The Qian'echong molybdenum deposit is a superlarge concealed porphyry deposit recently discovered on the northern slope of the Dabie Mountain. Based on a review of about thirty years' prospecting process from the discovery of the deposit to the prospecting breakthrough, the authors studied the ore-forming geological features and the characteristics of regional anomalies, local anomalies and primary anomalies. The geochemical ore-hunting indicators and patterns of the deposit were also summed up. The prospecting practice of the deposit demonstrates that geochemical exploration for porphyry molybdenum deposits is quite effective. The 1:200000 and 1:150000 stream sediment survey and the 1:10000 soil survey as well as the rock drilling survey all could uncover the indicating elements of porphyry molybdenum deposits, which serve as excellent ore-hunting indicators.

1:50,000 stream sediment survey in Hoos Braque area revealed distribution patterns, enrichment and dispersion regularity of the major ore-forming elements in this area. On the basis of analysis of regional metallogenic conditions, the Hs46b₂ composite anomaly was preferentially picked out for geological integrated prospecting, and a new medium-sized karst breccia type lead-zinc deposit was found in northern Qiongqia Te area. The newly-discovered deposit is helpful to the prospecting for the same type of deposits in carbonate formations along foreland thrust-fold belts in southwest Tianshan Mountains.

Located in the North Qilian orogenic belt, the Tongchanggou gold deposit is controlled by the tectonic altered zone and belongs to a small tectonic altered type high-grade gold deposit. Through field work, a mineralized alteration zone was discovered in the western mining area. Sample analysis along three sections shows obvious manifestations of mineralization and alterations, gold content in primary halo samples is the highest (0.2 ~ 4.5)×10^-6 and that in secondary halo soil samples is 0.1×10^-6, with silver also showing obvious abnormal display. Various chemically treated data all lie in the 3rd mineralized alteration zone with a turning point, indicating that the 3rd mineralized alteration zone is a geological body with certain extension. Through induced electric medium gradient method, it is found that the high polarization and low resistivity anomaly extends through the 3rd mineralized alteration zone. Geological, geochemical and geophysical data are consistent well with each other, which suggests that there still exists some prospecting potential, and future work should focus on the 3rd mineralized alteration zone.

With the discovery of the Chengping molybdenum deposit in Xifeng County of Liaoning Province as an example, this paper expounds in detail the important role played by geochemical (stream system, soil) survey in the determination of ore-prospecting targets and metallogenic types as well as the prospecting for the concentration segments of ore (mineralized) bodies, and the application effects of IP intermediate-gradient survey in reflecting the relative enrichment of underground metallic sulfides and the intensity of silicification with the granite body. The full utilization of geophysical and geochemical methods can reduce the multi-solution in anomaly interpretation and make the anomaly interpretation more reasonable, thus achieving good prospecting result.

The main reservoir can be affected by high radioactivity minerals in the T oil field of Middle East; as a result, shale content cannot be calculated exactly by natural gamma log data. In addition, it is difficult to confirm clay types of each main oil-bearing reservoir because of insufficient core analysis data. To tackle these problems, the authors used the close relationships between clay minerals and uranium, thorium, potassium from natural gamma ray spectrometry log to reasonably calculate argillaceous matter content by thorium and potassium content. According to the interpretation charts of Schlumberger, the clay types were defined by using Th-K crossplots, and depositional environment was studied by making Th/U histogram, with satisfactory results achieved. The results obtained by the authors provide dependable reservoir evaluation data for late development of oil field.

Iron ore prospecting work with gravity and magnetic methods is generally very effective, but in the Quaternary cover area ultrabasic rocks would produce gravity and magnetic interference, which often causes the miscarriage of justice. Therefore the key problem in such an area is to distinguish the gravity and magnetic anomalies caused by basic rocks and those casued by iron deposits. With the exploration of the Duhaotuo iron ore deposit in Luannan area as an example and through the processing of magnetic and gravity data, the authors analyzed the basic rock gravity and magnetic anomalies and their masking effects on ore anomalies, and summarized the methods for identifying iron anomalies. Drilling demonstrates that the means put forward by the authors are reliable and applicable, and the results achieved by the authors will be significant for ore-prospecting work in the future.

