The mineralization sequence of regional geochemical elements lies in the statistic analysis of such parameters of element analytical data from regional geochemical samples as variation coefficients, sample number, deviations, concentration coefficients and minimum concentration coefficients by means of mathematical statistics to obtain the mineralization coefficients in the form of formula quantification, thus determining regional geochemical mineralization sequence. Based on the determination of the mineralization sequence, the author has found that W, Au, Bi, Sn, Pb, F, Ag and Cd constitute the major ore-forming elements (indicator elements) in the eastern segment of Qimantag area, that the Xiaomiao rock formation of Changcheng System and the Indosinian intrusive rocks are major ore-prospecting target areas, that the contact zones between the Indosinian intrusive rocks and carbonate rock-bearing strata of Jixian System, Baishahe Formation, and Carboniferous-Permian rocks are major ore-forming districts of Cu, Pb, Zn, Fe polymetallic ore resources, that Au metallogenic areas are mainly distributed in strata of Qimantag Group in central and western parts of the study area, and that the mineralization should belong to the shattered alteration rock type related to Baiganhu fault and its secondary faults. Based on regional ore-forming geological conditions and geochemical composite anomalies, the authors indicate the ore-prospecting target areas of the major ore-forming elements.

The Pala area is the most important mining area for alluvial gold in Mayo Kebbi Region, Chad. Many companies tried to find rock gold in this area; nevertheless, they all failed to find any good ore bodies in spite of lots of trenching and drilling work. To illustrate the formation process and origin of gold anomalies, the authors conducted geochemical exploration of gold mines in Pala with the purpose of summing up the characteristics of secondary halos of Au in African tropical grassland landscape. Vertical soil profile measurement was also made to analyze the geochemical behavior of Au during pediplanation so as to explain the origin of gold anomalies. The results obtained by the authors are of directive significance for gold exploration work of China's companies in Africa under the same landscape condition.

The Shawan fault zone in the Pearl River delta consists of a group of NW-striking faults, discontinuously exposed and concealed. In the detection of this group of faults, the authors adopted the integrated geophysical-geochemical method comprising geophysical survey, shallow seismic reflection method and high-density electrical method as well as geochemical survey. Integrated survey was conducted for 4 concealed faults (Dawugang fault, Shawan fault, Chencun fault and Zini fault) which belong to the Shawan fault zone. During the detection, 7 anomalies were delineated, and geometrical information concerning the fault position was preliminarily obtained, thus laying the foundation for drilling verification.

Forest swamp is an important landscape type in China. New technology has been used to re-implement the regional geochemical survey of the forest swamp landscape since 2000. An area of 290 000 km² had been completed by the end of 2011. 73 000 pieces of stream sediment samples were collected and analyzed for 39 elements or oxides. Valuable geochemical information was accumulated in this study. Series of geochemical parameters such as the average, median, standard deviation, and range of elements content were calculated by JinWei software of geoscience information processing application systems (GeoIPAS). The results provide some important reference information concerning the regional geochemical characteristics of the landscape area and geochemical anomalies for further evaluation of mineral resources in such landscape areas of China.

In the utilization of geophysical methods to detect underground water in karst mountain areas of Southwest China and the determination of suitable well position, the correct analysis and judgment of the properties of anomaly source and the choice of proper methods constitute the key to the successful exploration of underground water. Based on an analysis of the cases of successful water exploration in quite a few karst mountain areas in Long'an County of Guangxi, the authors put forward the geophysical water exploration model based on the combination of audio frequency telluric electric field method and audio frequency magnetotelluric sounding method, and made a tentative analysis of its exploration effect. Some experience concerning the determination of suitable well position was summed up as reference for water exploration workers in this region.

