Grounded-source transient electromagnetic method (TEM) has many advantages such as deep exploration, flexible arrangement in rough terrain and high working efficiency. Recently it has got much attention and a series of new methods are available, ranging from surface to airborne and borehole method. In this paper, the authors review the research history of long-offset TEM (LOTEM), short-offset TEM (SOTEM), multi-channel TEM(MTEM), grounded-source semi-airborne TEM and grounded-source surface to borehole TEM, and summarize their research status in forward modeling, system design, inversion, imaging and field working. The results show that, as a well-developed grounded-source TEM, LOTEM has accumulated many research achievements. Although some progress has been made, the researches on other grounded-source TEMs are still in a primary stage and still need further improvement. Valuable research results in LOTEM, for example, noise suppression technology, high dimensional inversion and point interpretation, can be introduced to these newly developed electromagnetic methods, which can help provide solutions for high working efficiency and high resolution deep exploration.

This paper has summed up the progress of the ERI method over the past decade of years as well as its future development trend in the following aspects: ① A comparison of the performances of the main ERI instruments used at present shows that the ERI instruments tend to develop in the multi-channel, multi-parameter, multi-functional, high-power direction; ② ERI measurement environment has changed from surface measurement to water surface, underwater and cross-hole measurements, with the last three kinds of measurements analyzed in this paper; ③ On the basis of analyzing ERI data processing method and inverse development status, this paper describes three-dimensional and four-dimensional inversion theory of ERI with practical examples; ④ ERT applications are summed up, and several new applications are introduced. It is concluded that, with the improvement of the probing depth and observation precision as well as the diversification of the observation models, the application field of ERI will become broader and broader, and this technique will surely have wide development prospect.

China's complicated geological background and metallogenic environment have decided that the regional geochemical exploration can play an important role in the field of China's mineral resources prospecting. This is the strategic selection under special metallogenic conditions. The first round of regional geochemical exploration of China was carried out during mid-1950s. Since then, we carried out the second and third round of regional geochemical exploration. Until now, China's regional geochemical exploration has gone through a history of 70 years, and showed unique functions in fields of the exploration and development of nonferrous metals, precious metals as well as the rare minerals, rare earth and scattered minerals. According to incomplete statistics, during 36 years (1979~2015) of the second and third round of regional geochemical exploration, totally 182 different kinds of large to super-large scale deposits were discovered in China mainly by means of regional geochemical exploration. Of which, 61 deposits have nonferrous metals, 93 deposits have precious metals, 24 deposits have critical and scarce minerals, and 4 deposits have other kinds of minerals. On average, 5.06 large to super-large deposits were discovered each year, and one large to super-large deposit was discovered within every 37,000 square kilometers-Calculated on the basis that the second and third round of regional geochemical exploration covered 6.68 million square kilometers' area of China. Regional geochemical exploration has achieved outstanding results in the field of mineral prospecting, and made great contributions in terms of ensuring and promoting China's economic development. As our country's basic, public good and strategic geological work, regional geochemical exploration comes into the 21^st century marked by big data and earth system science. Based on high precision and good quality big data, guided by metallogenic geochemical theories, and supported by modern science and technology, the regional geochemical exploration will start a new period of development. In the future, we'll continue to carry out the high technical standard and high quality regional geochemical exploration, achieve our goal of complete covering the whole area of mainland China with regional geochemical exploration, and provide more strategic prospective areas for our country's mineral resources exploration. On the basis of high-precision big data, metallogenic theories and modern science and technology, we'll establish AI and IT application system, so as to push forward the exploration and utilization of deep minerals, buried deposits as well as the critical and scarce minerals which are difficult to identify, and achieve greater breakthroughs in the geological exploration of mineral resources. By using big data technics, China's regional geochemical exploration team will continuously solve the mineral resources exploration and evaluation problems, and in this process, our geochemical exploration system will be gradually integrated into our country's science and technology advancement.

