In the light of typical coneshaped columns in the Lu'an mine of Shanxi Province, the authors

established a mathematical model for the collapse column, and used the wave equation model for

seismic ray tracing and wavefield simulation of collapse columns. The simulation results show that,

due to the special nature of the collapse columns, such waves as the normal reflected wave, the fault

point diffraction wave, the delay diffraction wave, the delay reflected wave and  the "diffraction

wave" consisting of Pwave field are formed around the collapse columns. On such a basis, the field

shot was simulated, and then a single shot record for routine processing  was generated to produce

stacking sections and migrated sections. The forward section and the actual data analysis reveal that

the fallen columns of the special wave constitute an important feature for recognizing collapse

columns; nevertheless, the resultant scale of the actual seismic data interpretation is often smaller

than the scale of actual collapse column. Some suggestions are also put forward for reference.

Low density geochemical survey in Yishenjilike mountain area led to the discovery of a huge gold geochemical block, and the verification and evaluation of gold anomalies led to the discovery of the Bogutu gold deposit. In combination with the geological characteristics of the prospecting area, the authors carried out a series of geological-geophysical-geochemical exploration work, delineated quite a few geochemical and IP anomalies, and detected the characteristics of ore-bearing structural belt. Through trenching and drilling verification, the authors found more than 40 gold orebodies, thus achieving good ore-prospecting results.

The existing geological data show that there are several buried faults in the main urban area of Chengdu. However, the specific location and distribution of these faults are still unclear, which poses great security risks to the comprehensive and scientific exploitation and utilization of underground space resources and the optimization of urban construction planning and layout in Chengdu. In view of such a situation, four geophysical methods, namely, micromotion survey, high-density electrical method, transient electromagnetic method and soil radon measurement, were used in this paper to comprehensively explore the buried Baojiangqiao fault in the work area. The integrated geophysical prospecting methods not only identified the stratigraphic structure along the survey line, but also obtained the location, property, attitude and scale of the buried Baojiangqiao fault. This work indicates that the integrated geophysical prospecting methods can achieve better results in the exploration of urban buried fault.

A review on the airborne gravity survey and airborne magnetic survey are given in this paper. The

authors hold that these techniques have entered into a new development period, as evidenced by the

emergence of such technologic indicators as airborne vector magnetometry, magnetic fulltensor LTSSQUID

and HTSSQUID gradiometry, airborne gravimetry, gravity gradiometry and geophysical survey by UAV.

This paper gives a brief review of the history of the airborne gravimetry. Based on the principle of the airborne gravimetry, the paper deals emphatically with the history, the present  research situation and the developments of the airborne scalar gravity survey system. Further development trends are also indicated.

 With powerful Matlab image processing functions, this paper has realized the 3D display of ground penetrating radar data, whose procedures are simple to prepare and easy to learn. A detailed description of the code is given, and the three-dimensional test data show that, by setting transparency, the target can be displayed in an intuitive and visual way.

This paper puts forward a new method for calculating anomaly area—the polygonous approximation method,and gives corresponding algorithm and precision controlling technique.With this method,one can calculate anomaly area rapidly and precisely,thus yielding relatively satisfactory results.

In drawing the contour map of geophysical data, suitable gridding methods should be chosen according to objective

environment characteristics and characteristics of data themselves. With practical examples, this paper deals with some common

gridding methods such as inverse distance to a power, Kriging, Minimum Curvatrue, Nearest Neighbor, Polynomial Regression, Radial

Basis Function, and Triangulation/Liner Interpolation, probing into their choosing means, applicable fields and parameter

installment.

The R-mode cluster analysis is a mathematic statistical method for obtaining the quantitative similarity of several elements. Its procedure includes: the conversion of the original data; the solution of the relevant coefficient ; the clustering of the result. The above operation can be realized by using the data analysis tool of Excel. This method is quite suitable for field utilization.

IP is an important method for mineral resources exploration, but it can only be applied in a few pivotal places because its difficult performance, and hence the information obtained from the survey area is very limited. The aim of this study is to find a simple and effective IP method with which we can get much valuable information form the survey area so as to improve the exploration effect. In the Yinan gold ore district, the authors applied the gradient sounding profile method, calculated 2D resistivity and obtained the IP model. The results show that the gradient sounding profile method is simple and effective.

This paper has described and reviewed the pinciples,expermental set up and observational results of applying atom interferometer to measuring the earth's gravitational acceleration.This method was developed by Nobelist Steven Chu,M.Kaservich,A.Peters et al.,who demonstrated a resolution of 10^-10.The application of this technique to geophysics and the related problems are also discussed.

As an important prospecting technique and an effective means for obtaining mineralization data,

geochemical exploration has been proved to be very successful in mineral exploration. This paper focuses on

commenting the present research situation and application effect of some new methods such as structural

superimposed halos method, heat released mercury method, separatory electrogeochemistry method, enzyme leach, and

geogas and selective leaching of mobile metals method. It is emphasized that any one of these methods has its

unique applicability and that, in the practical application, we should pay attention to the cooperation of

geochemical exploration, geologicalgeophysical exploration and remote sensing and depend on the study of

geological background so as to demonstrate the usefulness and effectiveness of geochemical exploration.

Element abundances of the continental crust and rocks cited in the past and recent literature have been based on compilations of data from various studies. This leads to uncertainties in sample representativeness and data quality. The present study is based on systematic collection of 28 253 individual rock samples over an area of 3.3 million km² in eastern China, east of eastern longitude of 105°.The sampling involves more than 800 igneous intrusive bodies and metamorphic complexes as well as more than 500 type stratigraphic sections. From the individual rock samples, 2 718 composite samples were made and analyzed for 77 elements by 15 specific methods, dominantly XRF and INAA. Analytical quality was controlled by international and national preliminary geochemical reference materials of GSR, GAu and GPt series. Synthetic results from geological, geochemical and geophysical studies were used to construct crustal constitution model, from which element abundances of the continental crust in the North China platform, the upper crust and exposed crust in eastern China, chemical composition of igneous rock in China and of sedimentary rock and metamorphic rock in eastern China were derived.

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

According to the data obtained from air-borne electromagnetic and magnetic survey and

ground two-frequency IP and magnetic survey, this paper discusses the relationship between the

features of air-borne and ground geophysical composite anomalies and the ore resource distribution.

On the basis of an integrated analysis, geophysical composite anomaly criteria in search for iron, zinc

and lead deposits were established, and 12 important ore-prospecting targets were delineated, which

provides very important clues for finding iron, zinc, lead and some other ore resources.

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.

Based on two-dimensional Fourier transform and half-wave theory, this paper has studied the seismic Rayleigh wave dispersion curve extraction in f-k domain and made this theory fit in with a program by means of Delphi7.0. It is concluded that the f-k method overcomes the shortcomings of the one-dimensional digital processing technology and makes full use of multi-channel Rayleigh wave data record.

 Numerical integration of Hankel transforms is effective tools for EM Sounding 's forward numerical simulation, this paper made out formula derivation of numerical integration of Hankel transforms by digital filtering, and use digital coefficients to do numerical compute which was put forward by Guptasama and Singh，finally contrasted to theoretical resolve expression and analyzed this algorithm's error distribution. The results show that the calculation of this algorithm continuously approximate its theoretical solution, it has no oscillation, high precision and great practical value in the numerical simulation study.

 Vibroseis exploration, as an important method of seismic exploration, has become increasingly valued by geologists. During the field work, different geological conditions need different parameters, and the choice of suitable excitation parameters has become a very important problem. This paper mainly introduces six kinds of parameters, namely numbers of controlled seismic source, scanning bandwidth, vibration period, scanning length, scanning slopes, and vibration rate. The influence of these parameters on the quality of seismic records was studied in detail, and the simulation of the proper parameters was performed in Jiulishan area to enhance the resolution of vibroseis exploration and improve the signaltonoise ratio of seismic records.

This paper has put forward the idea of utilizing Surfer to draw the initial data profile-plan. The programme compiled can realize the construction of Bln file. The profile-plans for regular net and irregular net have been constructed, and the results are satisfactory.

Migration velocity analysis and migration imaging constitute two important parts in seismic data processing. At

present, time migration has become mature, and depth migration is getting more and more perfect. The common method for time

domain migration imaging is pre-stack time migration. By adopting stacking velocity analysis along the layer, exact layer

stacking velocity can be obtained. Through dip correction, pre-stack time migration and CRP de-migration velocity analysis, the

velocity is optimized step by step, and then a desired RMS velocity field that is up to the geological rule is acquired. In

addition, the method for building the accurate migration velocity field is summed up through the study of the depth migration

method. A new seismic data processing flow in combination of Kirchhoff arithmetic based on ray tracing and wave equation

arithmetic based on wave field extrapolation is presented. As a result, migration velocity analysis and migration imaging are

considerably improved.

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.

On the basis of accurate analysis of 154 composite soil samples collected from various landscape in China and other reference information, abundance of 79 elements and composition of soils in China have been given, chemical composition of soils under the influence of matrix rock and supergenesis geochemistry condition have been studied preliminarily.