In western Sichuan basin depression, the marine facies target layers are buried in great depth, resulting in narrow frequency band of reflected seismic data. Hence seiemic resolution can not meet the need of prospecting goals, and low seismic resolution is responsible for stratigraphic absorption attenuation. In order to understand completely the reason for the attenuation of seismic waves, the authors built a model for western Sichuan basin depression strata, then calculated quantitatively spherical divergence, absorption and transmission attenuation of seismic wave based on the model, and combined the calculated attenuation values with seismic data, VSP and Walkway-VSP data to analyze the factors affecting high frequency reflected signal acquisition recording of deep layers. It turns out that the serious absorption attenuation of shallow strata above 1500 meters is the fundamental cause responsible for high frequency component losses of deep layers in western Sichuan basin depression and, as for the marine facies target layers buried deeper than 5000 meters, field acquisition data can only reach about 40Hz frequency band. Therefore, the field acquisition methods aiming at deep target layers should focus on reducing background noises and increasing acquisition density to enhance weak reflection signals of deep layers so as to improve the seismic prospecting precision, rather than solely focus on improving the seismic resolution.

The Yingqiong basin possesses abundant natural gas resources; nevertheless, except for a few large gas fields which have already been put into production, the exploration extent there is rather low. As the drill holes are insufficient in this basin it's very difficult to understand the longitudinal and horizontal variation trends of the velocity. Besides, the work of velocity calibration often encounters remarkable errors, which causes difficulty in drill hole employment. There exist mainly two difficult problems: one is the existence of considerable error between the predicted depth and the drilling depth when the time-depth relationship of the surrounding drilled well is adopted; the other is the existence of rather large deviation between the VSP calibration velocity of DFIPO well in Dongfang diapiric area of the Yingqiong basin and the regional velocity. Aimed at solving these two difficult problems, the authors conducted methodological study and put forward effective train of thought and means, thus improving the accuracy of velocity prediction in the study area.

The study of the geochemical characteristics of Beishan area in Weining of Ningxia was based on the 1:50 000 stream sediment survey. This paper highlighted elemental distribution characteristics, multi-elementary anomaly characteristics, element correlation and element anomaly assemblages. The results show that Au, Ag and Cu possess large anomaly area, a good parallelism with the fault and great relative dispersion extent, suggesting a huge metallogenic potential in the study area. Four prospective areas were delineated. Jinchangzi-Duicaogou area, Tuyao area, Datonggou-Zhaobishan area and Shaoniukouzi area are expected to be promising areas for Au-Ag-Cu-Pb-Co deposits, Au-Ag-Cu-Co deposits, Ag-Cu-Co deposits and Au-Ag deposits respectively.

With the high-precision magnetic survey data obtained from the Xiayu iron deposit as the basis, the author adopted the wavelet multi-scale analytical method to decompose the magnetic anomaly into space of different scales and, in combination with spectrum analysis method, effectively obtained field source anomaly characteristics at different depths of the Xiayu iron ore deposit, thus improving the interpretation precision of the magnetic anomaly. It is inferred that there exists no iron ore body below 200 m in the Xiayu iron deposit. The geological body model established on the basis of geological data available were utilized to display the shape of the ore body through two-degree-and-a-half interactive inverse fitting, and the depth of the corresponding anomaly body was analyzed. The results obtained further prove the accuracy of the wavelet multi-scale decomposition method in judging the distribution of the ore body from another angle.

Borehole induced polarization method (referred to as borehole IP) is the general term of induced polarization measurements in the borehole. This paper describes the basic principles of the prospecting for blind ore bodies beside and at the bottom of the borehole as well as the application examples using IP/resistivity methods for the surface-to-borehole work pattern. The basic principles of detecting deep blind deposits, the delineation of the ore bodies and the application examples using IP/resistivity method for the borehole-to-surface work pattern are dealt with, and the examples of detecting ore bodies between boreholes are presented. The effect of borehole induced polarization / resistivity method in the exploration of mineral resources is systematically reviewed.

Tailing samples were collected by drilling in No. 1 tailing dam from the Dexing mine. The multi-element analytical scheme were applied. The tailing size was determined by the laser grain size analytical instrument, and the mineral form was determined by X-ray powder diffractometry. Some conclusions have been reached: The major particles of the tailing are silty, with quartz and sericite as the main minerals, while the content of metal minerals is less than 1%. The water-sorting action and supergene geochemical process in the tailing dam combined with changes in ore grade and mineral processing caused uneven distribution of elements and particle sizes of tailing. The tailing particle size decreases in the direction of the tailing discharge, and the elements can be divided into 3 zones: Cu, Fe, Mo→SiO₂, Au→Al₂O₃, Tl. During the supergene geochemical process, the sulfide was weathered into oxides,which led to the significant decrease of the pyrite content, with the loss of Cu, Mo, S, Fe, Ca and C in tailing. Meanwhile sericite changed into illite.