Due to historical reasons, the present coordinate systems of the geological, geophysical and geochemical exploration results are basically WGS84, BJ54 or XA80 systems; nevertheless, according to the NASG requirements on the overall use of CGCS2000 coordinates, in the future the coordinates for all kinds of results should be CGCS2000 coordinates, which causes inconvenient situation in using the results and in comprehensive research work. As a professional geographic information system software, ArcGIS has a wide range of applications in various walks. In this paper, the authors briefly introduced the ArcGIS built-in coordinate system, studied and deduced the calculation formula of the MOLODENSKY coordinate conversion method in ArcGIS, put forward the method to get the conversion and precision evaluation of transformation parameters between different ellipsoids, and cited practical examples for verification. On such a basis, the specific ideas and points for attention were analyzed for each coordinate system in the conversion of ArcGIS software to CGCS2000.

The finite element method has the characteristics of strong adaptability in simulating the electromagnetic response of rugged topography and complex geological bodies. In recent years, it has been widely used in the three-dimensional (3D) forward modeling of magnetotelluric (MT) sounding. However, the finite element method also has some shortcomings in terms of computational efficiency. The large amount of calculation and long running time of the method are the main factors that lead to the lag of the practical process of the 3D MT inversion technology based on the finite element method compared with the 3D MT inversion technology based on the finite difference method. In order to improve the 3D forward speed of MT, the authors adopt the forward modeling scheme which uses the direct solver PARDISO and does not need divergence correction to solve the large-scale linear equations corresponding to the vector finite element method, and obtain the MT response of the geoelectric model under such different terrain conditions as flat and rugged topography. Under the conditions of medium-scale calculation, through the comparison between the direct solution method without divergence correction and the iterative solution method with divergence correction, the authors have detected that the direct solution method without divergence correction has advantages in calculation accuracy and calculation time, especially in the calculation. In terms of time, the ratio of the calculation speed of the direct solution and the iterative solution is raised by more than ten times.

According to the regional geophysical data, the Altun-Qilian arc giant gravity gradient zone is located at the northeastern edge of the Qinghai-Tibet block and forms the boundaries between Qinghai-Tibet block, Tarim basin and North China block. With the NEE-trending gravity gradient zone, this zone reflects the Altun fault characterized by both sinistral strike-slip and thrust. West Qilian is characterized by alternate NWW-trending arc gravity high and gravity low, which reflects the framework of squeeze nappe, thrust superposition and basin-range coupling within the Qilian orogenic belt. Between Dunhuang and Jinta, due to the tail effect of northeast Altun fault, a series of NNE-trending pull-apart fault basins associated with NEE-trending strike-slip fault and filling of mainland alkaline basalt in the pull-apart space were produced, which caused corresponding magnetic anomalies characterized by gravity low. Due to energy reduction and conversion, the Altun fault terminated in Huahai fault of Jinta basin, thus not extending eastward.

Porphyry copper deposit is the most important copper deposit type in China. With the deepening of mineral exploitation, exploration geochemistry in mineral exploration has become increasingly important. Based on related literature, this paper sums up the exploration geochemical research results of porphyry copper deposits, which include such aspects as geochemical characteristics, exploration methods, anomaly evaluation and prospecting indicators. Exemplified by the Fujiawu copper deposit, this paper reports the latest advances in the study of porphyry copper deposits.

Studying the occurrence of natural gas hydrates (NGHs) is of profound significance for NGH exploration. The evaluation of the NGH saturation mainly relies on the Archie equation using the electrical parameters of rocks. The key to accurately calculating the NGH saturation is to select corresponding values of rock electrical parameters for different geological environments, especially the porosity index (m) and the saturation index (n). However, it is still a challenge to select the optimal m and n values for NGH evaluation in resistivity logging. To ascertain the relevant resistivity regularity of NGHs and the determination method of rock electrical parameter values in the Archie equation, this study systematically reviewed relevant references and summarized the resistivity influencing factors of NGHs. Moreover, this study analyzed the influencing factors for the accurate evaluation of the NGH saturation based on the Archie equation. Accordingly, this study generalized the resistivity characteristics of NGH-bearing sediments and proposed the application research direction of the Archie equation.