The regional geological and geophysical exploration work in Chile remains at relatively low level, the interpretation of mining area geophysical data is insufficient, and the distribution characteristics of ore deposits are not clearly known. The authors made a comprehensive analysis of the geological and geophysical characteristics, and employed the geophysical ground magnetic and electromagnetic measuring method in the X ore district of the first region of Chile. It is held that the relatively high magnetic or weak magnetic low resistivity anomaly zone and its depth and surrounding areas are geophysical anomaly indicators for ore prospecting, and that the structure (shatter zone) should be the focus in further study of the metallogenic regularity. Geophysical exploration methods are of guiding significance in the practical exploration work.

The integrated geophysical and geochemical prospecting methods are faced with challenge from complex geological condition, A single geophysical or geochemical analysis method is not persuasive, and hence the integration of various geological information and exploration methods is particularly important. The application of the integrated geophysical prospecting method system to a deposit in Henan Province is described in this paper based on practice. According to geological data and concrete geological facts, geophysical methods such as high precision magnetic survey, X-ray soil analysis and EH4 were used in an integrated way for concealed ore body prospecting. A clear geophysical and geochemical anomaly is related to metallization and matches well with geological phenomena, which suggests that the integrated geophysical and geochemical prospecting method system is effective in the molybdenum deposit, and it has the advantages of rapidity, efficiency and practicality.

EH-4 continuous conductivity imaging technology was employed in search for concealed orebodies so as to achieve a breakthrough in the Xiangutai ore deposit. The prospecting for copper-polymetallic deposits was preceded by the search for porphyry concealed rock masses. It was found that the granodiorite porphyry has three kinds of anomaly marks in the resistivity reversion sectional drawaing: in the transitional zone from high resistance to low resistance, there appear contorted deformation segment, localized high resistance segment in low resistance area and localized low resistance segment in high resistance area. Anomaly interpretation and drilling verification were conducted along three typical profiles, with fairly good geological results achieved. The results show that the application of EH-4 continuous conductivity profile measurements to the ore district has obtained a wealth of abnormal information, achieved good geological effect, and provided geophysical basis in search for porphyry copper polymetallic ore deposits.

The exploration of deep concealed ore deposits is the main task at present. A lot of electrical measurements have been completed in Xilin Gol League of Inner Mongolia in recent years, which mainly consist of high-power IP and CSAMT or their combinational methods, with good prospecting results achieved. High-power IP measurement was used for discovery and delineation of mineralization limits and distribution of structures in the ore district; Inversion of resistivity of CSAMT section was conducted to deduce underground electrical characteristics of lithology, geological structure, attitude of structure, and size and space of ore (mineralized) body. The results achieved by the authors provide the basis for the drilling. This paper describes the exploration process of a certain deep concealed lead-zinc deposit in Inner Mongolia and makes interpretation.

Fengquan district in Xinxiang is one of the areas in China characterized by shortage of groundwater resources. To tackle this situation, the authors applied the combination of high density resistivity method, EH-4 conductivity sounding and induced polarization of symmetrical quadrupole to groundwater resources prospecting in loose rock and bedrock regions, and achieved remarkable results under complex hydrogeology conditions. The experience gained by using the combination mode of different electrical methods for water prospecting under different hydrogeological conditions was summed up in this paper. The application of combined mode provides reliable and scientific basis for determining location of well in the process of groundwater prospecting, and also guarantees high success rate in well drilling.

Shanqipan area is located near the NS-trending molybdenum anomaly zone from Qian'echong in Guangshan County to Shangqipan in Xinxian County. The region has good molybdenum ore prospecting potential. The authors made a comprehensive analysis of the combined features of stream sediment geochemical survey at the scales of 1:200000 and 1:50000, with emphasis placed on the soil geochemical survey at the scale of 1:10000. An evaluation was also made on the soil geochemical element association by index of geoaccumulation. Trenching and drilling verification led to the discovery of 7 molybdenum orebodies, thus achieving satisfactory ore-prospecting results.

The authors analyzed the element distribution characteristics, element correlation and geochemical mineralization model of ore spots in Chimanimani area of Zimbabwe by means of stream sediment survey, established the regression model for gold and associated elements,and delineated 6 metallogenic prospective areas according to the abnormal features and regularity of spatial distribution and through optimization, with Tarka prospective area as the potential area of hydrothermal alteration type gold deposit,and the other 5 areas as the main exploration targets for copper, nickel, titanium deposits.