Since the paper published in The Leading Edge (No. 1 issue of 2006 ) described in detail the theory, equipments and outdoor test results of magnetic gradient tensor, this technology has become one of the hot topics of magnetic prospecting methods. This paper describes the concepts and advantages of the magnetic gradient tensor. Both frequency and spatial domain methods are used to transfer borehole three-component magnetic data to magnetic gradient tensor. According to the joint inversion principle and Euler deconvolution, the joint inversion equations for magnetic gradient tensor are deduced, which enable us to flexibly inverse one or more components based on a weighted function matrix, and the technology is more common than the method mentioned in Reference [14]. The simulated results of synthetic models reveal that the magnetic gradient tensor inversion method can be accurately employed to locate the magnetic body according to borehole bottom anomalies. Concerning 3D models, only one borehole magnetic data can calculate the locations accurately. Moreover, the method was applied to interpreting the three-component magnetic data of No.18-2 drill in Daye iron mining area, Hubei province, and the results indicate that the deconvolution solutions of magnetic gradient tensor are concentrated on the 100 to 180 m and 500 to 550 m elevations that are in accordance with the drilling results. The result confirms the geological inference that there are two steps of iron ore bodies, which has practical significance in search for ore bodies at deeper locations in Daye iron mining area.

For the purpose of proper utilization of aero geophysical survey method in the Tibetan Plateau, which is characterized by high altitude, large scale and low flying height, the authors selected a suitable type of helicopter, and carried out some tentative ground and air researches on the selected helicopter's magnetic interferences form, frequency, amplitude, attenuation regularity and, on such a basis, designed a long firm anti-vibration survey system suitable for AS350-B3 helicopter. The experimental results indicate that magnetic interference in a geophysical aircraft environment comes from several sources, which include 700 nT/96 s pulse and 300 nT/s square wave magnetic interference as well as 20 nT/s from rate of change of movement of conductive surfaces with rotary wing. Through low flying height and high quality data survey in central and south Qilian of Qinghai Province, the authors prove that AS350-B3 helicopter and a long firm anti-vibration survey system can be used for a large scale, low flying height aero geophysical survey in the Tibetan Plateau.

This paper proposes a method to compute the DWT (discrete wavelet transform) coefficients using Mallat's fast algorithm with Daubechies N (N=1,…,10) wavelet series as the wavelet primary function. The authors verified the reliability of the method with a theoretical model. By using an approach to multi-layer decomposition and a strategy of threshold value in the process of the airborne gravity data denoising, the authors extracted the free air gravity anomalies by the frequency and bandwidth character of the gravity anomalies. A comparison is made by using six, seven and eight layers decomposition and by employing the soft-threshold and the hard-threshold denoising. The results demonstrate that the free air gravity anomalies extracted by this method are quite consistent with the filtered results of the GT-1A system.

Through the analysis of tilt angle concept, this paper puts forward a method for normalized vertical derivative using the characteristics of Inverse Hyperbolic Tangent function, with the purpose of detecting geological boundaries in potential field and extracting geological body distribution, characteristics of fracture structure and other geological information. Theoretical models and practical data processing show that the method can be an effective method for detecting geological boundaries with higher resolution and obtaining abundant geological information and is also of certain significance for detecting the geological boundaries, dividing tectonic units, and determining the fracture zone and the trend of geologic structure.

It is usually necessary to consider the magnetization direction of the magnetic body in the interpretation of three-component borehole magnetic data; however, it is rather difficult to determine the magnetization direction under the strong effect of remnant magnetization or demagnetization. The modulus of magnetic anomaly is not dependent or insignificantly dependent on the magnetization direction, and modulus can be calculated directly by using three-component borehole magnetic data. The authors hence tried to inverse the model parameters with the modulus of three-component borehole magnetic data. First, the value of the modulus was calculated by using three-component borehole magnetic data. Then, the geometrical and magnetic parameters of 2D tabular body and vertical cube were inversed with the modulus data. Finally, this method was applied to the borehole magnetic data of an iron ore mine in Xinjiang. The results show that the modulus inversion result is less influenced by magnetization direction when magnetization direction is unknown or inaccurate; the modulus inversion is superior to the traditional inversion using single-component Za and receives good geological results.