Due to the difference of the physical and chemical properties between the normal paraffin and the isoalkane which have the same molecular weight,they are affected by the physical and chemical property of soil substrate and other external environmental factors and are hence likely to have some differentiation effects during migration,rendering their distribution in space characterized by some signature and regularity.Isomerization rate indicators φ_iC4 /φ_nC4 and φ_iC5 /φ_nC5 can expose to some extent the characteristics and regularity.With the isomerization rate indicators φ_iC4 /φ_nC4 and φ_iC5 /φ_nC5 ,we can determine organic maturity,path and direction of light hydrocarbon migration and light hydrocarbon generating environment,and study biochemical degradation of light hydrocarbon.

The overburden 200 m thick in Galinge area makes it hardly possible to carry out geological work, and the limited drilling work has added difficulty to the deep ore body exploration. Based on previous work, the authors employed wavelet transform to analyze the plane magnetic anomalies and found that the details at 1st scale and 2nd scale of the wavelet highlights the characteristics of a fault in the vicinity of Line 3. Meanwhile the 2.5D inversion method applied on Line 3 showed that the fault does exist, and this has later been confirmed by drilling. Besides, the authors found that the 4th detail of wavelet analysis is a regional anomaly, whose depth might be 456 m below the surface. It is thought that there may be no magnetite body below the depth of 456 m. The authors also conducted forward calculation for Line 5 located in the anomaly center, and found no residual anomaly, suggesting the nonexistence of hidden deep ore bodies. The authors have obtained a deep understanding of the geological conditions by application of wavelet multi-scale analysis and 2.5D inversion method to the magnetic anomalies, and this approach can provide the strongest evidence for further drilling work.

The present paper makes a brief description of the progress of several main electric methods which havebeen developed quite rspidly since 1980's.They include induced polarization method,frequency spectrum IPmethod,trandient electromagnetic method, controlled-source audio-frequency magnetotelluric method and GPR.

A soil gas radon survey was performed on a large scale to determine the distribution of radon in soil of Zhuhai City in Guangdong Province by means of a portable radon monitor of a semiconductor alpha spectroscopy. The survey sampled 469 sites covering an area of more than 100 km². The average of soil radon concentration in the soil depth of 0.6 m is 55.94 ± 58.54 kBq/m³ in Zhuhai urban area, whereas the concentration is 7.14±8.75, 37.64±25.92, and 151.25±196.23 kBq/m³ in the Quaternary sediments, the mixtures of sediments and weathered grain of granite, and the weathered granite in Doumen District, respectively. The high radon potential areas are located within biotitic granites and new industrial districts, as indicated by the strong correlation between the radioactivity level and geological lithology. The mean value of soil gas radon concentration in Zhuhai urban area (ZUA) is about ten times as high as that in Guangzhou, Quanzhou and Jinjing City. The results show that Zhuhai area has higher radon potential, and hence protective measures against radon should be taken into account.

The exposed crust is the critical interface where the lithosphere interacts with the pedosphere, hydrosphere, and atmosphere. The petrogeochemical map of the exposed crust can provide essential fundamental geochemical data for investigating the distributions and cycles of elements among different spheres. However, the plotting of the large-scale petrogeochemical map of the exposed crust has been constrained by the limited data volume and mapping technology. Consequently, no such a map covering the Chinese continent is available. This study proposed an innovative mapping technology roadmap based on over 16,000 petrogeochemical data and fundamental geological information. First, the databases for petrogeochemical information, stratigraphic structure information, and spatial information of geological units were constructed. Second, the geospatial information of strata and rock masses was extracted from the basic databases. Third, the petrogeochemical information was assigned to strata and rock masses to obtain their spatial distributions and element contents. Fourth, the spatial distribution patterns of 76 elements in the exposed crust were visualized using geographical information system (GIS) technology. Additionally, this study analyzed the challenges in the mapping process, including geological information accuracy, the lack of samples for special lithologies, reliability assessment, and scope of application, finally proposing corresponding solutions. The petrogeochemical map of the exposed crust demonstrates significant application potential, providing foundational data for investigating geochemical background and rock-sediment element cycling.

The generation of batches of GPS coordination is one of the most important tasks before the performance of the magnetic field work. This paper deals mainly with the batch generation of measuring point coordinate for magnetic field work by using Microsoft Visual C++ and Mapgis. The authors successfully designed and implemented a software witch could generate a batch of GPS points for magnetic field work and successfully used it in the TonganXiaoniuchang magnetic survey project of Sichuan Province.