To well understand the deep structure environment and mechanism of strong earthquakes occurred in the Tianshan-Mongolia-Lake Baikal seismic belt, an integrated geomagnetic and gravity survey was conducted along the profile from Suhbaatar to Ulaanbaatar to Dalandzadgad in Mongolia. In this paper, petrophysical parameters (bulk density, magnetic susceptibility, intensity of natural remanent magnetization, and Köenigsberger ratio) of 585 rock samples collected from this profile are summarized. Results indicate that significant density contrast of different rocks would result in variable gravity anomalies along the profile. Magnetic susceptibility and natural remanent magnetization of all rocks are variable, covering 3~5 orders of magnitude, which would make a variable induced magnetization and further links to complex magnetic anomalies in ground surface. These petrophysical parameters provide essential constraints on the interpretation of geophysical data and to calibrate geophysical parameters.

Inner Mongolia has vast territory and, according to the theory of plate tectonics, strides across Siberian, North China, Kazakhstan and Tarim plates. Its tectonic environment is extremely complex in that it has experienced multi-period structural movements in geological history. For years, the boundary between North China and Siberian plates has been a discussion hotspot among geologists. Based on an analysis of the geophysical gravity and magnetic field characteristics of the suture zone, the authors hold that Xar Moron River fault zone should be the ultimate suture zone between North China and Siberia plates. The results obtained by the authors provide geophysical evidence for the determination of the ultimate suture zone between the two large plates.

With C-1980-6-2 as an example, this paper elaborates the technical route in the search for sulfide deposits during the anomaly ground verification in 1:50000 airborne geophysical integrated survey along Erenhot-Dong Ujimqin Banner metallogenic belt, describes in detail the whole process of anomaly verification, and deals with the main interference factors in applying induced polarization method of carbonaceous anomaly to prospecting for sulfides and their elimination.

Based on the scale of 1:200 000 regional geochemical exploration data obtained from Sanjiang region in Yunnan Province, this paper describes geochemical characteristics and the potential of mineral resources in combination with the regional geology and metallogenic regularity, and discusses the key elements related to copper and copper-polymetallic deposits. The metallogenic elements in the area mainly include Cu, Zn, Pb, Cd, Ag, As, Sb, Hg, Be, W, Sn and Bi, some of which are copper-associated metal elements, such as Cu, Pb, Zn, Cd, Ag, As, Sb and Hg are related to magmatic activities and sedimentary and hydrothermal alteration. Above all, the copper target areas for exploration in near future are delineated, which include five Grade Ⅰ areas, six Grade Ⅱ areas and three Grade Ⅲ areas according to the three typical copper or copper-polymetallic deposit models for filtering and evaluation by GIS technology.

Pre-stack seismic inversion seems to be the main technique for reservoir fluid identification; nevertheless, there exist problems such as petrophysical weakness and multiple solutions in its application to investigating geological features of the specific study area. In order to improve the precision of seismic identification of fluid, the author carried out studies of typical reservoirs in such aspects as petrophysical basis and prestack seismic inversion. According to petrophysical data of channel sand tested in the laboratory, the influence of pore fluid and lithology on petrophysical elastic parameters were analyzed. Based on elastic impedance equation, the author obtained the sensitive parameters to the reservoir fluid by means of direct inversion of elastic parameters. Pre-stack seismic inversion was used for fluid identification of shallow layer channel sand reservoir in KD area. The results achieved by the authors show that seismic identification accuracy of fluid has been improved, and a good geological effect has been acquired.

Compared with traditional culture-dependent methods, culture-independent techniques based on functional genes for detecting oil and gas indicating microorganisms are more rapid, stable and specific, thereby suitable for commercial applications. In this study, the authors chose Chen 22 wells zone in Shaojia subsag of Zhanhua SAG as a model system. Based on the analyses of the soil samples collected from point, linear and areal surveys, the authors detected that the anomalies of gene abundance were perfectly consistent with the presence of the oil and gas reservoirs. Therefore, microbial molecular prospecting technique for oil and gas is very promising in the future.