On the basis of mote than230 English and Russian papers or monographsissued in the last 30 years as well as nearly 50 Chinese articles published overthe past 10 years on the inversed problem in g avity and magnetic explora-tion, combined with his practice in the study of the inversed problem, the all-thor expounds the inversed methods in gravity and magnetic exploration cur-rently used both at home and abroad, briefs the readers about the researchsituation in China and foreign countries, and makes a detailed review on achi-evements gained in China in comparison with the research levels abroad.Final-ly, suggestions are put forward concerning some subjects which are worthnoticing in future research work.

This paper proposes an equivalent second order elastic wave equation to solve the problem of being unable to completely

separate the coupled P and S wave by full elastic wave equation. Through solving this equivalent wave equation by high-order

staggeredgrid finite difference scheme together with Flux Correction Technology (FCT) and separating wave fields of the

isotropic model and layered model, the authors accurately obtained the hybrid wave field and completely separated fields of pure

P wave and pure S wave fields. An analysis of the numerical results shows that the method is effective and reliable in isotropic

media, and there exists abundant energy transform information in separated pure P and pure S wave field. The result of the study

is of significance in understanding the propagating law and the elastic wave theory in the complex wave field.

The algorithm of the finite difference oforder velocitystress staggered grids has been built, which is

suitable for the perfectly matched layer (PML) absorbing boundary for elastic media. Meanwhile, the construction of the

PML absorbing boundary condition and the realization of the finitedifference algorithm are discussed in detail. Wave

field modeling calculations show that, compared with the conventional decaying exponential absorbing boundary and non

absorbing boundary, the PML absorbing boundary can perform absorption much more clearly and absorb the boundary

reflection from various angles, whose absorptivity (the ratio of absorption energy to unabsorbable energy) can reach

99.99%. The PML absorbing boundary can well eliminate the periodic folding effects, which makes the calculation of the

wave field characteristics very distinct, and the Rayleigh wave can be clearly shown in the waveform record.

The development of the gravity gradiometer is described simply in this paper, and the measuring principle and development experience of the rotating accelerometer gravity gradiometer are emphatically discussed. On the basis of researches on the existing airborne gravity gradiometer, the prospects of the airborne gravity gradiometer are also presented.

With the extensive adoption of computer technology in geology and geophysics, computer graphics becomes more and more important. For the purpose of improving quality and efficiency, several software should be combined in practical work. In this paper, some basic characteristics of Surfer and MapGIS are discussed, and their application in geological field is described from the angle of geological mapping, thus drawing forth the necessity of the conversion between Surfer and MapGIS. The general method and steps for the conversion of maps between Surfer and MapGIS are presented in detail, and several problems concerning the conversion and corresponding solutions are emphatically discussed.

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.

In the light of the characteristic time-frequency properties of different time-frequency analysis methods, it is

important to select an optimal time-frequency analysis method for high precision seismic exploration in the coal field on the

basis of comparing and studying these methods. Aimed at probing into STFT, Wavelet Transform, S-Transform, Choi-Williams

Distribution, Wigner-Ville Distribution and its improved methods, this paper studied advantages and disadvantages of every method

through numerical simulation in time resolution, frequency resolution and interference. The First Break Picking and Separate

Frequency Display for Collapse Column interpretation were realized by SPWVD and S-Transform, with a good result obtained.

 Basic principles and techniques for the shallow seismic refraction wave method and the highdensity resistivity method

are described in this paper in combination with engineering practice to explain the results of the refraction wave method and the

high-density resistivity method in railroad and highway tunnel exploration. The application effects of the combination of these two

methods in detecting positions, sizes, natures and characteristics of such harmful geological bodies as concealed faults and shatter

zones are also discussed. Some measures for improving the investigation accuracy of these two methods are put forward.

This thesis supply a profile about performance of TerraTEM system and the  distinguishing feature of TEM. By exploring

work on two conceal iron deposit in HeNan province and analyzing. the abnormal value of the TEM system.combining with drill

drawing,The writer prove that the TEM can take a obvious effect on exploring iron mineral.

The main minerals in the Yiliu polymetallic ore district are mainly As, Sb, Pb, Zn, Ag, W, Sn, Nb and Ta, the deposit types and the ore-controlling factors are complex and diverse. Recently, by using 1:50000 geochemical stream sediment survey, geochemical soil survey and CSAMT method in this ore district, supergene distribution of elements were found, and many integrated anomalies were delineated. A comprehensive evaluation of all kinds of anomalies shows that the F3 fault has features of ore-passage structure and ore-storage structure, and the area sandwiched between F2 and F3 fault are favorable ore-forming place, whereas the depression parts of biotite granite which have high resistance and multiple sets of fracture intersections are most favorable places for mineralization.

The authors made statistic calculation of stream sediment data using such means as traditional statistics, robust estimation，cumulative percentage of 85% and multifractal statistical method in Chabaqi area and compared the thresholds obtained by the four methods. The thresholds of the same elements obtained by the four methods are obviously different from each other. The thresholds calculated by the cumulative percentage statistics are lowest except for lead, and the thresholds calculated by the other three methods fail to show obvious regularity.The results are closely related to the distribution characteristics of the geochemical data and the statistical methods used. Comparing the anomaly characteristics with the geological characteristics, the authors have found that, although weak and gentle geochemical anomalies will be mostly detected by cumulative percentage of 85%, the larger anomaly areas will bring difficulties to anomaly inspection in the field. It is therefore thought that the thresholds obtained by multifractal statistical method are suitable for the study area. A comparative study of the thresholds has led the authors to believe that the reasonable method must be combined with the actual geological conditions and based on a thorough study of the geological background of the study area.

With practical examples, this paper deals with the basic principle and technique of the Rayleigh surface wave exploration, the technology for its application to railways, the data acquisition, processing and interpretation, and the calculation method for converting the velocity of the Rayleigh surface wave to the bearing capacity. The reliability of applying this technique to railways is also pointed out.

In this paper, the working principle of three satellites (CHAMP, GRACE and GOCE) has been described, and the important geopotential models and the newest geopotential models (EIGEN-CG01C, GGM02) have been introduced.

The environmental pollutant has the same lead isotope composition as its source, and hence we can determine the accurate contaminative source through the study of lead isotope composition. In recent years lead isotope tracing has been playing its unique role in studying the source and migration of heavy metals in soil. As Tl and Pb have similar geochemical characteristics, the distribution and migration of Tl in the surface soil of the Yunfu pyrite mine have good correlation with Pb. In this study, therefore, the element and lead isotope tracing was used to study the migration of thallium in soil. Element and lead isotope tracing shows that thallium pollutants are mainly accumulated in top soil of about 0-16.5 cm, and that the soil is subjected less pollution in deeper soil. The soil around the slags at the depth of some 44 cm is affected by Tl leaching from the slags.

In the light of the pulse width of the radar wave, this paper deals with the difference and the relationship between the vertical resolution and the transverse resolution of the ground-penetrating radar, indicates the influence of the noise upon the resolution and, with practical examples, points out that the digital handling of the signal can greatly improve the resolution of the radar.

The northeastern margin of the Linyi uplift is located at the eastern end of the Luxi Block and immediately adjacent to the Yishu fault in the east. The main structural framework of the study area is controlled by the NE-trending Tangwu-Gegou fault and the NW-trending Mengshan fault. Covered by the Cenozoic sediments, the boundaries of main tectonic units in the study area are almost all concealed, and it is necessary to further investigate the change in the strike of the eastern end of the Mengshan fault as well as the distribution of the angular unconformity along the northern boundary of the Linyi uplift. Using the latest 1:50,000 high-precision gravity data, this study mainly investigated the positions and intersection relationships of the boundaries of tectonic units based on the qualitative analysis of gravity field, the interpretation of multiple gravity potential field conversion, and the division scheme of geotectonic units in Shandong Province. The analysis results are as follows. The Mengshan fault at the junction of the Mengshan uplift and the Pingyi sag transitions from the NW trending to nearly-EW trending in the east of Bancheng Town, significantly cuts the NE-trending Tangwu-Gegou fault, and shows a NW-trending turn to the east again. The angular unconformity at the junction of the Linyi uplift and the Pingyi sag neither ends in the Mengshan fault in the north nor turns southward but extends to the Tangwu-Gegou fault in the east. This unconformity also controls the southern boundary of the Pingyi sag, making the NW-trending banded gravity anomalies of the sag turn eastward. Consequently, the boot-shaped low-value gravity anomalies were formed in the study area. Based on the high-precision gravity boundary identification, this study determined the fault system and tectonic division of the northeastern margin of the Linyi uplift, providing high-precision gravity data for the basic geological study in the study area and laying a good foundation for further mineral geological survey.

This study summarized the progress and major application performance of gravity and magnetic techniques for onshore hydrocarbon exploration in China in recent years.By combining the research results of the authors,this study elucidated the new progress made in the gravity and magnetic techniques for hydrocarbon exploration from the prospect of acquisition,processing,interpretation,and application and sorted the application performance of these techniques in key fields including deep targets,complex areas,and volcanic rocks.Moreover,this study future analyzed the demand for the gravity and magnetic techniques for hydrocarbon exploration.By combining the new trends of gravity and magnetic exploration techniques at home and abroad,this study proposed the development direction and application prospect of gravity and magnetic techniques for oil and gas in deep strata and igneous rocks in complex areas.The results of this study show that significant progress has been made in gravity and magnetic exploration techniques,which play an important role in supporting the current hydrocarbon exploration.It is expected to develop high-precision and high-density gravity and magnetic exploration techniques and gravity-gravity-electricity-seismic collaborative innovation techniques.

