The Yangtizishan diagenetic-metamorphic titanium deposit in Inner Mongolia is of a new type. Based on the study of geological and geophysical prerequisite and the test of ore-prospecting methods, the authors hold that the high-precision magnetic method is the basic method in search for the diagenetic-metamorphic titanium deposit, and gravity survey is an effective ore-prospecting method. Over the Moshishan rutile-dominant titanium-rich ore body in the northern belt of the ore district there is a gravity anomaly of 600 μGal with no magnetic anomaly, whereas over the Yangtizishan titanium ore body in the southern belt there occurs a gravity anomaly of 500 μGal together with a weak magnetic anomaly of 60 nT.

Based on the regional geological background of the South Yellow Sea Basin and the North Yellow Sea Basin, this paper describes the location and stratigraphic attribute of Line HHQY05-1 that stretches across the two basins. The authors comparatively analyzed velocity spectra, average velocity and interval velocity of the two basins, and reached the conclusion that the seismic velocities of them are quite different, and the average seismic velocity of the South Yellow Sea Basin was lower than that of the North Yellow Sea Basin, which is attributed to the differences in their geological structures, lithologic characters and geochronologic units. Therefore, the tectonic characteristics and geological attributes of the basin can be roughly detected by using the seismic velocity.

According to geochemical anomalies in combination with characteristics of geophysics, geology, mineral resources and products revealed during the eco-geological investigation along the Yangtze River Economic Belt of Chongqing, the authors hold that their exists a nearly NS-trending concealed fault belt in Wanzhou and an EW-trending concealed fault belt in Fuling. The new understanding that there exist two important basement structures is of great importance in basic geological researches of this area.

This paper has expounded characteristics of element distribution and regional geological setting in Zhenan (in Yuntu)-Luoyang (in Yangchun) area,and pointed out that Au, Ag, Cu, Pb, Zn are major ore-forming elements,and that the prospecting for altered fault rock type gold deposits,volcanogenic gold deposits and magmatic hydrothermal silver-polymetallic deposits is very promising in this area, with faults and alterations making up the main ore-hunting indicators.

The caldera in Qingyuan County has the Xiantaoshan volcanic body as its center, and the anomalies of high, middle and low-temperature ore-forming elements are distributed in succession from the interior part outwards. These anomalies are different from each other in such aspects as spatial distribution, mineral composition, structure and texture, wall rock alteration and associated minerals. A detailed discussion on spatial distribution characteristics of the caldera by combining geophysics and geochemistry can help us broaden the train of thought in search for different mineral resources and appraisal of prospective mineral resources.

Geochemical Pt and Pd exploration led to the discovery of two precious metal anomalous concentrations in the Gaositai ultramafic complex, Hebei Province. Anomaly concentrations of Pt and Pd in rock, soil and stream sediments overlying the dunite and peridotite zone of the Gaositai complex coincide with the well-known PGE-bearing chromititc mineralization. These platinum anomalies are also associated with strong anomalies of such elements as Cr, Co and Ni. Nevertheless, Pd assumes very low background distribution, whereas the w(Pt)/w(Pd) ratio is higher. The second type of elevated PGE anomalous concentration follows the strike of the diopside zone and the shearing fault zone of the Gaositai ultramafic complex. These anomalies are characterized by strong anomaly intensity with a close relationship existent between Pt and Pd and the w(Pt)/w(Pd) ratio close to 1. However, no strong anomalies of Cr, Co and Ni are observed. Such a phenomenon is therefore thought to be the reflection of a new PGE mineralization. It is thus held that hidden PGE mineralization difficult to be recognized may be discovered by means of Pt and Pd geochemical exploration using rock, soil and stream sediment samples.

The Shanggong gold deposit lies on the northern slope of the Xiong'er Mountain in western Henan. In an area of 1 020 km², 1:50 000 geochemical stream sediment survey was conducted. The sampling units were divided according to the drainage system. The sampling was carried out in accord with the principle "dense sampling in small ditches, relatively sparse sampling in tributaries, and no sampling in main rivers". This stream sediment survey was characterized by less sampling, large controlled area, rapidness, reduction in cost, manpower and material resources, and good ore-prospecting and economic results. Gold anomalies were detected in this stream sediment survey, and subsequent anomaly inspection, geological evaluation and drilling verification led to the discovery of a large-sized tectonic altered rock type gold deposit.

Based on two times of regional geochemical prospecting work in Iran, this paper has made a comparative analysis of such problems as the density of sampling points, the composite samples and the map-compiling methods in accord with the basic principles of stream sediment survey.

