Some important models of the Earth' s lithospheric magnetic field, such as MF series, CM, POMME series, NGDC-720 and EMAG2, are reviewed in this paper. Global CTD map compiled by Dr. Purucker and Dr. Fox Maule and the CTD map of China's mainland compiled by Prof. Hou and her colleagues are highly recommended.

The Xishanwanyangchang silver deposit was discovered by means of 1∶50 000 stream sediment survey and identification of geochemical anomalies.Ag anomaly has high peaks, high values and good continuity, and anomalies of Ag, As, Sb, W and Au fit better, with concentration and component zonation. Rock geochemical profile survey was conducted in the anomaly area, distinct anomalies of Ag, Au and As etc. were discovered, and ore bodies of Ag were delineated by trench exploration. Ore bodies of Ag were identified by means of drilling, and the ore deposit is controlled significantly by faults. Rhyolite, rhyolite porphyry and rhyolite breccia are main host rocks.

Magnetic method, very-low frequency electromagnetic method, transient electromagnetic method and IP sounding were employed to carry out gold prospecting and evaluation in an old gold ore district of Lingbao County, Henan Province, according to metallogenic geological conditions. Based on an integrated analysis and study of the geophysical data as well as the integrated geophysical prognostic criteria, the authors delineated six ore-prospecting target areas, which were proved to be related to gold mineralization by four drill holes. Ore-prospecting breakthrough was achieved in the shallow and middle parts of Fancha H8703 gold-bearing faulted zone of the Xiao Qinling Mountains, and a mine was brought back to vitality. It is proved that geophysical exploration is an economical, rapid and effective means in search for shallow and deep concealed or semi-blind ore deposits and hence deserves further popularized application.

The preliminary study of the geochemical features of Fukeshan region was based on the 1∶50 000 stream sediment survey.Through a study of the element distribution features, the authors hold that the area has the potential of finding Au, Pb, Cu and Sb ore deposits and mineralized bodies. The study of the anomalous characteristics combined with the ore-forming geological conditions and existing mine information shows that there exist two main metallogenic types in this area: one is probably gold deposits related to quartz veins in granite, and the other is probably Cu, Pb and Sb polymetallic deposits related to basic-ultrabasic rocks and the metamorphic Xinghuadukou Group. Then the authors divided the study region into Fukeshan, west side of Fukeshan River, and Dalin River gold metallogenic prospective areas as well as Huoluotai River, Huoluotaichiku River, and Huoluotaishan Cu, Pb and Sb metallogenic prospective areas.

The application and study of the downhole transient electromagnetic method remain very insufficient in China. In order to demonstrate the effectiveness of this method and further promote its application under the situation of increasing exploration depth, the authors chose the Huangshanling ore district in Anhui Province and the Tonglushan ore district in Hubei Province as the study areas. As a result, a good anomaly related to blind ore body beside the well was found in Huangshanling, and the extension of the ore body at the depth of 18200 m was detected in Tonglushan. The two instances demonstrate that this method can detect blind ore bodies and trace the extension of the ore body. Therefore, this method is worthy of promption for deep exploration in China.

The Gonghe-Guide basin of Qinghai Province is located in a Cenozoic graben basin of the Qingling-Kunlun orogenic belt, where there are many active faults,magmatites and intense hydrothermal activities. There are 6 hot springs whose temperatures are over 60 ℃, with the hottest one reaching 93.5 ℃, which is beyond the local boiling point (92 ℃) and is hence defined as a boiling spring. The geothermal field is high in this basin. According to three geothermal drill holes that uncovered granite, the drill hole named QR1 969 m in depth exposed 70 ℃ at the bottom, the drill hole named DR1 1 455 m in depth exposed 87 ℃ in the bottom, the drill hole named R2 1 709.56 m in depth even exposed 97 ℃ at the bottom. Geothermal gradient is up to 6-7 ℃ per 100 meter, being two times of the normal gradient. The geothermal warming increases with the depth, and the authors inferred that the temperature in the depth of 3000 m is about 150 to 200 ℃. The basement depth inferred by low gravity anomaly is not consistent with the CSAMT and seismic reflection results. With corresponding magnetic anomaly and drilling evidence, the authors believe that the gravity and magnetic anomaly is caused by Yanshanian granite. As the deep drill holes intersect heat but no water, the authors hold that there may exist hot dry rock as the heat source of this basin.