The heavy metal element contents in soil affect the quality of soil environment. Their prediction using different models based on survey data is an important means to study the changing trends of soil element contents and soil environmental quality. Based on the data from 1∶250 000 multi-purpose regional geochemical surveys and 1∶50 000 land quality geochemical assessments, this study predicted the contents of five heavy metal elements in the soil of the study area in 2027 using the single-period incremental model and the input-output flux model individually. The results are as follows. The two models yielded different prediction results but consistent trends that the contents of five heavy metal elements increased to different degrees. Moreover, the single-period incremental model yielded larger increments than the input-output flux model. Among the various input channels of the flux model, Cd and Pb entered the soil mainly through dry and wet atmospheric subsidence, As and Cr entered the soil mainly through fertilization, and Hg entered the soil mainly through irrigation water. Based on the survey and prediction data of soil monitoring sites, the soil environmental quality grade was classified for these sites. The proportion of the sites for priority protection showed a downward trend, indicating that the soil environmental quality decreased year by year.

To quickly and effectively detect the hidden hazards of dams,this study proposed the microtremor B-mode ultrasound technology based on linear arrays.Most of the (earth) dams also act as highways,and the vibration signals generated from running vehicles propagate along dams.Therefore,this study proposed deploying linear arrays along the dams,with the vibration propagation direction consistent with the signal receiving direction.In this way,abundant vibration sources can be provided for detecting hidden hazards of the dams.The results of this study show that the data on multiple exploration points can be simultaneously acquired using the multi-channel acquisition technique based on linear arrays,thus improving the efficiency of field data acquisition.Moreover,the influence of source differences can be avoided,and the lateral resolution and the accuracy of exploration results can be improved.The technology proposed in this study was applied to the pre-flood safety inspection of a dam in Jiujiang,Jiangxi Province.Three low-velocity hidden hazards were identified in this dam and were presumed to be the weak layers of the dam foundation and the loose media of the dam body.Practices have proved that this technology effectively counteracts the deficiencies (i.e.,low efficiency and lateral resolution) of the previous microtremor exploration.Moreover,this technology allows scanning at a spacing of 1 m or 0.5 m,thus improving the lateral resolution.This study will provide efficient and accurate guidance for dam safety management.

Karst is widely distributed in China. However, geological disasters frequently occur in karst zones due to the fragile geological environment, which seriously threatens the safety of people’s life and property and cause huge economic losses. In this study, the controlled source audio-frequency magnetotelluric (CSAMT) method and microgravity were used to extract residual gravity anomalies through the two-dimensional inversion of pseudosections and multi-scale wavelet analysis. As a result, rock-soil interfaces of karst zones and the development zones of strong karst were well divided; the locations, burial depths, scales, and spatial distribution of karst caves were delineated. As verified by drilling, the rock-soil interfaces and strong-karst development zones determined by CSAMT interpretation were roughly consistent with those revealed by boreholes, and the sizes and burial depths of collapsed karst caves that were delineated by microgravity roughly correspond to those revealed by boreholes of engineering exploration. These results show that the CSAMT combined with the microgravity method can achieve significant effects in the detection of concealed karst collapses and serves as a scientific detection method for the early warning of the prevention and treatment of potential karst collapses and similar geological disasters.

Deep metal deposits tend to be associated with heterogeneous geological bodies on different scales.Moreover,their orefields mostly lie in areas with complex geological structures,developed faults,and intense lithological changes and have complex surface conditions and structures.As a result,the seismic data of metal deposits frequently originate from complex and variable seismic wave fields suffering the mutual inference of multiple types of waves.Therefore,the seismic data have extremely low signal-to-noise ratios,which severely restricts the seismic interpretation of metal deposits and the prediction of concealed orebodies. With the 2D seismic data of the Chaganhua molybdenum orefield in Inner Mongolia as a case study,this study explored the key techniques for the seismic data processing of deep metal deposits.Specifically,this study analyzed the characteristic of seismic data of the Chaganhua molybdenum deposit and summarized the difficulties with seismic data processing of the metal deposit.Based on these,this study developed a set of processes for the data processing of the Chaganhua molybdenum orefield.The actual processing results agree well with the known orebody distribution in the geological borehole section.To be specific,zones with thick ore bodies generated strong reflected energy,while thinner ore bodies exhibited low-amplitude reflected waves.The results of this study can provide strong support for inferring geological structures and delineating concealed orebodies in the study area.

The edge depth of geological body plays a crucial role in the semi-quantitative interpretation of gravity and magnetic potential field exploration. At present, the main inversion methods of geological body edge depth mainly include Werner deconvolution method, analytical signal amplitude method, local wave number method, Tilt-depth method, Euler deconvolution method and curvature attribute inversion method. These methods all have problems of solution selection, stability and adaptability. This paper mainly studies the adaptability of different types of data and models. Through basic principle analysis and model test, the results show that Werner deconvolution method and Euler deconvolution method are applicable to the most types of data sources, followed by curvature attribute, and Tilt-depth is the least; Werner deconvolution method, Euler deconvolution method and curvature attribute methods can adapt to many models, the Tilt-depth is least. For gravity data, the analytical signal amplitude of the first vertical derivative as the data source is applicable to all methods. For magnetic data, the analytical signal amplitude as data source is applicable to all methods. At the same time, it is suggested that other scholars should follow the following principles when using these methods to invert the edge depth of the two-dimensional body: It is recommended that Werner deconvolution is preferred, followed by curvature attribute and Euler deconvolution. The gravity data source of Werner deconvolution method and Euler deconvolution method is recommended to use the horizontal derivative of the first vertical derivative, and the magnetic data source is recommended to use the horizontal derivative. The gravity data source of curvature attribute method is recommended to use the analytical signal amplitude of the first vertical derivative, and the magnetic data source is recommended to use the analytical signal amplitude. In addition, based on the above research conclusions, some suggestions on the future research directions of the solution screening, stability and adaptability of the edge depth inversion are given.

This study explored the geothermal resources in Yueliangwan, Binhai County, Jiangsu Province using the controlled source audio-frequency magnetotellurics (CSAMT) method and the wide-field electromagnetic method. Through the auxiliary correction of near-field and transition-field curves, as well as the inversion based on the CSAMT data, this study obtained the electrical structure information of underground geothermal resources in the Binhai port. Meanwhile, this study acquired the information on the underground geometric structure using the microtremor exploration method. By comprehensively analyzing the interpretation results of three kinds of geophysical data, this study obtained the geothermal model of the study area and determined the locations of the anomalies. A geothermal well with a depth of 2 919 m was drilled in the study area, obtaining water yield of 2 171 m³/d with a water temperature of 51 ℃. The high consistency between the results from the comprehensive geophysical exploration and the geological and geothermal well data indicates that the comprehensive geophysical exploration method can improve the reliability of geothermal exploration results.

In order to meet the requirements of portable,intelligent and long-term automatic monitoring of 192 channel spontaneous potential monitor,the shortcomings of the acquisition and control equipment of current electrical exploration instruments in man-machine interaction,endurance and portability are solved.In this paper,the acquisition and control software based on Android platform is designed by combining Bluetooth,Wifi and other IoT technologies with geophysical instruments.After testing,the software function is efficient,the data transmission quality is good,the software runs stably.In the practical application of natural electric field signal detection of geological microorganisms, the performance is stable and can be monitored continuously for more than 36 h. The data acquisition accuracy is high, and the visualization effect is good, so it has strong practical application value.

Many karst fracture-vug reservoirs have been found in the Ordovician carbonate paleo-buried hills in the Lungu area,Tarim Basin.Hydrocarbons are mainly enriched in these fracture-vug reservoirs,which are mainly related to the paleo-underground river system in carbonate paleo-buried hills.The paleo-underground river system is well developed,especially in the western Lungu area.The fracture-vug reservoirs related to the paleo-underground river system have strong longitudinal and lateral heterogeneity,and ascertaining the seismic and geological characteristics of the paleo-underground river system in this area is the key to the efficient development of fracture-vug reservoirs in this area.Based on the characteristics of modern karst underground rivers and the log and drilling data of this area,this study established a geological model of underground rivers for forward modeling.The study results are as follows.The underground river system developing under the tight limestone setting showed continuously linear strong reflections on the seismic profile.The seismic amplitude decreased as the height and width of underground rivers decreased,and higher seismic amplitude corresponded to larger underground river caves and lower filling velocity.The amplitude can accurately characterize the horizontal range of the underground river on the seismic profile.Meanwhile,the frequency and phase can describe the outline of the underground river on the seismic profile,but the outline described was larger than that of the real underground river.The main channels of the underground river system were prone to be filled with mud.By contrast,the branch channels had a low filling probability and thus serve as the main areas for both the occurrence of underground river reservoirs and the hydrocarbon accumulation.

