Alkalescent granites and gold-related silication and argillation are geological prerequisites for the formation of noticeable gold deposits. Al, K and Sn are indicator elements for ore prospecting work in the Heicigou gold orefield and reflect rather objectively main ore prospect areas in the region. Nevertheless, such an element association is only suitable for arid and desert areas and high and cold mountain areas mainly characterized by mechanic weathering and transportation where coarse-grained stream sediment samples are collected.

South Beijing area is covered with Cenozoic sediments, so underground geological structures are unclear. Through a synthetic analysis of numerous geophysical data and consulting available geological and borehole data, the authors inferred various fractures, computed the depth of the pre-Cenozoic bedrock surface, defined the main geophysical-geological boundaries and lithological formations, discussed the division of tectonic elements, got a clear understanding of geological structures and put forward some new opinions. The results obtained will grow an important role in geological structural studies of Beijing area and are hence of great significance in Beijing's economic development.

Based on the fundamental data of geochemical secondary halos in Wolongquan area, southern Liaoning Province, this paper discusses the application of factor analysis to the optimization of anomaly targets of geochemical secondary halos.

Liupanshan basin is a high abundance and uniform-nonuniform geochemical field in the main oil and gas basins of China, and its background tends to change from high to low from southeast (Guyuan depression) to northwest (Haiyuan depression). According to the variation characteristics of the geochemical background in this basin, the authors determined the techniques for data processing and anomaly appraisal. On the basis of index analysis, the effective geochemical index association was decided, new anomaly-extracting techniques were adopted, and the structural anomalies and composite anomalies were studied. It is found that geochemical anomalies show zoning and obvious oil-indicating characteristics.

Based on geological data and physical property data as well as processing of gravity and air-borne magnetic data, the authors, constrained by some geological information, has conducted the gravity and magnetic man-machine forward modeling in the Alongshan area. The purpose of the study is to formulate the models of underground geological bodies. The results obtained clearly show the distribution characteristics of the underground geological bodies. On such a basis, underground lithologic characteristics and structural distribution regularity can be inferred, which can serve as reference materials for regional geological mapping.

Several special physical models were analyzed and discussed by using the contrastive method in this paper. When some electrodes are lost, the most remarkable change of the resistivity is in the underneath direction, and the anomaly configuration is mostly changed in the horizontal direction because of the location and the number of the lost electrodes.

Based on a study of the log interpretation methods for the physical parameters of effective porosity, permeability and initial oil saturation as well as the construction of the log interpretation model, this paper gives the log interpretation standard for effective porosity and permeability. The initial oil saturation calculation method and the log interpretation standard are also discussed. The results provide geological basis for the further development of Saling Formation oil reservoir.

Controlled by a cataclasite zone, the Yinkengshan ore spot has undergone hydromicatization and metallic sulfide mineralization. There exists electric difference between the orebody and the wall rock. The application of dual frequency IP method to detecting uranium mineralization information at the depth has yielded satisfactory results. The three ore-bearing cataclasite zones exposed at surface are found to extend to some extent in the direction of dip, suggesting that there are some uranium (molybdenum) potentials at the depth.

Based on characteristics of air-borne gamma-ray spectrometer survey, the authors induced the 2-D terrain correction formula, and accomplished the forward calculation. The result of practical data processing indicates that the terrain correction has been remarkably improved.

In the exploration of water sources as well as water supply pipes and wells, the author established the regression curve and calculated the mineralization degree of the formation water on the basis of the correlation between the amplitude values of the electric logging curve over the equifer and the degree of mineralization. The results provided reliable data for well designing and thus played a key role in well construction.

The signal-to-noise ratios of seismic data acquired in Yiyang complex mountain area are low and the amount of static correction is large. In accordance with the data characteristics, the following data processing techniques were used: For the purpose of solving the problem of static correction in the data processing, the uniform datum level for the whole area and the refraction static technique were adopted. Various means were employed such as pre-stack noise elimination, target velocity analysis, DM0, optimizing iteration and stacking, F-X domain signal enhancement, optimizing processing flow and careful selection of processing parameters. As a result, satisfactory outcomes have been obtained.

In this paper, the magnetic exploration technology is applied to the geomagnetic anomaly analysis of hollow ferroconcrete cylinders. By using the method of volume integral, the analytic equations of various components of the geomagnetic anomaly are formulated. And then the central section, the planar isogram and the three-dimensional map of the geomagnetic anomaly vertical component Za are drawn. Furthermore, the distribution features of the magnetic anomaly are detected. In addition, this paper has analyzed inversion problems on the height and the site of hollow ferroconcrete cylinder, and studied the relationship between the altitude of magnetic survey and the magnetic anomaly. The results are theoretically and practically useful in archaeology, engineering exploration and such military fields as the reconnaissance and anti-reconnaissance of this type of objects.

Surface model tomographic inversion is a kind of nonlinear model inversion technique. Using traveltime and path of seismic initial wave to inverse the velocity structure of media, it is not constrained by longitudinal and transverse variations of surface and near-surface structures. On the basis of the error caused by the difference between forward initial time and practical initial time, the velocity model is revised and, through repeated iteration, the error precision required can be attained. In working out static correction, the beam method is adopted to calculate the traveltime between the shot spot and the detection spot. In this way, the datum level correction quantity can be obtained.