Based on systematic collection and integrated analysis of data available, the authors conducted 1∶2 000 geological modification survey in the key metallogenic segments of the Chencun ore district in Miaoxia, Longyou County, Zhejiang Province, and used integrated methods composed of geological investigation, geophysical-geochemical exploration and drilling to understand the modes of occurrence of Miaoxia fault beneath the Quaternary overburden, the distribution of ore-bearing structure alteration zone and the possibly-existent concealed porphyry under the acid dyke group. There were two geochemical and geophysical anomalies of much metallogenic potential to be delineated.The high abnormal of Pb, Zn in surface soil, mineralized alteration zone and mineralization zonation, especially the 5 layers of lead-zinc mineralization body found in the ZK001 drilling of view showed that the mine is favorable locations to carry out deep prospecting work.

Re-understanding of the gravity anomaly of the Linxiang polymetallic ore-forming area in northeastern Hunan Province and its geodynamic mechanism was obtained mainly by means of vertical second derivative. The authors inferred the distribution of the structural framework and the concealed rock bodies of the study area, summarized the relationship between the gravity anomalies, the concealed rock bodies and the fracture structures in the known ore spots (ore bodies). It is concluded that there still exists the potential of finding large polymetallic deposits. The results obtained by the authors provide important geophysical evidence for deep ore prognosis.

The Gangdise volcanic magmatic arc is an important copper-polymetallic prospective area. The deposits are closely related to intermediate-acid igneous rocks. It is important to evaluate aeromagnetic anomalies caused by igneous rocks. This paper studies the aeromagnetic features of two typical porphyry deposits in South Gangdise (Jiama and Qulong) by three-dimensional inversion of magnetic data. Combined with previous achievements, this paper concludes that the upright rock and back magnetization constitutes the principal feature of these two deposits. On such a basis, in combination with the distributional regularity of porphyry copper deposits in South Gangdise, this paper predicts porphyry copper deposits of this type by Hough transform., and delineates 18 potential prospecting areas, thus providing important information for mineral exploration.

This paper describes briefly the technology of the measurement and interpretation of ground electromagnetic wave CT through the survey conducted in 7th ore body group of the Norbusa chromite deposit. The position, extension, strike and dip as well as the connection of ore bodies on cross-hole section can be detected and blind ore bodies on cross-hole section can also be found by ground electromagnetic wave CT. The test results prove the feasibility and effectiveness of the electromagnetic wave CT in the exploration of chromite deposits.

Large-area iron-manganese mineralization is developed in Ajile-Ulan-Bogen Obo area of Dong Ujimqin Banner in Inner Mongolia. The in-situ measurement of soil and rock outcrops in this area by means of X-ray fluorescence instrument revealed the consistency between the anomaly concentration centers of quite a few elements and the known ore veins, the trenching performed over anomalies outside the ore veins led to the delineation of new ore bodies, and the drill hole intersected several layers of veined and stockwork ore bodies. If rational methods and techniques are adopted to correct the matrix effect, and the influence of the humidity effect and the geometric effect can be overcome as much as possible, the measurement result of the portable X-ray fluorescence instrument can reflect the reality of the ore district, which is hence of great practical significance for rapid delineation of ore prospective areas, tracing and verification of anomaly points (zones) and direct delineation of ore bodies in anomalous areas where values of ore-forming elements are higher than their ore grades.

Magnetic susceptibility data play an important role in the process of interpreting aeromagnetic anomaly. In order to better application of the high precision aeromagnetic data obtained in West Tianshan Mountains, the authors measured magnetic susceptibility at more than 500 points, and made a systematic arrangement and statistic analysis of these data. The magnetic susceptibility features of rock and ore were studied in the light of strata, lithology and ore. Based on the magnetic susceptibility data, the authors delineated hundreds of magnetic strata and identified 221 concealed or semi-concealed intrusive bodies. The authors inferred 109 magnetic anomalier of iron deposit and found more than ten iron bodies in West Tianshan Mountains.

As a main parameter of magnetotelluric sounding, the impedance phase has strong capability of resisting disturbance and high resolution in comparison with apparent resistivity. In this paper, through analyzing the relationship between the apparent resistivity and the impedance phase,the authors derived the recursive formula of phase apparent resistivity and analyzed the important properties of the impedance phase. With the processing and interpretation of magnetotelluric sounding profiles data measured in Yin'e basin as an example, the authors used phase recursive apparent resistivity and corrected the distortion of the apparent resistivity curve in the low frequency. It is shown that the apparent resistivity residual static effects have been better suppressed. Using the extreme point of the phase curve, the authors accurately determined the low-impedance Cretaceous layer interface, made up the inadequacy of the apparent resistivity data in interpretation, and described the application for impedance phase in the magnetotelluric sounding data processing and interpretation.

