphere. Therefore, targeted atmospheric monitoring should be conducted to ensure atmospheric quality and no pollution to soil.

Yongqing County, as a pivotal pollution-free vegetable production base in the Beijing-Tianjin-Hebei region, has made significant contributions to ensuring the food safety of this region. However, there has been no systematic and comprehensive evaluation of Yongqing County's soil fertility, hindering the sustainable development of its green food industry. This study collected 338 soil samples from the arable layer (depth: 0~20 cm) throughout the county, including 155 from dry land, 84 from vegetable plots, and 99 from garden plots. Four soil nutrient elements including organic matter, total nitrogen, available phosphorus and potassium were determined using these samples. The results show that: The average contents of organic matter, total nitrogen, available phosphorus, and rapidly available potassium in the soil samples from Yongqing County's arable layer were 5.29×10^-3, 0.78×10^-3, 41.8×10^-6, and 197×10^-6, respectively. The soil fertility generally exhibited deficient organic matter and total nitrogen and abundant available phosphorus and potassium. In addition, the soil fertility of Yongqing County was graded and evaluated according to China's agricultural standard Green food-Environmental quality for production area (NY/T 391—2021). For land-use types like dry land, vegetable and garden plots, their organic matter and total nitrogen contents were mostly at level Ⅲ, and available phosphorus and potassium contents were primarily at level Ⅰ. The soil nutrient contents differed significantly in spatial distributions. Specifically, Longhuzhuang, Liujie, and Yangmazhuang townships in the southwest generally had higher soil nutrient contents than Caojiawu Township, Hancun and Lilancheng towns in the northeast. To efficiently develop the green food industry, Yongqing County needs to apply fertilizers scientifically and properly according to land-use types and actual planting situations and considering the soil texture and natural geographical factors. The specific measures are as follows: increasing the organic matter and total nitrogen contents in the soil by applying more organic and nitrogen fertilizers; applying more phosphate and potassium fertilizers to soil lacking available phosphorus and potassium, otherwise, the application of such fertilizers should be controlled.

Based on the 1∶50 000~1∶2 000 land quality geochemical survey data and the requirements of the Delimitation and the Logo for Natural Selenium-enriched Land (DZ/T 0380—2021), this study evaluated the selenium (Se) content, environmental quality, fertility quality, and irrigation water quality of soil in Sanhe Town, Ping'an District, Haidong City, Qinghai Province. The evaluation results show that: (1) The soil in Sanhe Town was alkaline; (2) The soil Se content ranged from 0.093×10^-6 to 1.938×10^-6, averaging 0.425×10^-6; (3) The Cd, Hg, Pb, and Cr contents in the soil were all below the risk screening values of soil for agricultural land, while the As content in the soil in the southern portion of the study area was higher than its risk screening value; (4) The quality of irrigation water met the standard specified in the Green Food-Environmental Quality for Production Area (NY/T 391—2013), and the soil fertility was characterized by rich available phosphorus and potassium, and moderate nitrogen and organic matter. Based on the above evaluation results, this study delimited contiguous natural green Se-rich land of 40.46 km², including 12% directly usable arable land (4.76 km²), and 88% potentially usable grassland (7.84 km²) and forest land (27.86 km²). They are distributed primarily in six villages, including Zhangqizhai, Luotuobao, Xicun, Dongcun, Qixinzhuang, and Sanhe villages. Considering the Se-rich industry planning and local conditions, this study proposed developing Se-rich planting in arable land and Se-rich animal husbandry by utilizing natural Se-rich forage in forest land and grassland.

The integrated geogas survey is a prospecting technology that integrates geogas survey and X-ray fluorescence measurement for exploring concealed ores based on the prospecting needs of pegmatite-type rare metal deposits. This technology utilizes handheld X-ray fluorescence instruments for rapid measurement to capture secondary or primary halos on the surface, enabling the evaluation of the occurrence positions, strikes, and extension lengths of ore-hosting pegmatite veins on the surface. Moreover, it employs a dynamic geogas survey to capture deep mineralization information for evaluating the deep ore-bearing potential and extension depths of the pegmatite veins. This study demonstrated the main technical methods of the integrated prospecting technology and the application cases of ore prospecting supported by relevant projects in different geochemical landscape environments, in order to provide reference for the extension and application of this method and subsequent prospecting word in similar landscape areas.