Based on the ray tracing theory, the authors put forward an improved trial firing path tracing algorithm, which can simulate the propagation of rays in layered media quite accurately. This algorithm can not only figure out the journey time and the ray paths of all reflection waves received by any detection point but also has the merits of rapidness, accuracy and adaptability to complex structural models. With the conjugate gradient method and through altered iteration of the forward model, the authors studied the inverse algorithm of the microearthquate layered model. Finally, inversion of practical test data was performed, and the result is basically consistent with the real data.

In view of such phenomena as complex surface conditions, shallow target formation depths and overlying Gobi and hills encountered by 3D seismic exploration in a certain coal mine of Tacheng area, Xinjiang, this paper deals with some corresponding technical measures and their geological effects at different stages of field data collection, data processing and data interpretation. Exploration results indicate that seismic geological results with relatively high exploration precision can be obtained under complex surface conditions in Gobi area by using such techniques as small CDP grid, high covering numbers, in situ monitoring and control, fine processing, man-computer interaction supplementary interpretation system and multivariate geological information analysis.

In view of the peculiar physical and chemical properties of CO₂ gas accumulation, the author holds that only by integrated application of various data and techniques can CO₂ accumulation be effectively recognized. Regional geological analysis and geophysical-geochemical exploration methods should be utilized in an integrated way to evaluate the distribution of non-hydrocarbon gas and then locate objectives for drilling. Non-hydrocarbon chromatographic measurement and infrared CO₂ concentration measurement ought to be performed to realize in-situ drilling dynamic detection of the CO₂ layer. Gas chromatography is used to test related log parameter data and neutron porosity differential values of nuclear logging density so as to make an integrated interpretation of the CO₂ gas layer and recognize CO₂ gas effectively. New key techniques for integrated exploration of CO₂, such as geochemical method and log, are discussed in detail in this paper.

In the light of the electrical characteristics of groundwater circulation information and on the basis of analyzing the spatial structure within the depth of 450 m in Yinchuan plain, the authors studied comprehensively the spatial distribution of groundwater quality by means of electrical resistivity sounding for the purpose of sustainable utilization of groundwater resources.

The existence of underground mined-out areas poses a grave threat to mine production and engineering construction, and hence the survey of mined-out area has become an important subject. Based on the engineering projects the authors had taken part in, this paper described in detail three techniques (crosswell seismism, ground penetrating radar GRP) and shallow seismic reflection method) for detecting underground mined-out areas and analyzed their advantages and disadvantages.

Using the pyrogenation chromatogram data of the sandstone-type uranium deposit in Yili Basin, the author calculated eight important indices such as hydrogen exponent and oxygen exponent. On such a basis, hydrogen exponent and oxygen exponent were used to divide the types of the kerogen in Yili Basin and evaluate tentatively the mature degree of kerogen in the uranium deposit of this basin.

Three Thiobacillus ferrooxidans strains with strong arsenic resistance and capacity of sulfide ore decomposition, namely M1s, 1# and Malan, were used for a microbial oxidation and leaching experiment on DBF ore from Shimian County, Sichuan Province. The arsenic content and pH change in the microbial oxidation process and the optimum leaching conditions of gold were studied intensively. The change of the microbial oxidation process with time and the optimum leaching conditions of gold are given in the paper.

In order to acquire high resolution GPR exploration data, we should not only adopt suitable methods to get high resolution data in the open field but also process primitive data with essential methods. The precision of the traditional method for complex trace analysis cannot meet the requirement of the high resolution GPR exploration, especially that of the thin interbeds research. Therefore an improved method for complex trace analysis is proposed in this paper to suit the high resolution GPR data. The traditional instantaneous phase plot is compared with the improved instantaneous phase plot based on exploration data of Shanghai-Nanjing Railway subgrade, and the results demonstrate that the improved method of complex trace analysis is more precise and effective than the traditional one.

The paper describes the principle of measuring horizontal component of VLF electronic field by ungrounded dipole antenna in surface, and analyzes the theory and experimentation.

Composite profile and induced polarization methods were applied synthetically to water searching and, as a result, a fault containing relatively abundant water was found in the working area. Then the authors arranged and conducted drilling and carried out an experiment of water-pumping. It is proved that the quality and quantity of groundwater can satisfy the requirement of the school, and hence the drinking water problem of Dongshan school is solved. The authors thus considered that the integrated application of composite profile and IP methods to water prospecting is effective in the red bed area.