The main tasks of geophysical prospecting techniques in search for golddeposits are detection of or--controlling fault zonesl fracture zones and altera-tion zones, delineation of ore-bearing rock bodies and strata, determination of weak mineralization zones and search for quartz veins and other ore-bearing veins. Such traditional techniques as gravity, magnetic method, induced polari zation method and extremely low frequency electromagentic method all prove to be effective. Tests show that piezoelectric method, radio method and seis mic induced polarization method are quite promising. In addition, the study of thermoelectricity and thermoluminescent characteristics of rocks and mine rals is a new subject which deserves due consideration and will play an acti ve role in prognosis of ore resources and evaluation of ore potential.

The Laowan gold belt is located in the eastern part of the Qinling orogenic belt, between the Nanyang and Wucheng basins. It boasts super-large gold resources hosted by moderate- to low-temperature magmatic-hydrothermal gold deposits formed during the Late Yanshanian. To explore the second exploration space and achieve new prospecting breakthroughs, this study investigated the primary halo of the No.59 ore body in the Laowan gold belt. Multiple statistical methods were employed to analyze the correlations among ore-forming elements. Accordingly, reliable geochemical indicators were identified to predict deep prospecting orientations. The results show that the primary halo of the No. 59 ore body exhibits an axial zoning sequence of Sn, Ba, As, Au, Pb, Cu, Sb, Ag, Mo, Bi, W, Hg, and Zn. The front-halo element Hg appears late in sequence, positioned after ore-forming elements Au, Ag, Pb, and Cu, suggesting the presence of blind ore bodies at depth or significant extension of the known ones to a burial depth of 650 m and above. In contrast, the rear-halo element Sn appears early in the sequence, indicating that the ore body was somewhat denuded. Correlation, cluster, and factor analyses were used to investigate the affinities between ore-forming elements and other metallic elements. Strong correlations were observed among Cu, Ag, and Au, establishing them as effective prospecting indicators within the deposit area. The cumulative index ratio of front- to rear-halo elements showed an increasing trend at a burial depth of 650 m, where a well-developed and non-closed anomaly was revealed by the F2 factor score contour. This suggests promising prospecting potential at this depth and deeper parts. Based on the comprehensive analysis, this study posits that the area at and below the burial depth of 650 m in borehole ZK3041 along the exploration line 304 is an exploration target. A prediction borehole drilled north of borehole ZK3041 saw the extension of No.59 ore body at a burial depth of about 720 m. Moreover, the assessment indicators show that the ore body still holds significant prospecting potential in the deeper part.

Over the past nearly 30 years,geophysical technical standards for geological surveys have successively experienced zero standards,sparse standards,and standard series.As a result,a series of standard systems of gravity,magnetic,electrical,seismic,and radioactive prospecting have been gradually established,which play an important role in establishing standardized work procedures and promoting new methods and techniques in the field of geophysical techniques for geological surveys in China.However,with the transformation and development of geological surveys in China,the current standard systems of geophysical prospecting are yet to meet the requirements of geological surveys at present.The paper summarizes the development status of geophysical standards for geological surveys in China and explores the research direction and development trend of the standardization of geophysical techniques according to the need for geophysical methods and technologies in the transformation and development of geological surveys in China.

The artificial source electromagnetic method is an important technique for deep resource exploration. The key challenge is to improve the depth and precision of detection through innovative technology. The detection mode of electromagnetic methods is evolving from far-field to near-field, and the study of near-source electromagnetic methods has become an international research frontier in recent years. Building on the recent advancements in wide-field electromagnetic methods and multi-channel transient electromagnetic methods, the short-offset transient electromagnetic method (SOTEM) has been further developed and proposed. The distinguishing features of SOTEM are its stronger signals and wider bandwidth, which are advantageous for achieving the detection requirements of greater depth and higher precision. This special issue presents eight articles covering the methods, techniques, software, and applications of SOTEM, providing strong support for the growing need for high-resolution subsurface detection.

