In the work of exploration geophysics from 1999 to 2001, regional geochemical exploration was carried forward in western China, with resource investigation and evaluation occupying the leading position, while multi-purpose regional geochemical mapping was started in eastern China, with emphasis placed on environmental investigation and evaluation. As a result, a series of important advances and achievements were made, and the development pattern of exploration geochemistry in the new era which lays equal stress on resources and environment was gradually formed. To suit this pattern, this paper puts forward a kind of basic thinking and method in which geochemical evaluation of potential resources and geochemical appraisal of ecological environment play the leading role.

In the light of abundance features, geochemical characteristics and correlations of newly added analytical elements in surface, depth and granularity tests of multitarget geochemical survey in Chengdu plain as well as their content in soil, this paper deals with geochemical characteristics of these elements. C, Se, S, N and Cl are concentrated in shallow layers, whereas Sc, Tl, Ge, I, Cs, Ta, Hf and REE, especially HREE, are concentrated in deep layers.

Gas hydrate has been called the new energy resource of the 21th century with the gradual exhaustion of petroleum and gas in the world. The researches on gas hydrates have recently become a major focus both at home and abroad. As a traditional evaluation method for oil/gas reservoir, geophysical well logging remains one of the effective means in gas hydrates reservoir evaluation. This paper has made a preliminary description and analysis of the response characteristics of geophysical well logging.

According to the newly-obtained 1:100 000 high precision aeromagnetic data of Luoping Wenshan area in Yunnan Province, this paper made a comparative study on characteristics of ringed magnetic fields caused by known intermediate and acid intrusive bodies and, on such a basis, found that some magnetic anomalies are quite similar to known intermediate and acid intrusive bodies in shape. Combined with physical characters and geological, gravity and geochemical data, it is held that these ringed magnetic anomalies mainly reflect concealed intermediate and acid intrusive bodies. As is well known, intermediate and acid intrusive bodies are closely related to silver, copper, lead and zinc polymetallic ore resources. Therefore, such magnetic anomalies seem to be favorable places in search for these resources.

The intellectualized detection technology is important in the seafloor magnetotelluric acquisition. The key problems encountered during the signal acquisition are large quantities of detection information, long working time on the seafloor, serious disturbance of the environment and complex logical control. These problems could not be solved without intellectualized measures. In fact the procedure of intellectualizing the seafloor magnetotelluric acquisition is the procedure of applying the computer technology to the acquisition autocontrol, automatically saving the data with the circuit having immunity. Considering the specific characteristics of the operation in the ocean engineering, the PC104 is inset in the seafloor magnetotelluric instrument as a control unit. Several control interfaces are selected and the controlled positions are arranged correctly. The circuit driver takes into account the compatibility of various interfaces. The instrument has been proved to be effective and practicable through the marine experiments.

In the light of the pulse width of the radar wave, this paper deals with the difference and the relationship between the vertical resolution and the transverse resolution of the ground-penetrating radar, indicates the influence of the noise upon the resolution and, with practical examples, points out that the digital handling of the signal can greatly improve the resolution of the radar.

In middle and high mountain areas, the landform is complex, the flying altitude should be relatively high, and the intensity of magnetic anomalies detected by aeromagnetic survey is hence relatively weak. In order to utilize the magnetic anomaly information obtained by high-precision aeromagnetic survey more effectively, this paper, based on the reliable proof of the existence of weak magnetic anomalies in middle and high mountain areas and combined with characteristics of middle and high mountain areas, has advanced an improved nonlinear filtering method and described its effect in practical application.

Physical model experiment is a basic study in electromagnetic log response and its forward and inversion calculation. In combination with experimental studies, this paper presents the research on electromagnetic logging in an oil and water layer model which is identical in geological condition with the multi-frequency electromagnetic logging. In addition, a set of experimental methods and measuring techniques are summed up. This paper also makes an analysis and discussion on the curve measured from the experiment. The result of the experiment is fairly good.

This paper has summed up the experience acquired in the correction of traditional errors in applying "8"shaped observational technique of the spontaneous electric method to measuring the flow direction of groundwater, and discussed such aspects of the initial range as reasons for its generation, degree of its influence and the tackling technique. The compensation method in late stage dataprocessing is also dealt with in this paper.

The application of seismic method to mineral exploration is a very difficult problem. As the seismic geological conditions involved in base metal ore deposits are very complex, conventional seismic reflection techniques applied to layer media are subject to challenge. The prospecting for deep concealed metallic ore deposits by using scattering event method is a bold attempt. This paper tries to discuss the effectiveness of this method in the light of data acquisition and processing as well as comprehensive interpretation combined with the seismic experimental work conducted in the Ciajiaying polymetallic deposit of Hebei Province.

The AVO technique is mainly used to study the variation regularity of seismic wave amplitude with the migration distance, and the distribution of the 3D seismic data directly influences the effects of AVO processing. The designing and utilizing of old 3D data failed to consider the special requirements of AVO technique, which caused some degrees of distortion in AVO attribute. Aimed at solving this problem, this paper has analyzed the requirements of AVO for the designing of the 3D observational system and put forward an AVO observational system, which can not only suit the traditional 3D exploration but also meet the specific needs of the AVO technique.

GPS satellite positioning is a new surveying technique in geophysical exploration. This paper deals with the integration of GPS techniques, which includes the technical performance of OEM plate and the interfaces of the software and the hardware in GPS. Based on analyzing the sources of GPS positioning, the paper puts forward a simple GPS difference technique.

This paper deals with the analytical mechanism of thermally-released hydrocarbon and the influence of topography, land form, horizon and sample character upon the analytical result of thermally released hydrocarbon. On the basis of test, the optimum analytical conditions for thermally-released hydrocarbon has been determined.

The Tongbai Xinyang regional geochemical survey is a component part of the nationwide regional geochemical survey. The map compilation involves the collage of No.19 zone and No.20 zone as well as four 1:200000 map sheets, and hence there exist quite a few difficult technical problems in map making. In order to avoid the fissure coordinate inconsistency between the two projection zones, the authors converted the data of No.20 zone to No.10 zone, looked up the natural coordinate values in the Gauss-Kruger coordinate table, and calculated the general coordinate values. On such a basis, the coordinate plotting was performed. The map making result seems quite satisfactory.

In the present study, 3-D high resolution S wave velocity tomography by 1°×1° cells have been performed within the limits of crust and upper mantle from by using surface wave dispersion inversions,through collecting 1500 three components long-period digital seismic records from 187 representative events recorded by 44 seismic network stations which over Asia, part Europe and the west Pacific Ocean areas from 1986 to 2001, picking out 390 accurate surface wave dispersion cures which great circle path nearly cover Tibetan plateau. According to the tomography rsults about S wave velocity, crust thickness of Tibetan plateau has been detected. This paper discusses the structure evolution and dynamics feature of Tibetan plateau.

This paper has summed up the application of GPR to the detection of pavement thickness and highway structures, analyzed the physical prerequisites of GPR in thickness and structure detection, and compared this technique with the drilling borehole method. Based on practices, the authors point out the prospects of GPR in non destructive detection of highway engineering.