In this paper, mercury vapor survey was employed to detect or judge the location and the grave robbery situation of the Spring-Autumn Tomb in Hancheng City. In the burial ground and peripheral section, a variety of methods of mercury vapor survey were carried out for mercury in air, mercury in soil gas and thermal-release mercury of soil in different parts of the grave. The high concentration mercury anomalies were delineated. This paper demonstrates that the shape and area of the distribution of mercury anomalies delineated by mercury vapor survey can be used to find the location of the tomb and the place of the cave dug by tomb-robbers.

The complicated piedmont belt is the main field for oil and gas exploration in new exploration regions of West China. The particular surface geological conditions and complicated deep geological structures of these regions cause outstanding problems such as static correction, complex seismic wave field and low SNR seismic data. Aimed at solving these difficulties, this paper puts forward the design of seismic geometry in western piedmont belt, which is based on the comprehensive real surface model with pre-stack imaging effect in combination with the design technology for the observation system of CRP analysis technology. This technology was used in Hashan 3D block for optimization design of the observation system, with fairly good results obtained.

The audio magnetotelluric sounding method (AMT) is widely used in the highway and railway tunnel exploration to prevent geohazards during the drilling process. Most of the recent survey results show that this method has the capability of locating faults and shatter belts for which the engineering geological survey shows much concern. However, the abnormity is in low resolution and it is very difficult to determine characteristics of the dip of the fault or even to detect whether the fault is normal or reverse. The authors designed two typical comparable fault models for modeling the AMT data and used the synthetic data to do 1D and 2D inversion. A detailed comparison demonstrates that TM data show good results for characteristics of the layer while TE data give more information concerning the target orientation. The research mode used in this paper has certain reference significance for this kind of applications under complicated geological and geophysical conditions.

This paper introduces the technical measures of the CSAMT in the detection of urban faults in the aspects of data acquisition, data processing and methods of overcoming the electromagnetic interference, on the basis of geological data available. There are multiple buried faults in the new district planning of Changping District in Beijing, as shown by the existing geological data. In order to provide the basic geological data for the new district planning and identify the exact location and attitude of the fracture as well as the buried depth of the bedrock on both sides of the fracture, the authors arranged four CSAMT profiles in the study area, obtained a comprehensive explanation of the 4 profiles, and determined the accurate location of the fault. The results show that the CSAMT is effective in buried faults detection and can play an increasingly important role in the exploration of buried faults in urban areas.

Based on the grid data collection, this paper proposes a 3D slice imaging algorithm for rebar concrete component detection by structure scan radar. First, Kirchhoff migration is used to focus so that the reflection wave is returned to its real space position automatically. Then 3D interpolation is carried out to obtain the enough space information of targets for reconstructing with only a few measured data. At last, two direction profiles are fused together to enhance targets response, reduce noise influence, and improve detection efficiency. The detection of experiment platform and true architecture validate the availability and feasibility of the algorithm. The results indicate that exact inner information of rebar concrete component is known comprehensively and meticulously via 3D slice imaging of structure scan radar data. The algorithm can separate dot targets as well as horizontal and vertical linearity targets clearly and supply a credible method and basis for the explanation of radar profile, thus having great significance for relevant detection project and quality identification.

The ground penetrating radar has such merits as high-resolution, nondestructive operation, rapidness and intuitiveness, and these merits play an important role in the quality of grouting testing of prestressed duct. Using the generalized completely Matched Layer (GPML) as absorbing boundary and based on the Maxwell Finite Difference Time Domain methods (FDTD) and Yee grid, the authors made two-dimensional GPR simulation of the water and gas saturated grouting holes with the same depth and different shapes in the steel strand and, in combination with engineering window verification, summarized the characteristics and regularity of duct grouting defects of radar image. The method provides essential foundation for the grouting fullness degree of corrugated pipe tested by ground penetrating radar.