The 1∶250 000 multi-target geochemical survey shows that there is a large area of zinc-rich fluvo-aquic soil in northern Anhui Province, and the study on the distribution law, bioavailability, and influencing factors of zinc in the soil is of great significance to the development of zinc-rich agricultural industries. This study investigated the distribution characteristics, occurrence forms, bioavailability, and influencing factors of zinc in the topsoil at a depth of 0~20 cm and the section soil of 0~200 cm depth of both the fluvo-aquic soil and the lime concretion black soil in northern Anhui Province. The results are as follows: The fluvo-aquic soil has abundant total zinc and moderate available zinc, while the lime concretion black soil lacks the total zinc in general and is rich in available zinc. The total zinc in the fluvo-aquic soil is significantly positively correlated with manganese, organic matter, and phosphorus. The available zinc in both the fluvo-aquic soil and the lime concretion black soil is positively correlated with the available phosphorus and negatively correlated with pH. The zinc in the soil at the depth of 0~200 cm mainly occurs as residuals for both the fluvo-aquic soil and the sand concretion black soil. The total content of the water-soluble and ion-exchangeable zinc that is easily absorbed by plants in the plough layer of the fluvo-aquic soil area accounts for 0.29% of the total zinc content, and the content of iron-manganese oxide bound zinc accounts for 23.62% of the total zinc content. The total zinc is obviously enriched in the soil at a depth of 0~85 cm, which is significantly restricted by the phosphorus and manganese contents in the soil. The total content of the water-soluble and ion-exchangeable zinc in the plough layer of the lime concretion black soil area accounts for 0.41% of the total zinc content, and the total zinc content in the soil at a depth of 0~200 cm slightly changes. This study indicates that the fluvo-aquic soil in the study area has rich total zinc and moderate available zinc and that the available zinc content is mainly restricted by the pH of soil. Therefore, applying conditioners to reduce the pH of soil is an effective way to enhance the bioavailability of zinc in the total-zinc-rich fluvo-aquic soil.

As a fast and nondestructive geophysical exploration technique,the natural source surface wave technique performs well in exploration in a complex urban environment by extracting surface waves and other information using the natural earth vibration.This study applied this technique in an urban planning area to ascertain the distribution characteristics of the strata in the area through section interpretation,the extraction of site evaluation parameters including equivalent shear wave velocity and predominant period,and 3D visualized plotting.It can be concluded that the planning area has no concealed fault and thus has excellent site conditions.The results of this study can be utilized as an important reference for the site evaluation of similar areas.

The Baoding sag is located on the western margin of the Jizhong depression,Bohai Bay basin.It is adjacent to the uplift of the Taihang Mountains in the west,with the piedmont fault of the Taihang Mountains as the boundary.Identifying the deep structures and fine-scale geological structure of the sag is greatly significant for the hydrocarbon exploration and the survey and evaluation of deep thermal reservoirs in the sag.Meanwhile,it also facilitates the research on the characteristics of the piedmont fault of the Taihang Mountains.Since the exploration using the seismic reflection method feature high precision and high resolution in the detection of deep geological structure,this study conducted the seismic reflection-based exploration in the tectonic units of the Baoding sag and their periphery.First,high-quality original seismic records were obtained by means of explosive source excitation,long-array multi-channel reception,and high coverage times.Then,seismic reflection sections that can clearly reflect the deep geological structure and structural characteristics of the survey area were obtained using high-precision imaging data processing techniques,such as static correction,pre-stack noise attenuation,deconvolution,and offset stack.The obtained seismic sections allowed for determining the characteristics of faults in the sag and internal secondary tectonic units.Based on the angular unconformities identified in the seismic sections,the basement structural layer and the structural layers formed during the faulting stage and the depression stage of the Baoding sag were also determined,and,accordingly,the tectonic evolutionary process of the three structural layers were discussed.

The Changjiang uranium ore field is located in the south-central part of the Zhuguangshan pluton in northern Guangdong Province. This ore field holds many uranium deposits such as Mianhuakeng (302), Shulouqiu (305), and Changpai. These uranium deposits are mainly distributed along the contact parts between the Changjiang and Youdong plutons, and uranium mineralization is closely related to the Changjiang and Youdong plutons and their intrusive dykes. Previous researchers have conducted much testing on the formation ages of plutons, dykes, and deposits in the Changjiang ore field, obtaining abundant age data. This study summarized the chronological study advances of the granites, uranium mineralization, and dykes in the Changjiang uranium ore field. The results are as follows. The Changjiang biotite granite pluton was formed at 166~157 Ma (weighted average age: 160.9 Ma) during the Middle-Late Jurassic. The Youdong two-mica granite pluton was formed at 245.6~219.6 Ma (weighted average age: 232.1 Ma) during the Triassic. A variety of dykes such as gabbro diorites, hornblende diabases, fine-grained granitic rocks, and lamprophyres have developed in the study area. The dykes in the ore field can be divided into at least three categories according to their activity stages, namely Late Jurassic mafic dykes (150~145.1 Ma), Early Cretaceous acid dykes (138.6~123.9 Ma), and Early Cretaceous mafic dykes (110 Ma). The uranium mineralization of the Changjiang uranium ore field began during the Early Cretaceous and lasted until the Paleocene, showing a long time span ranging from 127 to 60 Ma. The uranium metallogenic periods include the Early Cretaceous metallogenic epoch (127~119 Ma), the Late Cretaceous metallogenic epoch (75~67 Ma), and the Paleocene metallogenic epoch (61~54 Ma). The age data are concentrated in the range of 70~60 Ma (Late Cretaceous-Paleocene), which might be the peak of uranium mineralization of the study area. The diagenesis and uranium mineralization of the Changjiang uranium ore field evolved in the order of Youdong pluton → Changjiang pluton → early mafic dykes → fine-grained granitic dykes → early uranium mineralization stage → fine-grained biotite granite dykes → late mafic dykes → second uranium mineralization stage → late uranium mineralization stage. There are six phases of diagenesis and uranium mineralization of the Changjiang uranium ore field, i.e., Triassic granitic magmatism (the Youdong pluton), Middle-Late Jurassic granitic magmatism (the Changjiang pluton), diagenesis of Late Jurassic mafic dykes (gabbro diorite dykes, 150 Ma; hornblende diabase dykes, 145 Ma), diagenesis of Early Cretaceous dykes and uranium mineralization (138.6~110 Ma), Late Cretaceous uranium mineralization (75~67 Ma), and Paleocene uranium mineralization (61~54 Ma). It is recommended that further studies should be conducted on the metallogenic chronology of uranium deposits, the geochronology of other dykes such as lamprophyres, and the uranium metallogenic mechanisms of deposits except for Mianhuakeng (302), Shulouqiu(305), and Changpai.

The Luzhou shale gas block,which is located in the southern Sichuan Basin,has undergone multi-stage tectonic evolution and has complex faults and multiple sets of vertical detachment layers,forming the characteristics of multiple stages,multiple strikes,and multiple layers.To overcome the difficulties with the tectonic interpretation of the study area,this study combined a set of seismic multi-attribute techniques,namely using seismic multi-attribute optimization and attribute fusion technique to assist fault interpretation,using structural anomaly attribute to identify microstructures,using seismic attribute slicing technique to analyze the characteristics of tectonic temporal and spatial evolution,and using multi-superposition ant tracking attribute technique to predict fracture development.Using this technique combination,this study completed the fine-scale interpretation of complex faults in the area, effectively characterized the development of microstructures,clarified the tectonic stages and distribution in the area,improved the fracture prediction accuracy,and described the development characteristics of fractures.The results of this study will provide solid data and a foundation for the next platform deployment.

This study introduced the development process, research status, and application effects of the tectono-geochemistry survey theory, and proposed the tectono-geochemistry weak information extraction method by summarizing the latest research results and understandings based on the prospecting practice in bedrock areas. Based on the contrastive analysis, this study pointed out the limitations of the conventional geochemical survey methods and the advantages of the tectono-geochemistry weak information extraction method, which was developed from the conventional tectono-geochemistry survey method. Moreover, this study systematically summarized the theoretical basis, operating conditions, deployment method, sampling principle, sampling media, anomaly interpretation, mapping, and application of the tectono-geochemistry weak information extraction method, highlighting the rationality of the deployment method, the representativeness of sampling points, the diversity of sampling media, and the validity (“yes” and “no”) of element anomalies and samples. Based on these, this study established the index system of this method. Finally, by combining the prospecting prediction of the eastern section of the Huijiabao anticline in the distribution area of Carlin-type gold deposits in southwestern Guizhou, this study concluded that the tectono-geochemistry weak information extraction method can extract the deep metallogenic weak information more effectively than the conventional tectono-geochemistry survey. It also inferred that this method has a good application prospect in the prospecting of concealed hydrothermal deposits and can be applied to the prospecting prediction of concealed hydrothermal deposits in all bedrock areas.