The AMT method is used widely in metal mining and groundwater as well as environmental engineering survey. According to AMT signal characteristics and on the basis of previous research results, the authors developed AMT signal recorder independently by relying on the existing AMT magnetic sensors and electrodes. This paper described the recorder related to the key technologies of hardware and software, and made a comparison with similar instruments abroad through field test. The results show that the indices of the independently-designed ATM instrument can meet the standard AMT instrument measurement requirements basically.

In this paper, a FPGA-based GPS synchronous signal generator for the calibration of MT instrument is presented. Under the control of AT91RM9200 processor, five square wave signals with specific frequencies of 0.09375, 0.2344, 2.5, 20 Hz and 24 Hz for calibration can be generated, and are synced with GPS's PPS. Multiple frequencies calibration is all done at the same time due to the nature of square wave composed of extensive odd harmonics. We designed a SPI interface to realize the communication between FPGA and AT91RM9200. The soft IP processor PicoBlaze, as the control center inside FPGA, is employed to analyze and process the control parameters, and to control the synthesis of frequencies and their synchronization to the rising edge of PPS. The synthesized square signal is transmitted to the analog channel board through photon-coupled isolator. As the test result proves, the signal generator works well, and calibration signals have a lag of less than 1.5μs to the rising edge of PPS, more-than-10 MHz bandwidth and stable amplitude, which meets the calibration requirement.

The authors studied the winding method, preamplifier and damping method of the induction coil and developed an inductive coil 100 mm in diameter. The results of the field and laboratory tests show that the technical characteristics of the inductive coil are the same as the mature coil. The new sensor is very easy to use in the field.

In view of the characteristics of traditional central gradient IP method, such as high efficiency and less data amount, this paper puts forward the multiple electrode distance central gradient survey method. Using the existing multi-channel transmitter and receiver with a little additional work, this method can get more apparent resistivity and apparent polarizability data to realize 2D inversion imaging. The inversion results of modeling and measured data have shown that the multiple electrode distance central gradient survey basically has the same effect as the symmetric four-pole sounding, and at the same time can improve work efficiency multiply. So, the multiple electrode distance central gradient survey can be applied widely.

Dajingpo Airborne Geophysical Test Site is the first airborne geophysical(magnetic, gravity and electromagnetic)integrated test site in China, at the sponsor of 863 project. The selection of integrated test site is an important and difficulty work, because it need to consider of all the conditions for the test of magnetic, gravity and electromagnetic systems. Therefore, the selection of integrated test site need to consider the basic principles as follow: the interfere is small in the test site and around; there is diversity in topography; there is affluent in geology, and possess of iron points (or iron deposits) are best; magnetic, gravity and electromagnetic abnormities are obvious., and so on. According to the basic principles and methods of "Select a large region first, and the site wherein ", after the synthetical analysis and contrast in topography, geology and geophysical materials and check in field, Siziwangqi Test Site is filtered from all the county, then do more detailed work to Siziwangqi Test Site, Dajingpo Test Site is determined in the Dajingpo area at the NE corner of the Siziwangqi Test Site.

The method of model-based seismic inversion makes use of sound velocity logging or density logging constrains to get wave impedance inversion information.However,when the difference between the purpose layer and the surrounding rock is small,it is difficult to solve the problem of layer contrast through the information.In fact,apparent resistivity and artificial gamma logging can provide lithological information of other strata.The inversion constrained by multiple parameters has more acute effect in distinguishing lithologic characters.The method of double logging curve fusion makes use of two different logging curves to fuse and transform into a imitated density curve,which can highlight the density anomaly of coal and magmatic rocks at the same time.Multiple parameters lithological inversion can be realized by the imitated density curve constraint.

It is obvious that the shot density and receiver density are very important to the cost, but the effect of the shot density and receiver density on imagery remains unclear. The authors studied the effect of the shot density and the receiver density on imagery, and reache d the conclusion that the property of the 3-D geometry, rather than the shot density and the receiver density, is important to imagery. It is suggested that we can adjust the shot density and the receiver density to reduce the cost under the condition that the fold and the bin are not changed.

It is important to measure quality factor Q in the processing of seismic wave propagation and the predictiing of hydrocarbon. In practical production, the most commonly used to estimate quality factor Q is spectral ratio method. However, the traditional spectral ratio method is facing windowing problem. In this paper, the authors took the advantage of superior time-frequency characteristics of the S-transform and the direct linkage between the Fourier spectrum and the S-transform to extract the corresponding instantaneous spectra of the upper and lower interfaces of the formation. Then by fitting the relationship between frequency and amplitude ratio, the authors estimated the quality factor. Numerical simulation shows the effectiveness of this method.