Four basic problems in the application of Ground penetrtion-radar are discussed in this paper:(1) the wave-impedance of electromagnetic wave transmission in strata; (2) the reflectivity and transmissivity of electromagnetic field at the subsurface of strata; (3) reflective phase and propagating velocity of electromagnetic wave in strta; (4) detection depth of the Ground-penetration radar.

To improve the detection level of municipal roads for rapid and effective municipal road collapse warning and rapid search for municipal pipe network distribution, the 22^nd Research Institute of China Electronics Technology Group Corporation designed and developed real-time three-dimensional ground-penetrating radar (3D GPR). With the real-time 3D GPR, which is based on the architecture of field programmable gate array and digital signal processor (FPGA&DSP), the institute achieved the design and implementation of several key technologies for the multi-channel high-speed acquisition system, enriching the road detection techniques and methods. The real-time 3D GPR enables high-speed acquisition of ten-channel radar data using the horizontally polarized antennae equipped with five transmitters and six receivers. The channels can be switched using high-speed switches, which operate in an interactive interpolation manner. The 3D GPR allows for up to 32 channels and detection speeds of above 60 km/h (channel interval: 2 cm). This is attributed to the switching of the antenna array using switches. The optimum antenna polarization design was verified by the comparison of experimental data from cavity- and metal-plate-based experimental sites. As a result, the optimal antenna scheme was determined. The measured results show that, compared to general LTD-2600 radar, the real-time 3D GPR boasts a higher acquisition speed and higher performance in terms of amplitude and phase, conducive to the improvement of road disaster detection technologies. Therefore, there is high market demand for the real-time 3D GPR.

The Xinfang gold deposit resides in the gold polymetallic ore concentration area in eastern Liaoning Province. Based on regional metallogenic patterns and existing exploration results, the southern part of the Yalu River fault zone, where the Xinfang gold deposit is located, shows significant potential for gold resources. As exploration progresses, more gold ore bodies are expected to be discovered in the gold deposit area. However, the lack of effective deep exploration techniques limits further exploration and exploitation in the area, failing to effectively reveal the extensions of lithological boundaries and the distributions of fault structures in the area. This study presented the first application of the wide-field electromagnetic method in the area. Based on the obtained results and geological engineering information, this study delineated the electrical layers within a depth of 3 km, determining the thickness of the Neoproterozoic cap rocks and inferring several fault zones. Combined with existing geological data, this study identified the low-resistivity anomaly zone at a depth of about 1 km as an extensional structural plane caused by ductile shearing. Overall, this study provides valuable geophysical data for establishing a geological prospecting model for eastern Liaoning Province, holding significant research value for geological and mineral exploration in the area.

The 3D directional borehole radar system can perform 3D mapping for the surroundings of a borehole with high resolution. The detection of the distance from the borehole and the angle in relation to the magnetic North can be completed in a single borehole. The system has many advantages over the 2D borehole radar in such aspects as high resolution, rapidness and great penetrating depth. The authors deal with the working and imaging principles and technical specifications of the 3D directional borehole radar in details and, combined with field data, show its true application results.

In this paper, recent advances in the research and development of quantum magnetometers have been described together with some suggestions on further research work.

To identify areas potentially rich in metal minerals, this study proposed a prospecting method based on tectono-geochemistry weak information extraction. After the exploration scope was determined, sampling points were arranged using a grid pattern, followed by chemical tests on the collected samples. Through static extraction, centrifugation, and dynamic extraction, weak tectono-geochemical information in the samples was extracted. Then, the distribution of metal minerals within fault zones was analyzed based on the extraction results, and thus metal mineral prospecting was completed. During the geological exploration in the Wuminggou-Baidungou area in the Wulonggou, Dulan County, Qinghai Province, the mineral structures within the exploration area were analyzed using extracted weak tectono-geochemical information. As a result, among the 17 fault zones identified, a 500 m long metal ore body was delineated in fault zone Ⅳ, six ore bodies with lengths ranging from 180 to 400 m were determined in fault zone Ⅵ, and two ore bodies with lengths ranging from 550 to 800 m were delineated in fault zone Ⅺ. The remaining ore bodies were identified as blind ore bodies. The application of tectono-geochemistry weak information extraction for metal mineral prospecting yielded significant achievements, meeting the practical needs of metal mineral exploration. This method can be widely applied to metal mineral prospecting in similar geological settings.