Conventional parabolic radon transform method cannot attenuate the multiples ideally and causes spatial alias for the short spread and sparse sampling seismic data. After analyzing the papers by Sacchi, Mauricio, Todd Mojesky and some other researchers. on multiples attenuation by using parabolic radon transform method, this paper describes the theory of high resolution parabolic radon transform method. The result shows that the high resolution parabolic radon transform method can efficiently and effectively realize spatial anti-alias multiples suppression after the new method is applied to the model data and real seismic data respectively; meanwhile, this method can overcome the limitation of insufficient samples and short offset.

Wavelet estimation is the foundation of high-resolution seismic data processing and interpretation. It is of great significance to estimate the wavelet rapidly and exactly. This paper gets the amplitude spectrum from the trispetrum and phase from the seismic data based on the principle of kurtosis maximum, which avoids phase wrapping properly, and discusses the application condition of this principle. The property of the different window functions is also compared, and Hamming is moved to calculate the time-varying wavelets. The ricker wavlet model is used which is frequency-changing to illustrate its effectiveness. In the real data processing, the method is comparatively analyzed for the well-seismic calibrated data based on different frequency ricker wavlets. The results show that the estimated wavlet amplitude spectrum is more stable, and the phase spectrum can be realized easily and is more consistent with the true wavelet.

One of the most important steps of surface-related multiple elimination (SRME) is subtraction of the matching multiple waves from the original data. The L2-norm adaptive multiple subtraction method applies to the situation in which the energy of primary wave is very low; however, the L1-norm adaptive multiple subtraction method could apply to the situation in which the energy of primary wave is strong. To obtain a more ideal method, the authors built a mathematical model to combine L2-norm and L1-norm adaptive multiple subtraction method by means of weighted array, and proposed the method for determination of weight coefficient. In addition, the method which combines synthetic data with field data was illustrated, and the results between using the hybrid L1/L2-norm and using L2-norm and L1-norm alone were comparatively studied. The results show that using the hybridL1 /L2-norm adaptive multiple subtraction method can not only suppress the multiple wave better, but also keep the primary wave well.

The electromagnetic noise sources in the Dongguanshan ore district were investigated in this paper, and the five-component electromagnetic field was measured along the test profile with spectrum analyzer. According to test results, the electromagnetic noise is mainly composed of 50 Hz and its odd harmonics, and the even harmonics is also strong at some sites; the harmonic number of noise is related to the intensity of noise; not only the electromagnetic noise characteristics are different from each other at different sites, but also the noise characteristics of each component are different. Except for the regular noise, there exists ambient broad banded noise, which occurs at all the frequency band, with stable amplitude. The result of long time noise measurement shows that there is not any weak-noise time interval in this ore district.

The spectrum parameters of Cole-Cole model can be used to distinguish the polarization bodies and explore deep ore deposits based on induced polarization anomalies.Due to the low efficiency in field work, this technique has not been widely used in exploration. Current time-domain IP instrument can observe the apparent chargeability data which can reflect the attenuation of secondary polarization potential in multiple time intervals. According to the theory that SIP and TDIP can be transformed mutually, in this paper the authors presented a method for extracting the Cole-Cole model parameters from TDIP data, which achieved good prospecting results while applying to the field geological exploration work.

WSJ-4 pseudo-random signal multifunction digital IP instrument receiver system is based on the Chinese Academy of Engineering, Central South University Professor He Jishan invention a frequency domain induced polarization theory of a new generation of geophysical equipment. As the same series dual-band instrument in the Geophysical sweep surface application to play a lot of advantages, but it is not a good solution to the distinction between the carbonaceous rocks and ore Therefore, the device is in this case, based on the academician He 2ⁿ pseudo-random signal power law theory developed, mainly carbonaceous rocks and ore phase of different frequency response relationship different to be distinguished from each other. Engineering practice shows, the WSJ-4 excited electric meter receiving system can distinguish between carbonaceous rocks with mine. As the first R&D personnel, the article introduces the basic principle and method of the WSJ-4 multi-functional digital pseudo-random signal receiving system, as well as in the practice of laboratory test data and engineering application examples, informative illustration of the instrument the Features and application effect.

