The distinct difference of magnetic properties between magnetite ores and strongly magnetic volcanic rocks lies in the fact that magnetite ores mainly have induced magnetization, while strongly magnetic volcanic rocks are dominated by remanent magnetization. A method that could allow the remote determination of insitu magnetic properties of sources by using natural geomagnetic variations has been recommended in this paper. Comments are also made on several methods related to interpreting magnetic anomalies caused by remanent magnetization.

With the new understanding of oil and gas geological theories and the rapid development of modern science and technology, oil and gas geochemical exploration technique has also gained active advance in the aspects of basic theory and application extent. The achievements and understanding acquired in basic theoretical study of oil and gas geochemical exploration, method application, oil and gas geochemical analysis and data processing demonstrate that oil and gas geochemical exploration is effective and reliable, and has relatively strong adaptability and great development potential. In combination with the understanding gained in researches on oil and gas geochemical technique as well as related information, the authors hold that the application of this technique to more extensive and complex oil and gas exploration field has raised more harsh and higher requirements for oil and gas geochemical exploration technique. Aimed at tackling different exploration objects and complex conditions, oil and gas geochemical exploration technique itself should have necessary preparation and storage. In addition, integration, insitu investigation and visualization should be implemented in the whole process of oil and gas geochemical exploration.

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

The magnetite resource investigation and drilling verification in Linfen shows that the magnetotelluric sounding method has the advantage of detecting deep highconductivity layer, and hence is effective in prospecting for deep and concealed ore deposits. With a practical example, the authors revealed the relationship between borehole data and low resistance contour lines, and delineated the top and bottom interfaces of the ore body at the depth of 1 400 m as well as the position of the orecontrolling fault. The results show that the inferred depth is consistent with borehole data, with the errors for the top and the bottom being only 3.8% and 0.5%. This is a successful example in the application of the frequencydomain electromagnetic sounding method.

This paper has described the role of largescale highprecision aeromagnetic survey in the prospecting for nonmagnetic ore deposits, made a comparative analysis of the results obtained in Shanting area of Shandong Province by several times of survey which used different scales under different surveying conditions, and summed up their magnetic anomaly characteristics. On such a basis, the authors hold that largescale highprecision aeromagnetic survey can obtain abundant information. It is also thought that, as this method can recognize weakly magnetic geological bodies, it can be effectively used in other fields in addition to the prospecting for  ferromagnetic ore deposits.

Stream sediment survey has been relatively rarely employed in Madagascar. Based on stream sediment oreprospecting work in Ambatongdelazhaka area of Madagascar, the authors probed into the application effect of this method in such geochemical landscape areas. With the stream sediment survey, 147 composite anomaly areas were delineated in Ambatongdelazhaka area, and the delineation proves to be accurate and effective. Titaniumiron, nickel, gold and some other mineral resources were detected through 1∶10 000 field geological mapping and field work, which indicates that the stream sediment survey means is suitable for the geochemical landscape conditions of Central Highlands of Madagascar. The stream sediment survey method can also be  extensively used in the same sort of areas in Madagascar.

Located in Dongchuan of Yunnan Province, the Boka gold deposit contains 16 ore bodies. This research was based on geological and geochemical data in combination with field work. The authors studied geochemical characteristics of trace elements in strata, magmatic rocks and ores, and discussed the genesis of the Boka ore deposit from the angle of geochemistry. Based on an analysis of rare earth elements, the authors deduced the sources of ore minerals, and analyzed the oreforming process and mechanism of the Boka gold deposit.

Chongjiang,  a component part of the Gangdise metallogenic belt, has aroused interest among geologists for its favorable metallogenic conditions and mineral resources potentials. Geochemical information plays an important role in ore prospecting. Based on geochemical data of Majiang in Chongjiang, the authors obtained important information by applying MapGIS and MRAS to extracting geochemical information. The information obtained provides scientific evidence for further anomaly selection and anomaly investigation.