The general acoustic inversion method is based on layer media. As the water-eroded cave type carbonate reservoirs are characterized by high heterogeneity, the general acoustic inversion has its shortage. The utilization of the multi-constrained sparse spike inversion can identify the water-eroded cave type carbonate reservoirs and obtain accurate 3D wave impedance data. Different wave impedance data based on the low velocity character of water-eroded cave type reservoirs can be extracted. The technique is reliable for water-eroded cave type reservoir prediction in geological exploration.

This paper has described the C/O spectral logging technique and analyzed the factors affecting this technique. With practical example, the paper deals emphatically with the application of this technique in the oil fields.

MAPGIS software of the Geographic Information System has been widely applied to the geological field. This paper briefly describes the structure and function of ASCⅡ code conversion system software of MAPGIS based on ASCⅡ code files of MAPGIS and the application of this software to geophysical and geochemical fields.

The construction of the oil and gas geochemical database is the basis of resource sharing, scientific management and macroscopic decision-making of oil and gas geochemical information, and also serves as the foundation of oil and gas geochemical data processing and anomaly appraisal. Having collected and recorded oil and gas geochemical data of the past tens of years, this system can accomplish the registration, management, browsing, retrieval, report forming and preprocessing of oil and gas geochemical data. This paper has described the structure, characteristics and functions of the oil and gas geochemical database, and dealt further with the quantification and computerization of oil and gas geochemical exploration. All this represents the new advances and new research level in the field of oil and gas geochemical database.

According to the sampling points which have or have not coordinates of geographic localities, this paper has divided the process of establishing geochemical graphics-database into two conditions: the condition that the general geochemical database has been established and that the general geochemical database has not been established. With the condition that the general geochemical database has not been established as an example, this paper not only describes the idea, process and methods for establishing geochemical graphics-database, but also discusses the method of retrieving and drawing geochemical thematic maps with MAPGIS software based on the established geochemical graphics-database.

To solve the problem of excessively big file, the authors studied the file format of SIR ground prospecting radar. A practical method was designed to read and cut the big radar image by means of Matlab programme. The efficiency of using GPR testing tunnel will be improved in field work.

In the light of soil magnetism, this paper deals tentatively with the problem of raising utilizartion ratio of chemical fertilizer, one of the forefront subjects in agricultural production. 125 groups of data concerning soil magnetism, nutrient elements N, P, K and organic carbon were collected from Pinghu area of Hangzhou-Giaxing-Huzhou plain and are distributed in 36 depth profiles within 560 km². An analysis of the variation of these data with depths reveals that soil magnetism of the non-plough layer has a relatively good correlation with K, N and P but shows a rather poor correlation with organic carbon, suggesting that minerals responsible for soil magnetism have the capability of keeping nutrient elements. Soil magnetism of the plough layer is in relatively good correlation with organic carbon and P but shows a rather poor correlation with N and K. Soil magnetism, N, P and organic carbon are higher in the plough layer than in the non-plough layer, whereas things are just the opposite for K. From the non-plough layer to the plough layer, the increase of soil magnetism is 23.8%, much lower than the increase of N (55.3%) and P (36.6%) and the decreasing range of K (95.8%). This indicates that there exists disproportion in the application of chemical fertilizer in this area, which leads to the unbalance between soil magnetism and content of nutrient elements. Applying more magnetic fertilizer seems to be one of the ways for raising the effectiveness and persistence of the fertilizer.

Based on systematic sampling and investigation of the deep layer of soil (No.I environment), the authors worked out the serial reference geochemical values of the elements in soil of Chengdu City and found out their basic characteristics. The values include the element reference values of soil in the whole area and in different scenic spots, different soil types, different lands and different administrative districts. The data obtained provide practical and basic geochemical information for regional economic planning as well as resource and environmental evaluation.

In the construction of Ningbo Bridge, Zhaobaoshan highway tunnels were designed as twin tunnels with large span and excessively small interval of 4 m, only 1/7-1/10 of ordinance in the norm. A series of measures should be adopted for the safety of tunnels. One of the crucial measures is the protection of the rock mass between the two tunnels, which includes the utilization of controlled blast to protect rock mass. The author used such techniques as sonic wave measurement, Landsonar method and vibration velocity measurement to measure the depth and condition of rock mass under blasting. In addition, the displacement, the strain and the pressure of the tunnels and the shotcreting or the lining were also measured to inspect the safety of the tunnels. With the help of the measuring data, the construction plan, construction procedures and blasting parameters were determined. The engineering is successful and the economic benefits are obvious.

Using the synchronous monitoring analysis of tamper vibration, we can obtain seismic intensity evaluation affected by tamper vibration, basic frequency and maximum velocity parameters. With a practical example of tamper vibration monitoring, this paper has analyzed the vibration monitoring result and the contents of practical application.

The stability of the strata of a coal mine is seriously affected by the underlying worked-out area, which frequently causes deformation or even collapse, depression and geofracturing and hence gravely threatens the buildings above it. For the purpose of consolidating the rock and soil bed, drill-hole grouting has often be used to plug the worked-out area and fractures of the rock and soil bed. In this paper, the principle of applying ultrasonic wave method to detecting drill-hole grouting quality is described and the test result is analyzed.