The substantial microseismic monitoring data bring many difficulties to the long distance wireless real-time transmission of data and,what is more,take up a lot of disk space.In this paper,using adaptive threshold STA/LTA algorithm,the authors select appropriate characteristic function and automatically,quickly and accurately identify effective micro-seismic signal from the large quantities of monitoring data.Then,the method on the paper accurately determines the start and end time of the effective micro-seismic signal complete waveform,and removes large quantities of redundant data by completely intercepting valid signal,so that the original data are reduced to 20%.Finally,the monitoring data compression ratio attains 10:1 by using STEIM2 algorithm compress data intercepted.

Under the condition of airborne gravity drape flying, the authors employed the GT-1A airborne gravity system to explore whether changes in aircraft attitude could affect the airborne gravity data and to test the possibility of applying the slight slope drape flying to gravity survey. The authors collected data from the same line with two kinds of rate of climb ( 1m/s and 2m/s), and the results showed that there were no significant differences in the airborne gravity data between these two drape flying conditions. The findings imply that the GT-1A airborne gravity system could be applied to airborne gravity survey with drape flying.

The improvement of the low SNR seismic data imaging quality for marine carbonate target has become the main task in seismic processing work. The problems concerning seismic image processing were summarized after the analysis of the seismic geological conditions and the characteristics of the original data, the study of the targeted processing flow and the performance of the work of test process treatment. On such a basis, the authors established an efficient process consisting of pre-stack comprehensive multi-domain noise suppression, multiples combined attenuation, large offsets anisotropic NMO processing, and anisotropic pre-stack time migration. The results of practical data processing show that the imaging precision of sections are improved greatly, the reflection characteristics of various geological phenomenon can be identified clearly, and the accuracy of data interpretation can be effectively improved.

Techniques of prestack fracture prediction mainly aim at vertical and high angle fractures. However, low angle fractures of the tight sandstone gas reservoir are dominant in Chuanxi field of Xinchang survey. Therefore prestack methods are not suitable to this survey. Furthermore, the reliability of single poststack attribute to predict fractures has been questioned. To overcome the above problems, the authors propose in this paper a new idea about the integrated fracture prediction. Firstly, fracture classification based on multi-attribute is adopted, and real measured data are used to monitor the result, and then qualitatively integrated fracture prediction of multi-attribute and multi-scale is realized. Secondly, ant attribute body can be obtained from curvature that has filtered the background data. The influences of the background part of curvature on the ant attribute body can be reduced, so that ant attribute body with high precision is obtained, which can recognize smaller fractures clearly. Finally, on the basis of the ant attribute body with high precision, 3D fracture model is established, and then quantitative prediction on the features of fracture development can be realized. The application of this new idea of integrated fracture prediction to Xinchang survey shows that the new method is effective, and the problem of low angle fractures prediction is effectively solved.

Some inversion errors may be caused either by the distortion effect of the localized conductivity heterogeneity or by the fact that line direction is not perpendicular to the structural strike in the AMT measurement. This study took Northern Guangxi area as the study area: The best orientation of principal axis was found by choosing suitable method to carry out the impedance tensor decomposition. The limited data were used to extract such information as one-dimensional and two-dimensional skew, and the dimensional characteristics of electrical structure were analyzed. Finally, the best orientation of principal axis was applied to the 2-D inversion, thus the resistivity inversion section that conforms to the actual geological conditions can be obtained. Drilling verification has demonstrated the effectiveness of this method, which can analyze the dimension characteristics of geo-electric structure better and identify hidden structures.

With the effect of high-voltage line on CSAMT data in a prospecting area as an example, the authors tried to find the methods of data processing on the basis of the characteristics of electromagnetic interference. This paper summarizes the characteristics of the effects of high voltage line on CSAMT data in the prospecting area. The authors recovered magnetic signal close to the normal field using interpolation method, then calculated the apparent resistivity using the original electric signal and recovered magnetic signal. Comparative studies and drilling verification demonstrate that this method is pretty good and could be used in data processing under similar conditions.

The problems as to how to suppress various kinds of disturbance efficiently, raise signal-to-noise ratio and guarantee the data quality have become the key issues in the collection and handling of MT data. To get more accurate results, the authors introduced the EMTF system (single, reference and MMT) and used this system to process some of the MT data obtained from North China, and also compiled Matlab program so as to rewrite parameters easily. In comparison with SSMT-2000, the EMTF system can suppress the noise in most cases and greatly improve the efficiency of data processing.