The underground water type of Beier depression is NaHCO3 with low salinity. The water contains many organic compounds such as soluble gaseous hydrocarbon, phenol and fat acid and Br, B and other trace elements. These organic compounds change regularly in the flowing direction of the underground water. The characteristics of water chemistry are obvious abnormal in two discovered oilfields. The data obtained provide a hydrogeochemical basis for the exploration and development of reservoirs through the prediction of hydrocarbon potential in the depression.

The Huzagaitu porphyrytype molybdenum deposit was found by verifying the geophysicalgeochemical anomalies, and the ore bodies mainly occur near the contact zone between the early Yanshanian finegrained granite and the middle Ordovician Hanwula rhyolite. In the mining area, the geophysical and geochemical anomalies have a good combination and a clear hierarchical structure around the granite body. The center of the anomaly is a positive high magnetic field, and outwards there are in succession negative low magnetic field and soil anomaly area, positive low magnetic field and IP anomaly area, and negative normal magnetic field. The geophysical and geochemical anomalies exhibit a good indication of rocks and ore bodies. The magnetic anomalies reflect the distribution of the orebearing granite rocks and the mineralization alteration zones, the soil anomalies indicate the positions of the molybdenum ore bodies, and the IP anomalies indicate the locations of the molybdenum ore bodies and the rhyolite rocks with strong pyritization near the contact zone. Some anomalies were verified with trenching and drilling, 3 molybdenum mineralization belts were discovered, and 5 ore bodies and 3 mineralized bodies were found. The controlled molybdenum reserves have already reached the medium size, and the ore deposit is likely to become a largesize ore deposit. 

In order to improve the oreprospecting effect of aeromagnetic survey in "Yijianglianghe" (one large river and two other rivers) region of Tibet, the authors thoroughly studied the 1∶200 000 highprecision aeromagnetic data obtained in this region by China Aero Geophysical Survey and Remote Sensing Center for Land and Resources and made field reconnaissance in areas of significant aeromagnetic anomalies. On such a basis, this paper sums up the correlation between aeromagnetic local anomalies and ore resources and recounts the effect of direct application of aeromagnetic data to oreprospecting work, which is helpful to geological ore-prospecting work in this region.

In order to probe into harmful geological bodies such as faults, folds, seamthinning areas, collapse columns for the safety of coal mine production, the author designed and developed a highdensity resistivity instrument in accord with the requirements for coal mine explosionproof. Two independent channels, i.e., current channel and voltage channel, were designed. Each channel has two lowpass active filters and two notch frequency filters. Highresolution 24bit ADCs can improve antiinterference capability and measurement accuracy in the circuit. Furthermore, the instrument also has a portable intelligent distributed electrode system, which can flexibly compose a twodimensional measurement system. The instrument has been designed in accordance with the requirements for explosionproof in the coal mine.

The resistivity inversed by the CSAMT method can be used to detect the depth of the strata and deduce the spatial distribution of faults, and even predict the temperature of the thermal structure in some cases. Based on a discussion of the relationship between the underground temperature and the resistivity of the structure, this paper demonstrated the use of the distribution of resistivity inversion to predict the temperature of the geothermal field under certain conditions（with the consideration of the logging data）, and the application results show the effectiveness of the technique.

The study of elastic parameters is an important means in subtle gas reservoir exploration. In the absence of multiwave and multicomponent seismic data, the adoption of rock physical modeling, the separation of P and Swave based on AVO data and the inversion of elastic parameters using P and Swave data constitute a practical and feasible method for predicating elastic parameters. This paper puts forward a new method based on μλ for predicting reservoir, which was used in gas well site allocation in the XC gas field, resulting in the successful  deployment of exploration wells. The results confirm the reliability of the method in predication of subtle gas reservoir. This method hence has a bright future in application.

Based on the exploration of the permanent largescale water supply source area in Yulin City of Shaanxi Province, this paper presents the application effects of such technologies as symmetrical fourpole electrical sounding method, transient electromagnetic method, high density resistivity method and IP method. It is concluded that the application of the integrated electrical technology to the exploration of permanent largescale or superlarge water supply source areas has the advantages of high interpretation precision and reliability, thus being effective in geological work.