This paper has systematically discussed an easy way to determine observation parameters of navigation-based GPS and, through test and research on absolute position precision and relative position precision, discovered the fact that the observation parameter determination plays a leading role in navigation-based GPS positioning. It is considered that the setting up of correct observation parameters seems to be an important means for precision improvement of navigation-based GPS single point positioning.

Having investigated the design of classical FIR digital filter, the authors put forward a method of FIR filter design based on Chebyshev best uniform approximation which can be used to separate potential anomalies. In an experiment on the theoretical model, the maximum error of regional anomaly separation by low pass filter of Hanning window is 6.266×10^-6 m/s² , the mean square error is 2.115×10^-6 m/s², and the maximum percentage error is 22.2%. The errors are always higher than 10.1% when the computing points are beyond ±9 km. On the contrary, regional and residual anomalies separated by the best uniform approximation theory fit fairly well with the theoretical anomaly, with the curves in fairly good agreement. The maximum error of regional anomaly separation is 3.101×10^-6 m/s² , the mean square error is 0.989×10^-6 m/s² , and the maximum percentage error is 7.76% for several data on the boundary and is lower than 4.1% for the other points. The method was used to separate Bouguer gravity anomalies along the Sunwu-Jiayin profile with satisfactory results obtained. It is proved that the anomaly separation is quite complete.

It is convenient to calculate derivative in wave number space using the inbuilt FFT function in Matlab. This paper describes a matlab algorithm for derivative calculation of 1D gravity and magnetic anomaly in wave number space, gives code of program and deals with some programming skills for precision improvement. Through model test and data analysis, it is found that the precision of the FFT method is much higher than that of the Fourier Series method in vertical derivative calculation. In horizontal derivative calculation, however, the precisions of the two methods are almost the same. During kainite exploration in a certain basin, satisfactory result was obtained in the processing of gravity profile data using this method.

This paper researches the sphere beside a well when performed in ground-well IP, forwarding the underground semi-space electric field with analytical solution, and inversing its depth and distance to well by the secondary field abnormal potential differences. We validate the correctness of these forward and inversion formulas by computer simulation, analyze their physical principle, and give their applicable conditions. This research has a definite significance for quantitative analysis of probing the underground objectives with IP.

Because of the huge computation and limitation of computer resource when modeling the diffuse of the transient field in three dimensional medium, FDTD, the nonuniform grid and time step length will be used to study the whole-space response characteristic of two dimensional square and sheet conductive body, located both in uniform medium, and in the layered medium, with a 3 dimensional magnetic dipole, And the diffused regularity of the transient field in them, the effect of laneway and boundary will be also discussed. The objectives are to provide interpretation guidelines for the TEM anomalies arising from the full-space uniform and layered medium.

In this paper, the problems of static correction and low signal/noise ratio in the complex surface seismic data were analyzed and studied on the basis of large quantities of experiments and analyses. The method in which the datum static correction is combined with the refraction static correction was adopted for effectively solving the problem of field static correction caused by the complex surface and low velocity layer. Such factors as surface wave, low-frequency disturbance and regular linear disturbance resulting in low signal/noise ratio of the seismic data were successfully suppressed. The difference in the wavelet of shots was solved effectively with the surface consistency deconvolution technique.

Based on the principle of the 'mise-a-la-masse' method and the result of model pile testing, this paper deals with electric field characteristics around the reinforcement cage. Tests reveal that the bottom of the reinforcement cage corresponds to the minimum of the electric potential gradient curve and the inflexion of the electric potential curve. A method for reinforcement cage length detection in the core drilling hole is accordingly presented. Practice shows that the method is convenient, practicable and credible.

In this paper, the author describes the principle as well as the data acquisition and processing method of the sonic wave tomographic imagery (sonic wave CT) from the angle of practice. For the purpose of guaranteeing the inversion precision and improving the initial data quality, emphasis is especially placed on prudent selection of seismic sources, record instruments and sensors as well as reasonable choice of acquisition and imaging parameters. With practical examples, this paper also deals with the application of sonic wave CT to foundation pile inspection and pile foundation exploration.

This paper describes the application of eccentric type vibration exciter to steady state Rayleigh wave exploration, the method of in situ work arrangement and the calculation method for frequency dispersion curves, and makes a comparison between the result of the steady state Rayleigh wave exploration and that of the drill hole wave velocity test. The data obtained by these two methods are quite close to each other. With its low exciting frequency and large exciting energy, the eccentric type vibration exciter can yield good result in steady state Rayleigh wave exploration. It can thus be used to replace drill hole sonic wave test in stratigraphic wave velocity test so as to cut down the cost and raise the efficiency of engineering exploration.