The copper mineralized bodies and orebodies of the Pulang copper deposit in Yunnan Province are mainly distributed in the Pulang complex porphyry body and were formed through complex multi-stage development. This study aims to detail the geophysical response and fractures of copper reservoirs and provide detailed orebody characteristics, fractures, and horizon burial depth to be referenced in the exploration and exploitation of the Pulang copper deposit. First, the borehole-log data in the Pulang copper deposit were sampled for comprehensive evaluation. Then, in combination with the drilling reports and data on partial core samples, this study analyzed the log response characteristics and fractures and identified the lithology of the Pulang copper deposit using mathematical statistics, three-dimensional cross plots, convolutional neural networks (CNNs), and fracture parameter calculation. The log response characteristics of the three major strata of quartz monzonite porphyries, quartz diorite porphyrites, and hornstones in the study area are as follows. The hornstone strata have relatively high resistivity, followed by the quartz diorite porphyrite strata and the quartz monzonite porphyry strata in sequence. The resistivity decreases significantly at the intervals with fractures occurring or at the relatively fractured intervals. The quartz monzonite porphyry strata have a relatively high charge rate (polarization rate) of up to about 10%. The hornstone strata have relatively high radioactive intensity than the quartz diorite porphyrite strata and the quartz monzonite porphyry strata. CNNs were used to identify and analyze the lithology of the three major types of strata based on log data, with an accuracy rate of 97.94%. Finally, this study identified fractures in these strata using dual laterolog data. The resistivity significantly decreases at intervals with fractures occurring and differs greatly between deep and shallow lateral resistivity. The quartz monzonite porphyry strata with a high copper grade have relatively low resistivity and relatively well-developed high-angle fractures. The results of this study are of significance for the identification of ore body characteristics and the exploitation of ore bodies in the Pulang copper deposit.

The Nanjinshan gold deposit is a typical epithermal deposit in Beishan metallogenic belt, which extends in a N-E direction to the peripheral shallow cover zone. In order to further achieve the breakthrough of prospecting in the peripheral shallow overburden area, the pilot work of motorized shallow drilling geochemical survey carried out. Based on the nature and thickness of the overburden, 126 motorized shallow drilling geochemical exploration samples are taken in the shallow overburden area using the vehicle mounted air positive circulation and three wing alloy scraper drilling or pneumatic DTH hammer drilling technology, with a sampling density of 16.8 points per square kilometer. The shallow drilling geochemical exploration methods and technologies in the shallow overburden area are further discussed, including the selection of drilling technology, sampling network, sampling materials, sample collection, etc. Soil survey was carried out in sporadic bedrock areas, and 278 samples were collected, and the sampling density was 48.77 points per square kilometer. Fifteen elements including Au, Ag, as, Sb, Hg, Cu, Pb, Zn, W, Sn, Mo, Bi, Cr, Co and Ni were analyzed. Through the above work, seven comprehensive geochemical anomalies were delineated. After anomaly investigation, six gold deposit bodies and one silver deposit body were found in the new circle in the bedrock area, and two concealed gold deposits and one silver deposit body were found in the shallow overburden area. The results show that shallow drilling geochemical survey is effective and feasible in the shallow overburden area of arid Gobi landscape in Beishan.

To explore in detail superficial paleochannels in Xiong'an New Area,this study investigated two profiles in the study area using the high-density resistivity method based on previous remote sensing.The interpretation results were verified through drilling.The distribution range of the paleochannels that was delineated using the high-density resistivity method was more accurate than that obtained from remote sensing.This study determined that the superficial paleochannels in the study area exhibit curved,tortuous,and braided planar distribution,achieving excellent application performance in the detailed exploration of superficial paleochannels.This study provided a new idea for future exploration and study of superficial paleochannels and can be used as a reference for the selection of methods used to investigate paleochannels in similar geological conditions.

The ultradeep Ordovician limestone fracture-vug reservoirs in the Fuman oilfield on the south bank of the Tahe River in the Tarim Basin is the core target area for the production capacity construction of the oilfield.These reservoirs in the study area contain massive dissolution vugs formed by the formation fracturing due to the strike-slip faulting and thus are highly heterogeneous.The low-frequency models based on conventional wave impedance inversion are built using data on horizons,faults,and logs,and thus they cannot characterize the fault-controlled heterogeneity of the reservoirs.For this reason,this study proposed an iterative inversion method constrained by fault fractured zone facies to predict reservoirs.The technical process of this method is as follows.First,the original seismic data were interpreted to obtain the attribute volumes that can reflect the characteristics of the fault fractured zones of the reservoirs.Then,the attribute volumes were proportionally fused with the initial low-frequency model and the spatial profile data of high-quality reservoirs obtained from the conventional inversion based on wave impedance.As a result,a new heterogeneous low-frequency model was formed.Using this model,multiple rounds of iterative inversions were conducted.The inversion results can truly describe the characteristics of the fault fractured zones in the heterogeneous reservoirs.The prediction results of 10 wells had coincidence rates of up to 92.86%.As indicated by the application,the method proposed in this study can improve the reservoir prediction performance and the prediction precision of fault-controlled reservoirs,thus effectively supporting the work in the study area.

This study investigated the surface soil of the agricultural land in Ruoqiang County, Xinjiang. Based on 142 surface soil samples collected in 2016, this study analyzed the selenium (Se), fluorine (F), iodine (I), Al₂O₃, and SiO₂ contents and the physicochemical proxies such as soil organic carbon (OrgC), total nitrogen (N), and pH of the surface oil in the study area. Then, this study explored the contents and distribution of biological elements Se, F, and I in the study area, as well as their influencing factors. The results are as follows. The soil in the study area is alkaline to strongly alkaline, with average Se, F, and I contents of 0.23×10^-6, 645×10^-6, and 1.06×10^-6, respectively. The average contents of Se and I are lower than their national soil background values, while the average content of F is much higher than its national soil background value. The Se, F, and I contents are positively correlated with each other and all of them are significantly positively correlated with total N. The Se content is negatively correlated with the SiO₂ content, while the I content is positively correlated with the Al₂O₃ content. The contents, distribution, and geochemical characteristics of Se, F, and I are controlled by parent materials and soil types. Among different parent materials, the Se, F, and I contents are higher in the soil of diluvium areas but are the lowest in the soil of alluvium-diluvium areas. Among different types of soil, the contents of the three elements are high in the irrigation-silted soil, while the Se content is the highest and the F and I contents are the lowest in the forest-shrub-grassland soil.

Laochang, Lancang, Yunnan is one of the most important polymetallic mining areas in the southern part of Sanjiang Tethys metallogenic belt. After years of mining, the shallow resources are nearly exhausted. In recent years, granite porphyry and porphyry polymetallic mineralization have been newly discovered in the deep part of the mining area, highlighting the prospecting potential of deep polymetallic deposits. In order to trace the occurrence of deep ore-controlling strata and structures in the study area and help to make a breakthrough in deep ore prospecting, high-power induced polarization method and audio magnetotelluric method were implemented to image the deep structure situated. Results obtained from the inversion of the measured induced polarization and electromagnetic data recuperated the distribution of induced polarization anomalies and the characteristics of deep electrical structure within the study area. Combined with the available regional geological settings, the main conclusions are as follows: The low resistance and high polarization anomalies in the northwest of the survey area are deeply related to the surface ferromanganese, silver manganese, and deep polymetallic mineralization, and the high resistance and high polarization anomalies in the middle and east of the survey area are in good agreement with the deep polymetallic mineralization. The upper Carboniferous limestone and dolomite strata are thick in the west and thin in the east, with the west strata dipping to SW and the east strata overlying the Yiliu Formation of the lower Carboniferous. The concealed granite porphyry dips in NE direction, and the coupling part between its deep 2 300~2 800 m horizontal section and deep fault is a favorable area for deep polymetallic mineralization. Notably, joint interpretation yielded from the high-power induced polarization method and the audio magnetotelluric method applied improved the reliability of deep polymetallic ore detection and provided more information of positioning the subsequent drilling layout.

To achieve the goals of peak carbon dioxide emissions and carbon neutrality, geothermal energy has great prospects for utilization as a type of widely distributed green and clean energy. The tectonic fissure-hosted geothermal water is regarded as an important type of hydrothermal energy for development and utilization because of its high water yield and easy reinjection. This study systematically analyzed the regional structures, formation lithology, water storage space, and water yield property of the urban area of Meixian County in the west of Guanzhong Plain through the regional integrated geophysical exploration, aiming to guide the target area prediction and well placement of geothermal wells. The results show that three concealed faults are present in the target area, of which two faults with favorable water yield property and large scale can be regarded as the faults of the target area. Based on this, geothermal wells were arranged near the fault prediction lines on the hanging wall of the faults, and the weathered zones of the bedrock surfaces were penetrated vertically along the dip angles of the faults. Given the actual geological conditions, such as the faults and the burial depth of the bedrock surface, the geothermal wells had an average drilling depth of 500 m from the bedrock surface. The drilling results show that there are dual-structure thermal reservoirs in the target area, including thermal reservoirs of pore water in the Neogene clastics and those of the bedrock fissure water. Among the eight geothermal wells, seven wells have a water yield of more than 100 m?/h, which mainly originates from the bedrock fissure water, and only one well has a relatively low water yield, which is mainly sourced from the pore water in the Neogene clastics.