Geological structure is complicated in the north yellow sea basin.In the reflection seismic data obtained from some areas,the deep reflection is unclear,leading to multiple solutions in seismic data interpretation.In this paper,the authors analyzed the difference and connection between travel time curves of the reflection wave and the refraction wave,made the most of the potential of seismic reflection data,used their refraction data,analyzed refractive characteristics of the basin,and calculated the velocity of the basement,to make up the weaknesses of the velocity analysis of the reflection data.The refractive wave velocity was used to infer geological attributes and divide seismic horizons.The results obtained improve the precision of the intermediate and deep horizon seismic data interpretation in the north yellow sea basin,and make the seismic data interpretation more reasonable.

Soil geochemical background investigation was carried out in the scallion growing area and planned scallion area of Zhangqiu. It is found that the surface soil of these areas has high level of Se, B, P, N, S and low level of F, Mo, CaO. The richness of the beneficial elements, especially Se, constitutes the favorable prerequisite for the development of a Se-rich agricultural base area. Soil fertility status and environmental quality in the region are both good, Se and heavy metal elements values in scallion have a close relationship with their values in soil. A comparison with the green and pollution-free food producing soil standards shows that the survey area land has a high degree of security, which makes the area very suitable for the scallion cultivation. On such a basis, the authors put forward the Se-rich scallion planting plan for Zhangqiu, and the whole work region can be divided into four planning areas: the most suitable area, the comparatively suitable area, the somewhat suitable area and the unsuitable area. The feasibility of developing Zhangqiu Se-rich scallion is discussed in this paper, which may be used as a reference for optimizing the cultivation of Zhangqiu Se-rich scallion and making the plan for further development.

Field measurement of soil radon concentrations was carried out and the corresponding soil samples were collected in Zhuhai area for analyzing uranium content. The linear simulation was used to analyze the measured data. The result shows that soil radon concentrations are positively correlated with the uranium content of the soil. The probability of soil radon concentrations greater than 20 000 Bq/m³ has a good linear relationship with uranium content of soil. The level of the soil radon concentrations is influenced by a number of factors and the measured values are not stable, and hence the study of the probability of the excess is more scientific. According to the relational model and risk classification, we can quickly evaluate regional soil radon hazards.

With the soil element content distribution in Zhangye-Yongchang region as the main basis and on the basis of analyzing the soil pollution situation and the status of the beneficial elements in the survey region, the authors selected six kinds of soil quality evaluation indices, such as necessary major elements, necessary trace elements, beneficial elements and harmful heavy metal elements, and, according to the weight threshold calculated results of various indices and the membership function calculation model, divided the soil quality of the survey region into five grades, i.e., high-quality, superior, fine, moderate and bad, which possess 4.88%, 47.21%, 29.08%, 14.49% and 4.34% of the total area of the survey region respectively.

On account of the influence of natural and man-made factor, there have been serious geological diseases in Dazu Rock Carvings. The paper expounded the application of geophysical technologies in the conservation of Dazu Rock Carvings, including high-density resistivity method, electromagnetic wave computerized tomography (CT) technology,borehole television technology and geological radar technology, and so on. The plane distribution rule of the main water bearing structures, the spatial distribution pattern of the aquifer, the distribution of the Quaternary overburden and the structural characteristics of rock masses which the rock paintings occurreto was ascertained through the methods mentioned above. A ideal results is achieved and provides the basis for the conservation of Dazu Rock Carvings.

The application of integrated geophysical prospecting technique to the investigation of ground fracture hazards was described in combination with the ground fracture hazards project. The geological problems that can be solved during the investigation of ground fracture hazards, the extent of solution, the applicable conditions and the accuracy show that the integrated geophysical prospecting technique is an digitalized high precision means to solve the problem of ground fracture hazards.

The concentrations of H₂ in soil gas were surveyed along two lines, which crossed the known Yinchuan buried fault. The maximum abnormal concentration of H₂ lying at the Xinqushao trench of the Yinchuan buried fault in soil gas was 73.6?10^-6. It is suggested that the abnormal concentrations of H₂ in soil gas were mostly influenced by the dip angle of the buried fault and the activity of the fault. Soil gas H₂ measurement has certain indicative significance for the buried fault.