Multi-channel transient electromagnetic data suffer seriously from cultural noise, and removal of periodic cultural disturbance has been a major problem in the multi-channel transient electromagnetic method. In some cases with only quite a few power lines configured regularly, the power line interference can be reduced by exchanging the receiver and source. The method by reversing source current polarity then stacking them period-by-period works better for step-current source. When only homogeneous earth is considered, the perpendicular electric component, which is in fact noise, can be measured and then subtracted from the in-line electric component. Digital recursive notching is a relatively robust way in which the periodic noise can be suppressed. It is well known that recursive notching is very fast; however, holes resulting from pre-deconvolution notching and transient response of digital recursive notcher has to be highly regarded. In this paper, several key points in removal of periodic power line noise in multi-channel transient electromagnetic data using digital recursive notch are studied. First of all, a modified version of so-called zero-pole digital recursive notcher design method, where filter coefficients are evaluated from notch width that makes significant physical sense and make analysis more clear, is proposed. After that, research on post-deconvolution notching, which directly deals with earth impulse response, is conducted. In addition, factors influencing transient response and notch result, such as notch width, initial conditions, and shape of earth impulse response, are analyzed. The results indicate that appropriate selection of initial conditions can effectively reduce the transient response of digital recursive notcher and thus remove periodic noise in earth impulse. Finally, reasonable result is obtained by applying the post-deconvolution digital recursive notch to real field data.

During the exploration of the underground medium structure, the gradiometer as well as its new deployment styles for various applications has become an important research topic of world concern. This paper describes various kinds of gradiometers based on torsion balance and difference algorithm and deals with the principle of each instrument. In addition, the absolute gradiometers based on the laser and atom interference are also described. In the last part of this paper, the design of the measurement light path is presented. The results obtained by the authors can serve as the technologic reference for developing gradiometer.

Over the past century, electromagnetic exploration technology has evolved from direct current resistivity and induced polarization methods to a comprehensive geophysical system. Yet, in China's new mineral exploration phase, challenges like deep-mining needs, cultural noise, and weak 3D interpretation limit traditional methods. High-power-ultrahigh-power electromagnetic technology, by boosting transmission current, combats these issues. It enhances detection depth, enables 3D exploration, and drives technological and application innovation. This paper reviews the development of high-power-ultrahigh-power electromagnetic instruments and current research. It emphasizes that technologies like true 3D full-waveform IP collection and inversion, tensor CSAMT collection and inversion, and multi-parameter joint inversion of time-and frequency-domain EM methods can strengthen deep-target detection. Future research should tackle anisotropic 3D inversion, full-domain inversion with a field source, and extracting polarization and magnetization rates under complex constraints. These advances will propel electromagnetic methods toward greater depth, precision, and intelligence, supporting China's renewed mineral exploration efforts.

The requirements for the design and manufacturing of nodal devices are relatively low. The most basic modules of a nodal device include controllers, acquisition circuits, GNSS timing circuits, geophones, batteries, interfaces, downloading cabinets, data downloading & compositing servers, optional testing circuits, signal generators, and QC manuals. As mature supply chains are available for all the above modules, manufacturers pay more attention to organically integrating the above modules into products that can stably work and meet the needs for the signal acquisition of seismic exploration. However, the absence or neglect of some details in some products on the market due to design or cost considerations will cause difficulties in the field application of seismic data acquisition. The data acquisition quality of the nodal devices relies entirely on the independent performance and stability of each nodal device, which further rely entirely on the manufacturers’ understanding of signal acquisition for seismic exploration and data acquisition operations and the resultant design. The requirements of oil and gas exploration and development in new situations must be considered in the design of nodal devices. The focus of oil and gas exploration and development is constantly shifting to deep and ultra-deep parts with more complex ground surfaces, and thus high precision and resolution are required for signal pickup. As a result, nodal devices should be more capable of acquiring weak signals and broadband signals, which cannot be compromised in the design. This paper elaborates on the fundamental details of signal acquisition, test functions, circuit design, storage, batteries, profile, auxiliary systems, quality control, and auxiliary devices in order to avoid problems such as signal distortion, coupling, and EMC.