The Dashui gold deposit in Maqu County,Gansu Province is a typical mine of the western Qinling region.Owing to continuous mining,many mined-out areas have been formed at different depths below high and steep slopes No.5 and 9,causing local surface collapse and major safety hazards.According to the requirements for environmental protection and safety,there is an urgent need to determine the spatial distribution of concealed collapse to effectively prevent geological disasters.Using the opposing coils transient electromagnetic method (OCTEM),this study conducted the fine-scale interpretation of the anomalies on the typical sections of the exploration area.Based on this,as well as the comprehensive analysis of the hydrogeological data and basic geological data of the exploration area,this study determined the transparent and three-dimensional distribution of the concealed collapse of the Dashui gold deposit.The results of this study show that the subsurface investigation of mined-out areas using the OCTEM can effectively reveal the lithologic and electrical characteristics of concealed strata in mined-out areas.Moreover,the significantly different physical properties between mined-out areas and surrounding rocks can be used to effectively identify the locations and basic morphologies of subsurface mined-out areas.The data on the boundary characteristic points of the mined-out areas on geophysical profiles with multiple exploration lines and three-dimensional modeling allow for the three-dimensional visualization of the spatial morphology of the mined-out areas.The application performance of the OCTEM,along with three-dimensional modeling,provides a technical basis for mine restoration and safety evaluation,thus effectively serving the construction of digital mines.

In recent years,surface karst collapse has frequently occurred in Beihuan New Village,Guigang City,Guangxi,severely threatening the life and property safety of local residents.This study analyzed the distribution of karst in the study area using electrical resistivity tomography (ERT) and delineated zones with strong groundwater runoff,aiming to guide the prevention and control of karst collapse.First,this study conducted numerical simulations to guide the preparation of the field exploration scheme and provide a reference for the analysis of the results measured in the field.Then,it explored the zones with shallow groundwater runoff in Beihuan New Village,delineating 11 zones with potential karst collapse and inferring one major runoff zone and three minor runoff zones.Finally,this study compared the exploration profiles with borehole logs.The comparison and verification results show that ERT has high precision and reliability and can play a significant role in the exploration of urban surface karst collapse.

GOCAD (Geological-Object Computer-Aided Design) is now a piece of internationally recognized mainstream modeling software with functions of powerful 3D modeling, visualization, geological interpretation, and analysis. It has been widely used in the fields such as geological engineering, geophysical prospecting, mining development, and water conservancy engineering. Drilling data and geophysical prospecting data are the important modeling basis for 3D geological modeling. GOCAD provides a general data import function, which, however, is not fully applicable to actual production data. As a result, these data need to be processed and converted before being imported. Based on the GOCAD development kit, this study developed a data interface for drilling data and geophysical prospecting data derived from production to quickly and efficiently import multi-source geological prospecting data into GOCAD, thus greatly saving the time for 3D geological modeling.

The Xiangshan ore field is the largest volcanogenic uranium ore field in China with abundant uranium resources and favorable geothermal geological conditions. However, few studies have been conducted on its thermal structure and mineralization characteristics,In order to solve this problem effectively. Taking the Zoujiashan super-large uranium deposit in the west of the ore field as a typical area, this study systematically investigated the thermal structure characteristics of the ore field, established the thermal structure model, and analyzed the relationships between heat generation and mineralization. The results are as follows. The thermal structure in the study area is of the hot-mantle and cold-crust type, which is in line with the characteristics of thermal structures in eastern China. The higher crustal heat flow in the area is closely related to the uranium source and uranium ore bodies, and the decay heat generation of radionuclides is the main source of the crustal heat flow. The thermal anomalies in the area are obviously controlled by faults, and the heat source is highly consistent with the uranium source. The geothermal gradient anomalies are one of the prospecting criteria of the area. Moreover, 4 ℃/100 m is the positioning marker of deposits, and the variation amplitude of geothermal gradients can be used as the positioning marker of rich and large ore bodies. This study provides effective technical support for the study of geothermal geology and metallogenic geology in this area.

The Daguanchang uranium deposit, a typical concealed volcanic hydrothermal uranium deposit, was selected to investigate the relationship between surface geochemical characteristics and deep uranium ore bodies of volcanic hydrothermal uranium deposits in North China. The samples for soil survey were collected in the Daguanchang mining area. They were taken from the soil in the upper part of boreholes revealing deposits and mineralization for the analyses of the instantaneous radon (Rn) concentration, mobile-state uranium, and ²¹⁰Po of soil. Then, this study explored the relationships between these geochemical characteristics and deep uranium ore bodies. The results are as follows. The soil in the upper part of boreholes revealing high-grade deposits (also referred to as high-grade boreholes) had significantly higher instantaneous Rn concentration than that in the upper part of boreholes revealing mineralization (also referred to as mineralization boreholes). The high instantaneous Rn concentration in the soil samples collected from a large area corresponded well to the deep uranium ore bodies. The high-grade boreholes had slightly high ²¹⁰Po. However, the ²¹⁰Po in the surface soil samples showed small dispersion and relatively uniform distribution and did not exhibit differences between the barren and mining areas. Mobile-state uranium in high-grade boreholes did not exhibit significant anomalies. The maximum anomaly value of mobile-state uranium in soil samples collected from a large area occurred in the known barren areas. Therefore, it can be preliminarily concluded that, for the exploration of deeply buried uranium ore bodies on a large scale, the anomalies of instantaneous Rn concentration in the soil can indicate the anomalies of deeply buried uranium ore bodies, while the mobile-state uranium and ²¹⁰Po in soil are less sensitive than instantaneous Rn.

Based on the characteristics of the physical geography,topography,and hydroclimatology of Morocco and years of experience in the geochemical survey in Morocco, this study divided the geochemical landscapes in Morocco and plotted the geochemical landscape zoning map of Morocco. As a result, Morocco was divided into six first-order geochemical landscape areas, namely a forest coverage area, a semi-arid high mountain area, a humid-semi-humid middle-low mountain and hill area, an arid-semi-arid middle-low mountain and hill area, an arid desert and gobi area, and a desert coverage area. According to the elevation and surface cutting intensity, the humid-semi-humid and arid-semi-arid middle-low mountain and hill areas were subdivided into four second-level landscape areas each, namely a hill area, a low mountain area,a shallow-cutting middle mountain area,and a medium-deep-cutting middle-mountain area. Based on this division scheme, this study proposed several suggestions for geochemical surveys in Morocco.

Focusing on the spring and lake water in the Hongshan Lake in the Tianshuihai area, Xinjiang, China, this study explored the formation process of the hydrochemical components in the water and the geochemical characteristics and sources of the water bodies through hydrogeochemical testing and analyses. Accordingly, the hydrocarbon-related hydrogeochemical information was obtained. The results are as follows: The spring water in the Hongshan Lake is weakly alkaline in general and dominated by brackish water. The mass concentration of main ions in the water bodies increases with increasing salinity. The water has a hydrochemical type of Na-HCO₃ and is mainly charged by atmospheric precipitation, which interacts with the surrounding rocks during the deep circulation along faults or fractures. The salinity, hydrochemical type, and characteristic coefficient of spring water indicate that the groundwater in this area features weak hydrodynamic force and deep metamorphic degree, which are similar to the characteristics of the formation water associated with hydrocarbon in oil fields. Therefore, it can be inferred that the geological environment in this area is conducive to the generation and preservation of hydrocarbon resources.

The Dongjianian silver deposit, located on the southern margin of the Xiaoqinling Mountains, is controlled by the secondary structures of the Xiaohe fault and is the first large precious metal deposit discovered in the southern belt of the Xiaoqinling Mountains. This deposit has three hydrothermal metallogenic stages, namely the quartz-pyrite metallogenic stage (Ⅰ), the dominant quartz-polymetallic sulfide metallogenic stage (Ⅱ), and the quartz-carbonate metallogenic stage (Ⅲ). Three types of inclusions have primarily developed in the ore bodies, namely gas-liquid two-phase inclusions (W-type), CO₂-bearing inclusions (C-type), and pure CO₂ inclusions (PC-type). Stage I primarily witnessed the development of C- and W-type inclusions and a small quantity of PC-type inclusions, and stage II mainly saw the development of W-type inclusions and a small amount of C-type inclusions. The quartz fluid inclusions formed in stages I and II have homogenization temperature ranges of 151~270 ℃ and 126~240 ℃, respectively, which exhibits a downward trend. Their salinity varies slightly in the ranges of 3.8%~22.42% NaCleqv and 4.16%~20.48% NaCleqv, respectively, indicating a low-salinity environment. Their CO₂ content transformed from enrichment into deficiency. The metallogenic pressure and depth were estimated to be 22.08~76.6 MPa and 3.77~7.13 km, respectively. Therefore, the Dongjianian silver deposit is a low-salinity medium- to low-temperature meso-epithermal silver deposit.

Poor illumination poses great challenges to the imaging of small-scale faults and pores.Subsurface attenuation leads to amplitude loss and phase distortion of seismic waves,and ignoring such attenuation during imaging will blur migration amplitudes.The Q-compensated least-squares reverse time migration (QLSRTM) can improve the imaging of these small-scale structures,but it requires a huge amount of iterations and computational cost.To improve the imaging effect of these small-scale structures,this study proposed a geological-target-oriented joint QLSRTM (J-QLSRTM) that fully utilizes diffracted waves.In this method,a new objective function and gradient formula was constructed.Moreover,the Q-compensated wavefield propagation operators,Q-compensated adjoint operators,and Q-attenuated demigration operators were derived for both primary and diffracted waves based on the inversion and adjoint theories.The numerical examples verified that the proposed J-QLSRTM is superior to the conventional QLSRTM and the acoustic J-LSRTM.