Simulating the behavior of ant colony searching for food, the Ant Colony Algorithm is an emulated and optimized algorithm, which demonstrates excellent performance in such combinatorial optimization problems as Traveling Salesman. However, it has not been widely applied to the inversion and interpretation of magnetic data. Based on the characteristics of magnetic data inversion and interpretation, this paper improves the mapping mechanism from objective function value to pheromone and summarizes Ant Colony Algorithm optimizing for continuous and multiple objective function using nodes partition strategy. Satisfactory results were achieved when Ant Colony Algorithm was simulated to inverse the parameters in the synthetic model experiment of magnetic data and was applied to prospect the banded iron formation according to low-altitude aeromagnetic data surveyed at Iron Mount mining area, southern Australia.

In view of the existence of a series of common problems in the current geophysical database system, such as the complexity of professional data structure design, the requirement of data processing and the lack of effective management of specific outcome data, the authors carried out the design and implementation of Magnetotelluric Sounding (MT) result database based on the deep lithosphere structure. On the basis of the basic theory of MT, database technology and computer technology, the authors collected, trimmed, analyzed and modeled MT data that are the major regional deep exploration data, and, on such a basis, designed and developed the MT database system based on SQL Server 2005 and Visual Basic 6.0. Some basic functions of the system that include retrieval, query, edition, and input / output can be achieved quickly and easily, and other functions of the system that include MT storage and visualization can be operated as well. Meanwhile, this MT database system can play an important technical support role in the study of China's lithosphere structure and geodynamics as well as the study of tectonic evolution of the Earth.

The selection of technical parameters for the vibroseis affects considerably the quality of the seismic data acquired from seismic exploration. The Matlab GUI design was adopted to simulate the influence of various parameters (such as scanning signal type, frequency range, signal phase shift and amplitude distortion) on the signals produced. The change of the parameters of scanning signal in the graphic interface can be conducive to the comparison and analysis of vibroseis scanning signal simulation waveform under the condition of different parameters.

This authors describe a more efficient and adaptive high frequency noise suppression method in which a new adaptive threshold technique is combined with a continuous thresholding function to overcome the shortcoming that existing threshold de-noising technique by wavelet transform is not suitable for seismic data.The continuous hard thresholding function can combine both advantages of soft thresholding function and hard thresholding function,so it can enhance the fidelity of reconstructed signal and reduce the artificial noise.An adaptive threshold scheme is carried out by analyzing the statistical parameters of wavelet subband coefficients like standard deviation,arithmetic mean and geometrical mean in different subbands,which is based on the time-varying and spatial-varying energy distribution feature of nonstationary seismic signal.This threshold can adjust itself automatically with the variation of wavelet coefficient energy in different subbands to meet the requirement of high frequency seismic noise suppression.The actual seismic data processing result indicates that this method can not only raise the signal-to-noise ratio but also protect thoroughly the steep dip angle reflection event and enhance the fidelity of seismic signal after noise elimination.

Based on integrated utilization of the logging,seismic and geological data and taking the petrophysics analysis of single or multi-wells as the starting point, in combination with seismic horizons,the authors used logging curves to establish reservoir elastic model for forward simulation,made a comprehensive analysis of the response characteristics of reservoir/oil-gas geophysics,and conducted rapid color inversion.The results obtained can not only verify the achievements of seismic interpretation but also be comparable with the inversion of impedance.This technology shows a good application effect in Sujiatun area.

The seismic data recovery from data with missing traces plays an important role in the later stage seismic processing.The authors studied the sparse transform (F-K transform and Curvelet transform) and popular compressed sensing theory,and then combined the two methods together to build the seismic data recovery model which is based on sparse transform.The F-K transform changes the seismic data from the t-x (time-space) domain into the f-k (frequency-wavenumber) domain.Because of the favorable directionality and locality and multidimensionality,the curvelet transform can represent the seismic data in a more compressible way.On the basis of the recovery model,the missed seismic data are recovered by the two sparse transforms and the recovery results are compared and analyzed.The recovery results prove that the Curvelet transform recovery can get the better reconstruction effect than the F-K transform.Finally the Marmousi2 model and practical seismic data are processed,and the result shows that the seismic data recovery model is correct and effective.

This authors introduce the basic principle,data acquisition and processing method of sound wave computerized tomography(sound wave CT),and then makes a detailed discussion on the applied effect of sound wave CT in geological regional detection of an extra large water gushing channel in a certain hydropower station diversion tunnel.Practice shows that sound wave CT can effectively remedy the limitation of single-hole sound wave test,and the result images of sound wave CT describe vividly the position and scale of the gushing channel of ground water.Thus,sound wave CT can successfully detect similar geological problems and provide scientific basis for the follow-up construction design.