This study performed forward modeling for the short-offset transient electromagnetic (SOTEM) responses of a three-dimensional geoelectric model using the three-dimensional finite-difference time-domain method. The results reveal that: (1) The attenuation curves of the E_x responses from the electric field above the goaf or collapse column were above the background response curve at early times but below it at later times; (2) A shorter offset corresponded to a higher relative anomaly of ∂B_z/∂t response signals. Increasing the length of the transmitting source could enhance the signal intensity while slightly decreasing the relative anomaly; (3) In the case of survey lines close to the transmitting source, the overall ∂B_z/∂t responses of the goaf or collapse column were weaker than the background responses. For survey lines away from the transmitting source, the overall ∂B_z/∂t responses of the goaf or collapse column were stronger than the background responses. In summary, the calculation results demonstrate significant implications for understanding the ability of the SOTEM method to detect typical water-rich bodies in coal mines, laying a theoretical foundation for the parameter selection of SOTEM devices and their generalized application in the coal sector.

This paper makes a generalized description of the scientific and technical advances in magnetic prospecting in China, which include such aspects as gro und magnetic survey, acromagnetic survey, marine magnetic survey, magnetism of rocks, paleomagnetism, absolute measurement of geomagnetic field. data pro cessing and interpretation of magnetic anomalies, and development tendency of this field.

Based on such characteristics of the contact metasomatic skarn copper deposit as strata, intrusive bodies, ore-control structure, alteration zones and mineral geology and geochemistry, in combination with element associations, primary anomalies and zoning regularity of element anomalies, the authors have summed up three kinds of geochemical exploration criteria for the skarn deposit, i.e., rock body evaluation, erudition degree and concealed ore prognosis, which provide scientific basis for the exploration of this kind of ore deposits.

The thin interbedded sand bodies in the W oilfield of the South Turgay Basin,Kazakhstan,exhibit rapid lateral variation and poor connectivity.For many years,the application of conventional reservoir prediction methods has yielded unsatisfactory results,and unclear insights into the horizontal and vertical distribution characteristics of favorable reservoirs have severely constrained the oilfield's exploration and development.To address these challenges,this study adopted an integrated approach incorporating forward modeling,post-stack seismic processing,and multi-attribute fusion to develop a prediction methodology suitable for the geological conditions of the study area.Based on forward modeling that established the relationship between reservoir variation and seismic waveform changes,empirical mode decomposition and blue filtering were applied to enhance the dominant frequency and resolution of the seismic data.The multi-attribute fusion of waveform indication inversion results,root-mean-square amplitude,and instantaneous frequency ultimately delineated the distribution and thickness of the target sand bodies.The results demonstrate that this method effectively predicts the distribution and thickness of favorable sand bodies,with errors of less than 2 meters compared to drilled thicknesses across the field.The spatial distribution of reservoirs is consistent with geological understanding.This study provides valuable guidance for subsequent rolling evaluation and efficient development of the oilfield.

This paper has summed up the development and new application of ground-searching radar in recent years. Based on detailed analysis of the principle and system structure of ground-searching radar, the authors put forward the train of thought for improving system structure of ground-searching radar and, aimed at solving the great noise existing in ground-searching radar work and the inadaptability in transplantation of seismic data-processing technique, raise a new scheme for underground interface high-resolution imaging of ground-searching radar.

On the basis of achievements obtained in surface rock survey and borehole primary halo studies performed in the Zijinshan copper-gold ore district, the present paper has discussed in detail horizontal and vertical anomaly distribution characteristics of halo-forming elements in the ore deposit, determined main ore-forming elements and associated elements, calculated zonal sequence of elements, expounded zonation of anomalous elements and, based on super-orehalos, be low-ore halos and element zonation and using multiplictive ratios, formulated Criteria for evaluating denudation level of copper and gold ore zones. These data. combined with geological characteristics of the ore district and ore deposit. have led the authors to establish the geological-geochemical prospecting mo del of the Zijinsban ore district. In geocbemical exploration conducted on the outskirts of the roe district. economically valuable orebodies and new mineralization types (porphyry gold, copper and molybdenum ores) were discovered, thus laying a foundation for the development of the Zilinshan district into a large-sized copper deposit.