Coordinate data, as the basis of the data involved in the whole process of airborne geophysical data processing, are closely related to the quality of data processing and interpretation effects. Based on an analysis of the requirements of geophysical data processing and interpretation system and the employment of C++ language, in combination with the coordinate parameter file management mode, the authors provided the standardized API interface, developed the function of coordinate transformation, and evaluated the conversion accuracy. The results have achieved the requirement of airborne geophysical data processing.

There is an important advantage in foreign outstanding integrated geophysical data processing and interpretation software, which provide a powerful, simple and intuitive, interactive data management module for user. After comparatively analyzing data management module's features of some outstanding software such as Winglink, Emigma, Geosoft, from anatomy to generic, this paper put forward a technology solution to quickly build 2D visual integrated geophysical information management module based on open source GIS platform, and elaborated on the technical principles of its related functions and implementation process. Practical application results show that this technology solution is feasible, and also have advantages such as low cost, high efficiency and strong openness.

In Jindong-Liuqiao area on the southern slope of Dongying Depression, large-area false anomalies emerge from geochemical signals because of strong interference caused by complicated surface conditions. The types of the surface interference were recognized firstly in this area. On such a basis, the geochemical signal was analyzed with Mallat wavelet and the scale 3 continuous sequence reflecting the surface interference was detected and eliminated. The micro-seepage and seepage anomalies for geochemical hydrocarbon exploration of this area were obtained on the basis of the correction of sealing conditions. The anomalies are consistent with faults, traps and hydrocarbon reservoirs already found or the hydrocarbon shows after the interference elimination, which suggests that these anomalies mainly reflect the underground hydrocarbon reservoir information.

The regional data of Cd in surface and deep layer of soils in Weihai were collected to investigate the geochemical characteristics of heavy metal Cd based on regional geological background. The results suggest that the background and baseline values are 0.090×10^-6 and 0.056×10^-6, respectively. The regional soil environment quality of Cd element is generally good, only 3.42% of the region's surface soils and 1.17% of the deep soils exceeds the Ⅰ grade of National Environmental Quality Standards in Soils of China, and only 1.67% of the surface soils exceeds the Ⅱ grade of National Environmental Quality Standards in Soils of China due to contamination. The input of Cd in soils of the study area could be mainly classified into natural and anthropogenic sources. The natural sources dominated area of Cd accounts for 54.68%, in which a good correlation of Cd between the surface and deep soils and geochemical element combination characteristics of Cd with other heavy metals in surface soils could be detected; the distribution of Cd content in surface soils of natural area is mainly affected by the parent materials, the Mesozoic intermediate-acidic intrusive rocks control the distribution of Cd in soils of hilly areas, and the Quaternary sediments control Cd of soils in plain areas. In addition, the terrigenous sediment-dominated plains' surface soils have relatively higher level of Cd content, whereas the plain related to seawater generally has a lower Cd content. However, the anthropogenic sources-dominated area accounts for 45.32%, in which the natural properties of Cd in soils have been destroyed because of artificial interference, and the increasing of Cd content in surface soils could be attributed to human activities such as factories and mining activity.

Acoustic test method and process are discussed in this paper. Through the speed of propagation of acoustic wave in rock mass, the authors established the mathematical model for the thickness of cracking rock mass and the degree of degradation. The results show that, where the thickness of cracking rock mass is less than 30 mm, the strength loss is relatively big; where the thickness of cracking rock mass is greater than 30mm, the strength is essentially unchanged. These data provide reliable scientific theoretical basis for the protection of Huashan rock paintings in the future.

Karst detection is one of the important detection tasks in subway construction. Signal propagating characteristics of ground penetrating radar in the cave and in the rock show significant differences. The amplitude, wavelength and frequency of the radar wave change with the electrical properties of the media, and hence correct identification of radar wave group characteristics of karst cave is the key to identifying caves and their properties. This paper deals with the implication of karst detection in Nanjing Metro Line between the Binjiang Road Station and Wutang Village Road Station,with emphasis placed on the waveform display characteristics of the karst cave on the ground-penetrating radar detection. In combination with drilling verification,the authors hold that the ground penetrating radar is effective in detecting the karst in the city subway tunnel.