The thin-plate modeling technique can reduce production cost and shorten production circle in physical experiments of seismic exploration. By simultaneous performance of the manufacture and observation,this processing and observation method can decompose seismic wave fields and help us know the propagations of various types of seismic waves in complicated media. This paper reports the manufacture and observation technique of the thin-plate model, discusses the characteristics of wave distribution in the thin-plate model, and describes the seismic wave fields of typical structure models. It is found that the thin-plate physical model has the advantages of simple manufacture and observation, short manufacture cycle and low cost; in addition, the movement characteristics of various seismic waves are obvious and distinct in the obtained seismic wave field map. It can not only simulate various simple geological structures but also help recognize and analyze different kinds of seismic waves during the 3D seismic exploration physical modeling of complex structures.

The effective removal of coherent noise from seismic data has become a problem of much concern. The authors used hybrid radon transform to separate linear noise from seismic section once for all, then eliminated multiple wave in radon domain using adaptive filtering technology and used the inverse hyperbolic radon transform to get the effective reflection seismic signal. Theoretical model and practical data test show that this technology is effective in multiple wave attenuation. Similar function was used to suppress the end effect and truncation effect. The actual calculation results is good and shows that hybrid radon transform can simplify noise suppressing of data processing.

With the production information of seismic acquisition as an example, the author made a comparative analysis of the advantages and disadvantages between conventional input and fast input on the client of SINOPEC Exploration Production Management Information System (SEMIS4.0) and, through bypassing this input mode of the client, improved the input method of information, thus making up the shortage that the input mode of this system client is incapable of realizing the fast input for a great number of records such as surveying data of 3D seismic acquisition. With the improved input method, a great number of records such as surveying data of 3D seismic acquisition can be quickly inputted into the system, and time needed is greatly cut down.

The shallow low resistivity layer has a shielding effect on the detection signal of the transient electromagnetic method; in areas with thick low resistivity overburden, in particular, the completion of exploration task at great depth must be based on the choice of proper technology during the construction and interpretation. In thick low resistance covering layer of North China, the authors conducted the transient electromagnetic exploration and the tests on the construction techniques and data interpretation. It is considered that during the field work, we must select the appropriate loop size and sampling time, use launch power as large as possible to produce a higher signal-to-noise ratio, and that during data analysis and interpretation, MT inversion should be used for prominence of the anomaly. In the low resistance layer with thickness up to 300 m, the authors completed the locating and detection of the water-rich area at the depth of 550 m, and the rich water resources were proved by drilling. The results show that the methods can be used in the low resistance layer water detection in the area affected by low-resistivity overburden.

In Tongling copper mine of Anhui Province, the authors conducted a series of transient electromagnetic exploration immunity tests using GDP-32Ⅱ. Different parameter settings were compared with each other by changing wire size, current, frequency, number of times of superimposition on the frequency and observations, so as to provide an effective measure for obtaining real and reliable data in the strong interference area.

Boolean simulation, which is an object-based modeling method, is mainly used to simulate the distribution of simple geometric objects such as channels and shale interlayers. The program Ellipsim compiled with Fortran computer language is a classic program of Boolean simulation included in GSLIB. This paper deals with the problem as to how to improve the Ellipsim program through the conversion from the sequential method to the parallel method with Visual C#4.0 and Parallel Extension of.NET Framework4.0. It is evident that the parallel program could shorten time consuming effectively from speed-up ratio's statistics with Auto Test Module and Time Consuming Statistics Module. The method introduced in this paper could serve as an guidance for parallel improvement of other simulation programs.

The research on the evolution of sandstone's porosity is the indispensable basis for the analysis of buried history, the palaeotectonic reconstruction and the prediction of palaeo-formation pressure, and accurate acquirement of the primary porosity is the basic prerequisite to achieve the aim. The common method is the empirical relationship created by Beard using sorting coefficient, or the reading of the R.Sneider chart to get porosity and permeability relying on the coring experiment. Based on an analysis of the stress state of sediment particles, the authors set up the primary porosity calculation model with the average particle size ranges as the parameters. Using this model, the authors processed the reservoir sandstone of Chang 8 formation of the Triassic Yanchang Formation in Jiyuan area of Ordos Basin and Bashijiqike Formation in Dabei area of Tarim Basin. A comparison with the previous research results in corresponding areas has verified the reliability of the models.