The research on exploring pegmatite-type lithium-beryllium deposits through soil X-ray fluorescence measurements was conducted in the Chakabeishan exploration area of Ulan County, Qinghai Province. The results demonstrate that soil secondary halos formed by granite pegmatite-type lithium-beryllium deposits can be accurately captured by measuring two groups of indicator elements, i.e., Ca, Ni, Mn, Fe, and Nb, Ta, Rb, K. The X-ray fluorescence anomalies of the first group of elements indicate the position of the ore-hosting horizon (i.e., granitic pegmatites). Those of the second group of elements are used to determine the location, strike, and planar extension range of the pegmatite veins with mineralization manifestation. As inferred from the captured X-ray fluorescence anomalies, the main ore veins in the exploration area exhibit significant extensions along the northwest and southeast directions. This conclusion provides a reference for further prospecting work.

To provide deep prospecting support for the exploration of lithium-beryllium deposits in the Chakabeishan area, two geogas prospecting profiles each with a length of 800 m were laid out in the exploration area, obtaining the content information of over 30 elements such as Li, Be, Cs, Nb, Rb, Ti, and rare earth elements in the geogas samples from 162 measuring points. Combined with the existing exploration results, the characteristics of local geogas anomalies were investigated in this study. The results are as follows: (1) Significant geogas anomalies of various elements can be detected above the concealed sections of pegmatite veins and beryllium ore bodies; (2) The combined anomalies of elements Li, Rb, Th, Cs, Pb, Nb, Ti, La, and Ce in geogas can indicate pegmatite veins, while the combined anomalies of elements Be, Rb, Nb, Cs, Pb, Ti, and Cu can directly indicate concealed beryllium ore bodies; (3) Be anomalies can indicate beryllium ore bodies within a burial depth of 480 m. This study demonstrates that geogas prospecting can be used to predict the ore-bearing properties of concealed pegmatite veins in the Quaternary coverage area.

In this study, six survey lines were deployed in the Huangbaishan survey area in the periphery of the Renli mining area in southern Hunan Province. An integrated geogas prospecting was applied to explore granite pegmatite-type rare metal deposits in the study area. Based on the characteristics of soil X-ray fluorescence and geogas anomalies above the known pegmatite veins in the mining area, this study captured five soil X-ray fluorescence anomaly zones aligning with the formation trend, with the (Nb+Ta+Rb) cumulative value obtained from X-ray fluorescence measurements as the primary prospecting indicator. The Nos. 1~4 anomaly zones exhibit consistent spatial positions with the known pegmatite veins. Accordingly, this study inferred the positions, trends, and lengths of possible pegmatite veins, and a possibility of extension for the known veins based on the anomaly length. The No. 5 anomaly zone discovered on the south side of the survey area, with a length exceeding 1 000 m, serves as a new prospecting target. Geogas prospecting was conducted along the No. 11 survey line in the middle of the No. 4 anomaly zone with a length of over 1 500 m, capturing the geogas anomalies of elements Li, Be, and Nb that reflect the deep mineralization information of pegmatite veins. This confirms that pegmatite veins in the survey area have significant extensions towards the deep part.

In recent years, several pegmatite veins have been discovered in the Hongling area of Hami, Xinjiang, suggesting a promising prospect for pegmatite-type rare metal deposits. In this study, two long profiles crossing the main pegmatite veins were deployed in the area, and the integrated geogas prospecting technology was applied to evaluate the ore-bearing properties of the main pegmatite veins. Rapid soil X-ray fluorescence measurements performed by a handheld X-ray fluorescence instrument were used to evaluate the ore-bearing properties of the top or exposed parts of the pegmatite veins. The dynamic geogas prospecting method was employed to obtain the deep mineralization information of the pegmatite veins for evaluating their deep ore-bearing properties. The results show that many pegmatite veins in the Hongling area exhibit mineralization manifestations on their surfaces and in deep parts. Therefore, they are worthy of further prospecting work.