The geologic condition is very complex in the North Yellow Sea basin, the seismic data were characterized by poor quality ago, low signaltonoise ratio, the reflection waves of the mediumdeep layer aren't clear, they are not reflected structure of basin. In order to obtain good the seismic data, the choice of acquisition parameters are key. They use a simulation software, Nucleus, to simulate acquisition parameters, for example, capacity and depth of air sun, depth of cable, to combine test in marine seismic acquisition parameters, they confirmed the optimum parameters in the North Yellow Sea basin, and obtain quality data for production.

 In Xi'an City, there are many disadvantages for ground fissure exploration, such as the human's strong influence on environment and the intense background noise interference. In this study, good result was obtained by adopting the controllable vibrator technique and unique data processing technology. Through selecting the optimal working parameters and employing the appropriate measures for suppressing noise, the authors ensured the high quality of the exploration data. In the shallow seismic data processing process, besides the conventional dataprocessing technology, the authors put forward the corresponding technical processing countermeasures for such interferences as vehicle interference, electrical interference, strong energy interference and curve correction. Using the new method of ground fissure exploration, the authors improved the data precision and made a breakthrough in the highinterference fissure exploration under urban conditions. The results also provide reliable geophysical data for studying the formation mechanism of the fissures in Xi'an City.

The transient electromagnetic method (TEM) using the highcurrent and small coil is a mature technology in the prospecting for metallic ore deposits and groundwater. Based on many years' experimental studies, the authors analyzed the causes of negative value V2 (Induction of secondary field) at the top of the fault and put forward the exploration and dataprocessing means for faults, new faults and geological collapses. This paper summarizes the method of TEM for determining concealed active faults (CAF) . Drilling has demonstrated  that this method is convenient in accurate determination of CAF.

 Highresolution singlechannel seismic is one of important methods in marine regional geological survey. It is deployed to discover the shallow stratigrahpy structure, fault, magma active and all kinds of potential geohazards. However, the seismic data is contaminated by different noise. Data processing methods of improving S/N and resolution are discussed in this paper. The processed seismic sections are much better than the original section, which provide high quality data for marine regional geological research.

 With the unceasing improvement of continental oil prospecting, sole use of primary wave can no longer meet the requirement of hydrocarbon prospecting. With the help of primary wave elastic impedance, the authors carried out detailed calculation of the PS converted wave elastic impedance and then analyzed the key parameter of the PS converted wave elastic impedance formula to obtain the density, which can show the gas saturation of the reservoir.

Time, frequency, amplitude and phase differences constitute the main factors affecting the timelapse seismic processing, and elimination of the differences in these four aspects is the key to the unrepeated seismic data processing. The authors analyzed the differences of the construction parameters in two 3D data sets of Yongxin, used the binary corresponding evacuating method to eliminate the differences of field acquisition geometry, eliminated the energy signaltonoise ratio differences between two data sets by targeted denoising technology and energy compensation methods, and used the frequency and phase correction technique to eliminate frequency and phase differences. Based on the four aspects of the mutual constraint processing, the study achieved good results and attained the seismic data processing requirements, thus laying a foundation for subsequent seismic attribute analysis.

A new RBF neural networks model for mineral resource potential mapping is proposed in this paper. For the purpose of applying this new model, a threestep procedure is needed as follows: the first step is to get training samples from the study area; the second step is to abstract the structure of spatial information of training samples and then to construct a RBF networks; the last step is to generate the distributive map of mineral resource potentials. In this paper, the model was employed to predict multimetallogenetic prospecting targets in the area from Duolanasayi to Ashele in northern Xinjiang. The predicted targets by the model were compared with the CF model. The two model results are very similar to each other, suggesting that the new model is effective and practical.