In field geological survey, the hand-held GPS should be correctly calibrated so as to guarantee the measurement precision. In the work district, the authors uniformly selected 2-3 control points and then correctly input the central longitude and such correction parameters as DX、DY、DZ、DA and DF to fulfill the operation. The authors have conclude that the ratios between the changing rates of the GPS display coordinate X, Y and the changing rates of the correction parameters show certain linear relationship in a certain area. Based on such a linear relationship, the equation-solving method can be used to determine DX、DY and DZ parameters rapidly and accurately. In addition, different DX、DY and DZ combinations can all be used as the proper correction parameters so as to accurately correct the GPS so long as they can satisfy the solution of the equation set.

The authors have obtained a regression equation about one measuring point using the least square algorithm which acts on the electromagnetic field created only by geological anomaly body instead of by mixed signal. The apparent resistivity which is just on the verge of the real electrical resistivity of the coal seam can be predicted appropriately by using this equation. At the same time, the change of the apparent resistivity curve after using least square algorithm is very stable. The value of this new apparent resistivity in the blind area can be used to figure out the value of the observed signal inside the blind zone. Then the response message of unmixed secondary field which is caused only by the geological anomaly body comes out, and this unmixed secondary field can be regarded as the filed separated from the mixed filed, and it brings a much better result at the early stage of advanced detection.

In order to evaluate environmental effects of the chemical speciation of cadmium, the authors studied soils with high content of cadmium in Guiyang, and investigated the crop, water pollution and endermic diseases. Some conclusions have been reached: Cadmium is existent mainly in exchangeable fraction, residual phase, and Fe-Mn oxide phase, subordinately in weak organic combinational state and carbonate phase, and very lowly in water soluble phase. In vertical profile of soil,cadmium content decreases with increasing soil depth, cadmium is more concentrated in surface soil, and the distribution of chemical speciation of cadmium in deep soil is similar to that of surface soil. The water has not been polluted by cadmium in abnormal areas, and cadmium in such crops as rice, pepper and tobacco has exceed the state standard. In addition, local disease symptoms induced by cadmium has appeared in some areas. Therefore, the crops and human health are adversely affected by the high soil background values of cadmium in Guiyang, and the potential threat is serious.

Based on the geochemical data of the surface soil obtained from the downstream basin of the Yellow River in Shandong, the authors used the regular land quality geochemical assessment methods, put forward the assessment value index system of the work area, determined the weights of all assessment index layers, and then completed the land quality geochemical assessment of the work area. Studies show that, as the soil source in the work area is relatively uniform, most of the assessment unit classifications always tend to be the same despite using different assessment index systems, up to 80% land of the whole region can be assigned to excellent grades, and lands of two-ends grades are often smaller and fragmented. The assessment classification can reflect the levels of the soil fertility and healthy elements and, due to the rareness of the soil that exceeds the environment quality standard, the classification simply indicates the relative merits of soil environmental quality. The assessment result can provide guidance for the rational utilization of land resources and provide the data basis and reference for the lower grade stage geochemical assessment within this region in the future.

The integration of seismic survey method with shallow layer profiling method, single-channel reflection method and multichannel reflection method has broad application prospects in the field of offshore engineering geophysical exploration. This paper describes the respective emphases of these three methods and the complementary relationship between these methods and, with the practical example of Shenzhong passageway, expounds the technologies of marine seismic data acquisition, data processing and data interpretation. The engineering application results show the multiple reflection wave technology is an effective supplementary means in the exploration of submarine tunnels, river-crossing channels and sea-spanning bridge locations. It can provide basic data for offshore water area engineering and is also fairly effective in the precise layering of strata and the detection of concealed structures.

Fewer geophysical methods can be utilized in marine project exploration than in the land. Seismic reflection is the preferred geophysical choice. When the submarine sediments are contaminated by shallow gas, the shielding effect of acoustic signal leads to the failure of seismic detection. In this paper, the high density DC resistivity method was adopted to investigate the submarine sedimentary strata as well as the underlying bedrock. The forward and inverse model was built and calculated based on the resistivity borehole logging data, a shallow onshore engineering with this method was conducted and the results show satisfactory results in the submarine engineering exploration. In some parts of the area where seismic reflection works effectively, the authors explained the geology with comprehensive methods, which could ensure the reliability and improve the accuracy of the interpretation.