The implied contour level and color scheme in Surfer software fail to express the subtle difference of DEM and the effect

of color solid. In addition, the artificial setting of the levels and color values are timeconsuming and laborious, and the

results are sometimes not perfect. With the consideration of contour level and color scheme and on the basis of Surfer platform

automation technology, this paper presents a program that can automatically generate a level file with different intervals and

different colors, thus resulting in satisfactory effect and efficiency.

Selenium (Se), one of the trace elements essential to human body, plays an antagonistic role toward the toxicity of heavy metals. The most important, safe, and feasible way for human body to take Se is to transform Se via food chain. This study collected and analyzed 30 groups of samples of rice seeds and corresponding root soil from the natural high-quality Se-rich farmland that is widely distributed in Libo County. Based on this, this study evaluated the edible safety of rice, studied the selenium content in the rice-root soil system, and investigated the influence of the physical and chemical conditions of soil on rice's absorption and transport of selenium, aiming to provide a scientific basis for the development of Se-rich agriculture in the study area. The results are as follows. Most root soil of rice in the study area is Se-rich, with an average Se content of 0.41×10^-6. The rice in the study area has an average w(Se) of 0.030 7×10^-6, and green and safe rice accounted for 70%. For the root soil of rice in the study area, there is a significant positive correlation between w(Se) and w(Fe₂O₃), w(Al₂O₃), w(MgO), and w(organic matter), and there is associated relationship between w(Se) and some heavy metals including Cr and Cd. There was a significant positive correlation between Se content of rice seeds and that of root soil. By contrast, there is a significant negative correlation between the Se enrichment coefficient of rice and the contents of Se, As, Cd, Cr, Hg, Ni, Al₂O₃, Fe₂O₃, and organic matter in root soil. The results indicate that the absorption and fixation of Se by the organic matter and Fe-Al oxides in soil reduce rice's absorption and utilization rate of selenium. The negative correlation between Se enrichment coefficient of rice and the heavy metal contents of root soil suggests that Se may play a certain antagonistic role toward the absorption and transport of heavy metals in the soil-rice system. The study area is rich in Se-rich farmland resources, yet there is a risk that the contents of Cr and Cd in rice slightly exceeds relevant standards. Therefore, it is necessary to pay attention to the ecological effects of heavy metal elements in the development of Se-rich agriculture in the study area.

Located in Guixi County, Jiangxi Province, the Lengshuiken?silver deposit is thelargest silver deposit in China, genetically belonging to porphyry type. Based on geological andgeoohemical characteristics of the ore deposit, thisjpaper has emphatically studied the distributionof trace elements in the ore deposit, tentatively fonnulated a geochemical prospecting model forthis ore deposit, and predicted the prospects of its development.

This paper deals with the development of three-dimensional seismic exploration in the coal departments of China in such aspects as designing, acquisition, processing and interpretation techniques as well as the achievements made in recent years.

The concept of deep penetration exploration geochemistry is proposed by the author based on the latest advances of geochemical methods for deeply concealed deposits. Deep penetration exploration geochemistry, a new branch of exploration geochemistry, involves the measurement of any direct geochemical information emanating from the deeply concealed deposits. Its purpose is to find deeply concealed deposits by employing newly recognized geochemical methods which can penetrate thick overburden. Abrief description of its research scope and necessity is given in this paper.

In the tentative mercurometric survey around the Qin Shi Huang Tomb, a high mercury anomalous area was detected over the tomb. This suggests that there does exist a mercury source at the depth, and that the area of the mercury anomaly might reflect the approximate position of the underground palace. The heat-release mercury study demonstrates that the soil mercury over the Qin Shi Huang Tomb is basically composed of low-temperature mercury, and that soil survey measurement is actually the reflection of low-temperature mercury. The volatile mercury in soil is consistent with the soil mercury; nevertheless, the soil mercury is more stable. Theα-cup radon measurement has yielded preliminary results in the detection of underground mercury source and the locating of subordinate funeral pits.