The time domain transient electromagnetic method is an important geophysical method. In combination with its working characteristics, the authors have worked out a series of application software, whose functions include the magnetic field strength computation of each spatial point, field quality calculation of various error statistical data, preprocessing and calculation of various conversion parameters for field observational data. As a result, good geological results have been achieved.

 In longeriod magnetotelluric sounding measurement in the noisy area, the effective suppression of a variety of electromagnetic noises and the improvement of the quality of data constitute the core problem in long period magnetotelluric sounding data acquisition and data processing. As the longeriod magnetotelluric sounding data are characterized by nonlinear, nontationary and noninimum phase, in this paper the authors propose the EMD method to suppress the noise in longeriod magnetotelluric signals, and deals with the implementation details of the EMD algorithm. The authors applied the EMD algorithm to the longeriod magnetotelluric signal noise suppression, and the results show that the EMD method can effectively suppress the longeriod magnetotelluric noise.

This paper mainly describes data transfer for Digital Spinner Magnetometer DSM2 which is a product of Schonstedt Instrument Company of the United States with a computer and software running in the environment of the Windows system. Description is also made concerning the related technical theories and train of thought such as paleomagnetic geophysics, intensity of magnetization, dip angle and angle of declination. An analysis is made concerning the instrumental construction in DSM2 and the principle for connecting it with the RS232 of the  computer. The software development process and the detailed contents are also discussed.

 The multiwave multicomponent seismic exploration technology is an effective means for comprehensive utilization of P wave, convertedwave and other seismic waves. The processing steps for convertedwave separation and extraction are essential. In this paper, using the multicomponent simulation data of the geological model, the authors conducted separation and extraction experiments on the P—SV converted waves. For multiwave multicomponent wave fields with different characteristics, different separation methods can be used.

 On the basis of the deconvolution principle，this paper has deeply studied the theory of Burg deconvolution and inferred and derived the formula of Burg deconvolution in detail. Using the method for processing real seismic data and comparing the processed result with the result obtained by the method of spectrum simulating convolution, the authors have found that the method can improve signaltonoise ratio of seismic data, enhance the continuity of reflection events and surpress the linear interference included in seismic data, so the method can improve the quality of seismic data to some extent.

Since Caledonian movement, the earth's crust in Henan area has been uplifted for so long time that the denudation of CambrianOrdovician strata has lasted for 140 Ma, which has provided preferable environmental conditions for the formation of bauxite. The material sources of bauxite were derived from both carbonate rock basement and silicate basement. Some changes of active elements might have taken place during the weathering, immigration and sedimentation, whereas for the stable elements certain connections did exist before weathering and after sedimentation and mineralization, especially for the ratios of the stable element couples. On the basis of a study and stimulation of the oxidation couple ratios between carbonate rock basement, silicate basement, aluminumbearing rock series and bauxite deposits, the material sources of bauxite can be judged. This is a quick and convenient mathematic statistic method for judging the material sources of the bauxite.

The nondestructive detection of underground objects has long been an important problem in urban construction in that it is related to the safety of the underground objects and constructions. Based on practical applications, the authors have found that highdensity resistivity is an effective method to detect urban underground objects.The features of the resistivity image are similar to the shape of actual objects, and the interpretation is easy. Based on the exploration of such underground objects as underground pipes and canals, airraid shelters and other underground construction structures, this paper gives a comprehensive discussion on the application of highdensity resistivity to detecting the urban underground objects.

 Some unknown structures are always uncovered and gas outburst or water bursting can easily take place during the tunneling of mine roadways rich in gas or water, which seriously influences the safety in coal mine production. On the basis of the theory of whole space "smoking ring effect" of the mine transient electromagnetic method (MTEM) in roadway and according to the limited space around the roadway head and the exploration environment of the interference of other metal facilities, the authors chose MTEM to detect geological structures in front of roadway head, and systematically studied the detection devices as well as detection and graphical display techniques of advanced detection of MTEM in tunneling mine head. Practical application shows that the exploration results are well consistent with the uncovering situation of the roadway