Southern Sichuan Province has widely developed karsts and densely distributed coal mine goafs, which cannot be accurately detected and identified using a single existent exploration method. Consequently, large-scale and industrial drilling for shale gas is prone to induce failures and complex events. In light of the complex topographic and geological conditions in southern Sichuan, this study conducted tests and comparative analysis using multiple engineering geophysical exploration methods including electrical resistivity imaging, shallow seismic method, transient electromagnetic method, audio-magnetotelluric method, and microtremor survey method. As a result, an integrated engineering geophysical exploration technology for shale gas well platforms in southern Sichuan was formed and applied to the construction of shale gas well platforms. As indicated by drilling results, the integrated technology can effectively identify unfavorable geological bodies (e.g., shallow karsts, coal mine goafs, and overburdens) at a depth of less than 1000 m and provide technical support for siting shale gas well platforms, optimizing casing programs, predicting drilling risks, shortening drilling cycles, and protecting ecological environment, with remarkable economic, social, and ecological benefits having been achieved. Moreover, this integrated technology provides a technical guarantee for the construction of both the Changning-Weiyuan national shale gas demonstration zone and the southern Sichuan shale gas exploration and development pilot zone and accelerates the shale gas development in southern Sichuan.

The Matou gold deposit is located in the Mianning-Yanyuan strike-slip orogenic belt and is part of the deeply cut Quaternary coverage area and, thus, has limited surface prospecting clues. In this prospecting stage, a comprehensive anomaly area was delineated through the 1:10 000 soil geochemical survey. Then, gold ore bodies were discovered through trenching engineering, indicating excellent prospecting performance. Moreover, this study established a geological-geochemical prospecting model dominated by the HT³ anomaly area by combining the geological and geochemical anomalies in the work area. Finally, the next prospecting direction was proposed.

The inversion of electromagnetic detection data is a typical ill-posed problem and is prone to cause a multiplicity of solutions of the inversion results. The ill-posedness is an inherent characteristic of inversion and is difficult to overcome without additional information. An effective way to solve this problem is constrained inversion. In this study, the Gauss-Newton - conjugate gradient (GN-CG) method was used to directly impose constraints on the inversion objective function. Specifically, the dielectric resistivity range was introduced into the inversion objective function as the prior information and constraints using the exterior penalty function method. Compared with the conventional three-dimensional resistivity inversion objective function, the objective function with inequality constraints can suppress the multiplicity of solutions in theory. As revealed by the testing results of various theoretical models, the three-dimensional borehole-to-surface resistivity inversion algorithm based on inequality constraints effectively improves the precision of inversion results, and the way of imposing inequality constraints using the penalty function method is feasible and effective.

Geothermal energy mainly migrates and accumulates along fractured zones. Ascertaining the faults in the study area is an important goal of geothermal exploration. Many faults are distributed in the Zhangye-Minle basin. They are deeply buried and are difficult to find on the surface. The special geological conditions make it difficult to fully utilize the advantages of conventional geophysical methods. By contrast, the activated charcoal radon measurement features strong anti-interference, large detection depth, and low cost, which are unique advantages in detecting concealed structures. This study investigated the concealed structures in the Zhangye-Minle basin using the activated charcoal radon measurement. Through the trend analysis of measured radon concentrations, this study extracted local anomalies and determined the favorable parts for the geothermal water exploration in the study area, creating conditions for further drilling and shallow artificial seismic exploration.

As resource exploration deepens and becomes increasingly difficult,improving the imaging precision and the reservoir prediction accuracy under a complex tectonic setting has become a top priority of research.The full waveform inversion (FWI) method developed in recent years can be applied to complex geological structures.This method can reveal structural details in a complex geological setting using the dynamic and kinematic information in the pre-stack seismic wave field.However,this method involves many research elements such as model parameterization,building of inverse error function,data preprocessing,numerical simulation of wavelengths,and wavelet estimation.Thus,its development is bound to be a long-term gradual improvement process.The FWI method has been applied to actual observation data with the development of theory and computer technology.This study introduced the principle and processing flow of the FWI method and summarized its development history and its application status in marine and onshore seismic data,and deep seismic reflection data.Accordingly, this study presented the current application bottlenecks,data processing difficulties, and challenges of deep-crustal inversion imaging for subsequent research and application of the FWI method.

Upward continuation is one of the important methods used to separate gravity anomalies. However, how to quantitatively select an appropriate upward-continuation height has always been a problem in the application of this method. Given this, this paper proposes a curvature analysis method based on the least square method to quantitatively determine a reasonable upward-continuation height. The steps of this method are as follows. Perform upward continuation to different adjacent heights for observation data, and then use the least square method to estimate the least square error of the upward continued value of adjacent heights.There is a maximum curvature in the least square curve of upward-continued values of all adjacent heights.At the point of the maximum curvature, the local anomalies are attenuated to the greatest extent, while the regional anomalies are preserved as far as possible. Therefore, this point can be approximately regarded as the optimal upward-continuation height. As indicated by tests using the data of a theoretical model, the method proposed in this paper can be used to qualitatively determine a suitable upward-continuation height, thus providing an important reference for the selection of upward-continuation height in practical applications.

This study designed a group of 2D peak-valley comprehensive terrain models with different widths and slopes and investigated the influence of differently undulating terrains in mountainous areas on the audiomagnetotelluric (AMT) data and corresponding distortion characteristics from seven aspects, namely polarization modes, frequency, positions of measurement points, the width of a mountain top, the elevation difference and slope of terrain, and phase curves. The results are as follows. The transverse magnetic mode (TM mode) is more susceptible to terrain than the transverse electric mode (TE mode). The undulating terrain has little influence on the high-frequency parts of AMT data but has a great influence on their low-frequency parts. The apparent resistivity and phase of different frequency points at a measurement point reflect the comprehensive influence of all terrains within the skin depth level rather than just the influence of a single mountain peak or valley near the measurement point. Measurement points located at the mountain peaks are more easily affected by terrains than those in the valleys. Moreover, narrower mountain tops correspond to greater elevation differences of terrain, and steeper terrain exerts greater influence. In addition, the comparison of the 2D_TE results of the inversion considering and not considering terrains show that the 2D inversion considering terrains can effectively eliminate the influence of terrain. The 2D inversion considering terrains was carried out for measured AMT data. As indicated by the inversion results, the 2D inversion considering terrains can effectively eliminate the false high and low resistance anomalies and relieve the "hanging surface" phenomenon of signals, and the results corresponded well with the horizons with encountered manganese of three boreholes.

The seismic impedance inversion is nonlinear optimization based on seismic data to obtain wave impedance parameters.The global optimization algorithm independent of the gradient information of objective function is an effective method for seismic impedance inversion.However,this method adopts a trace-by-trace inversion strategy and ignores the spatial correlation of adjacent seismic traces,resulting in poor lateral continuity of the inversion results.Given this,this study proposed a model space initialization method integrating the optimal solution of the bypass to restrict the search space of wave impedance inversion,in order to improve the lateral continuity of inversion results.Based on this,this study proposed a seismic impedance inversion method with lateral constraints based on multi-group variation differential evolution.A case of synthetic seismogram shows that this method has a higher convergence rate and better lateral continuity of inversion results than conventional methods.This method was applied to the inversion of reservoir impedance parameters of a block of the Shengli Oilfield.The obtained inversion results were in good agreement with the logging data and effectively characterize the thickness of reservoir sandstone.

The seismic slope tomography is an effective method for building macro-velocity models using the travel time and slopes of locally coherent events of reflected waves.For data with low signal-to-noise ratios,the deep effective reflection wave data that can be picked are often far fewer than the shallow reflection wave data,resulting in a poor tomographic inversion effect of the velocity of the deep strata.Therefore,this study proposed a 3D seismic slope tomography method based on depth weighting.In the linear tomographic inversion equation of each iteration,the depth weighting was performed for the kernel function of the observed data on the node velocity of the discrete model.The weighting coefficient was determined according to the node depth of the discrete model and the reflection point depth of each shot-detection pair of the current iteration,increasing the constraining effect of deep reflection wave data on the deep velocity.Meanwhile,the shallow velocity was mainly constrained by the shallow reflection wave data.As a result,the inversion effect of deep velocity could be improved while maintaining the inversion precision of shallow velocity.The application and tests of both theoretical model data and actual data yielded satisfactory results,verifying the effectiveness of the method.

This study aims to further understand different input ways of heavy metal elements into the agroecosystem and resultant soil pollution and to promote the sustainable development of agriculture in the Jianghan Plain. To this end, data were collected from the geochemical assessment project on the land quality of Honghu City from 2014 to 2019 and were studied as a whole. Then, this study conducted geochemical analyses of heavy metal elements such as Cr and Hg input via three ways, namely atmospheric dry and wet subsidence, irrigation water, and chemical fertilizers, and calculated the input amount of the heavy metal elements via each way. Based on these, this study explored the impacts of the three ways on land quality. The results are as follows:①The land quality in Honghu City is slightly affected by human activities; ②The total input flux of different elements differs greatly with the input ways, reflecting the differences in the heavy metal elements input via local agricultural activities; ③The annual input flux of heavy metal elements via irrigation water is relatively high, and irrigation water contributes the most to the heavy metal elements (except for Zn, Cr, and Pb) input to soil.

Glacial landforms, such as cirques, razorback ridges, horn peaks, and alpine lakes, are commonly developed in the surrounding areas of the Tangbu section of Dongcuoqu in the Nujiang River Basin in southeastern Tibet, indicating that intensive glacial activities once occurred in this area. However, field surveys show that proluvium and alluvial-diluvial deposits are mainly distributed in the Quaternary surface of this section. The comprehensive analysis of the audio-frequency magnetotellurics and high-density measurement results of this area show that the electrical characteristics of the Quaternary in this section are highly consistent with the moraine deposit structure. Combined with the commonly developed glacial landforms in the surrounding area, it can be inferred that the Quaternary stratum in this section is mainly dominated by moraine deposits, which are covered with a layer of proluvium and alluvial-diluvial deposits. From the perspective of the electrical structure characteristics of the geophysical exploration results, the resistivity results of the audio-frequency magnetotellurics can effectively reflect the structural characteristics including the thickness of the moraine deposits, glacial valleys on the bedrock surface, and moraine lenses, and the resistivity results from high-density measurement can well reflect the characteristics of moraine melange, moraine lenses, and the long axis direction of large boulders.

Magmatic rock areas suffer poor water yield property and lack groundwater overall, encounter great difficulties with water exploration, and generally face the problem that available water resources fail to meet the demand. Targeting different types of water exploration targets and combining the geological and physical property characteristics, hydrogeological conditions, and field survey of the exploration target areas, this study comprehensively analyzed the electric structure characteristics, well completion modes, and water yield mechanisms of the strata around Xiaoshuicha and Wawu villages in Laiyang City through interpretation and analysis using comprehensive geophysical exploration method consisting of apparent resistivity profiles and apparent resistivity-based vertical sounding. After determining water exploration targets, conducting interpretation and analysis of geophysical prospecting, and locating wells through comprehensive analysis, this study successfully drilled two wells in the two villages, obtaining maximum water yield of 247.56 m³/d and 620.64 m³/d each. Finally, this study analyzed the water yield mechanisms in detail based on the intrusion-contact zone types and water-storage structural models with dykes conducting water. This study not only solves the difficulty with water use of local people but also provides a certain reference for future water exploration and well locating in similar areas.

Based on the statistical analysis of the Se distribution in 8,835 soil samples and 240 sets of crop-root soil samples, as well as related survey data in the Shizuishan area of Ningxia, this study summarized the element geochemical characteristics of the local Se-rich soil and explored the development and utilization prospects of the soil and related issues. The study results are as follows. ① The newly delineated Se-rich land (soil with Se content of ≥0.222×10^-6; local standard of Ningxia) covers a total area of more than 1,000 km², including more than 25% of Se-rich farmland, and the effective Se content is mostly over 10% of Se in the soil; ② The Se-rich soil has pH of greater than 7.5 and organic matter content of less than 10.26%, without heavy metal pollution. There are significant positive correlations between the Se content and the contents of organic matter, B, Mn, Mo, Cu, and Zn and a negative correlation between the Se content and pH; ③ The correlation coefficient between effective Se and Se in the soil is r = 0.39, and those between effective Se and OM, CEC, and N are 0.33 to 0.5; ④ Among the 10 types of Se-rich agricultural products (i.e., Se-rich wheat) obtained in Se-enrich soil through spot check, the wheat has been proven to have the strongest capacity to absorb Se, with an average bioconcentration coefficient of 0.12; ⑤ Since the unique Se-rich soil resources in this area is of great value in development and utilization, it is necessary to strengthen the R&D of characteristic Se-rich crops (i.e., wheat, rice, wolfberry, and grape) and the development of relevant Se-rich standards through scientific research and reasonable planning.

Echoes can be distorted due to the temperature drift of the ground penetrating radar (GPR) system,the low-pass effect of lossy media,and the decline in the coupling between the antenna and the ground.The mixing of effective radar echoes and zero-offset components makes it difficult to detect weak signals.The conventional front-end correction and post-processing methods,which aim to improve the transmission efficiency and remove the clutter noise,fail to improve the signal-to-noise ratio (SNR) and sensitivity of the system.To overcome these obstacles,this study improved the equivalent sampling circuit using a real-time correction method based on time-varying zero offset.Specifically,the zero-offset coefficient of each sampling was controlled separately and was updated in real time on each sampling.No DC and low-frequency components were sent into the subsequent programmable amplifier along with effective signals,ensuring the correct acquisition of weak signals and the dynamic range of the system.Experiments have proved the validity and feasibility of this method,which has been applied to a new type of digital GPR product.

The Technical Symbols for Geochemical Exploration (GB/T 14839-93) is a national standard formulated in the early 1990s, including 101 symbols. The revision of this standard began in 2019 according to the following principles: (a) Inheriting the original symbols. The stability and continuity of the original standard content should be maintained as far as possible; (b) Selecting new symbols in line with professional habits. It is necessary to select symbols that are widely used in geochemical exploration and are recognized by most peers as far as possible; (c) Matching the development of geochemical exploration technologies. The revised technical symbols for geochemical exploration should cover all fields involved in the current geochemical explorations; (d) Focusing on the commonly used geochemical symbols. The commonly used geochemical symbols should be included. According to the above principles, special technical symbols for ecological geochemical surveys and evaluation were newly added, and the expanded symbols include general technical symbols for geochemical exploration and special technical symbols for mineral geochemical exploration and geochemical sample testing. A total of 173 symbols were included in the revised standard. The revised technical symbols for geochemical exploration can be divided into a general type and a special type according to their application scopes. The special geochemical symbols can be categorized into three subtypes according to their application fields, namely mineral exploration, ecological environment investigation and evaluation, and geochemical sample testing. The fields covered by the revised standard are consistent with the current application fields of geochemical exploration technologies.

The Western Dinosaur Park of the Lanzhou New area, located in the Lanzhou-Minhe Basin, has encouraging prospects for geothermal exploration, development, and utilization. Based on the previous results of regional geological structure and geothermal characteristics, this study further investigated the geothermal reservoir horizons and the geothermal geological conditions using both the controlled source audio-frequency magnetotellurics (CSAMT) and the magnetotelluric sounding. Then, available geothermal water with suitable temperatures was discovered by drilling. Based on the geophysical exploration and drilling results, this study deduced and explained the structure and pluton distribution of the study area, analyzed the geothermal geological conditions, and pointed out the future exploration direction. The results of this study can be utilized as a reference for geothermal exploration in adjacent areas of the Western Dinosaur Park and similar areas.

The area around Maduqiao Village, Langqiao Town, Jing County has great potential for the development of high-quality mineral water. However, due to the geological conditions and the inhomogeneity of water-bearing media, the investigation of the distribution range of the mineral water in the area and the quantitative evaluation of the water quantity and quality have always been challenges to the development and utilization of mineral water in the area. With the Langqiao area of Jing County as the target area, an application study on the comprehensive geophysical prospecting method that comprehensive ground geophysical prospecting with hydrogeological logs was conducted, achieving important progress. The major results are as follows: (1) The fault structures in granodiorites were precisely located through comprehensive ground geophysical prospecting, and the horizon of tectonic fissure water was precisely identified based on hydrogeological logs; (2) The metasilicate natural mineral water for drinking with a single well water yield of 50~80 m³/d was identified; (3) The water-rich fault structures in the study area have a medium to shallow burial depths of about 75~140 m and primarily have a NW strike. These results reveal the spatial distribution characteristics of the mineral water-bearing structures in the study area and are of great significance to the subsequent investigation of the mineral water range. Moreover, the systematic research philosophy and technical methods used for the Langqiao area of Jing County in this study can guide the mineral water exploration in similar areas.

To achieve the accurate positioning of the water-conducting channels in the areas with unknown anomalous water inrush in the Beiminghe iron mine to ensure the safe production of the mine, this study explored the 11# across-vein roof at -110 m level in this iron mine using the mine transient electromagnetic method (MTEM). Firstly, this study briefly introduced the basic principle of MTEM and theoretically analyzed the characteristics of mine transient electromagnetic response under metal interferences. Then, it analyzed the geophysical characteristics based on the geology of the iron mine and corrected the measured data targeting metal interferences using the coefficient correction method. Afterward, the measured data were used as the initial model for the inversion of full-space transient electromagnetic using the bee colony algorithm, obtaining the high-resolution resistivity images of the working face roof. The images combined with the existing geological data allow for the fine detection of water-rich anomalous areas and water-conducting channels, and the detection results were verified by drilling. The results show that the MTEM can effectively improve the detection accuracy of water-rich anomalous positions in the roof strata of the working face in iron mines by means of effective data processing, thus providing effective technical support for water control in iron mines.