Having experienced the tactic development stage and the

strategic development stage, exploration geochemistry has entered into

the allround development stage in the 21st Century. Each development

stage takes shape under its specific historical condition. In this

paper, the author deals in brief with some characteristics of the all

round development stage and some problems that deserve attention at

this development stage.

A series of Earth's lithospheric magnetic field models,

MF1~MF6, produced by Dr. Stefan Maus and his colleagues according to

data from CHAMP, are recommended in this paper. The author made a

visual comparison between the magnetic anomaly map compiled on the

basis of MAGSAT data and that compiled on the basis of CHAMP data (MF6)

collected over China's continent. It is shown that the anomaly that

appears in the map from MAGSAT（e.g., the anomaly in Tarim Basin）

resolves into several smaller anomalies in the map from CHAMP

(MF3,MF4,MF5,MF6) . Therefore, MF3,MF4,MF5,MF6 are more suitable for

mapping smaller geological features.

Carboniferous Benxi Formation is very thick in the depression of Ordovician weathering crust. Such an environment is favorable for the formation of bauxite and hence seems to be a bauxite promising area. With a successful case study of the highdensity resistivity method in a certain mining area，this paper expounds the effectiveness of the highdensity resistivity method in detecting ancient karst basins and indirect prospecting for bauxite deposits.

Using the method of normalized full gradient of gravity anomaly and its phase in the wavenumber domain, this paper studied four typical staircase models, discussed the relationship between the GH field contour and the phase curve, processed the high precision gravity data on the basis of the measurements made along the Danqinghe forestDaotaiqiao section (called DB4 for short) on the periphery of Daqing prospecting area and recognized eight fractures. Through a comparison with the inversion results from the magnetotelluric method, the authors investigated YilanYitong fractures, Mudanjiang fractures and the west edge fracture of Boli Basin, and also summed up the gravity and magnetotelluric data to perform structural division of this section and make geological interpretation. As fractures are closely related to the formation of source depressions and the entrapment of oil and gas, the authors probed into the main fractures in the DB4 section and their characteristics so as to provide the geophysical evidence for locating the promising oil and gas districts on the periphery of Daqing prospecting area.

An analysis of the composition of soil minerals in the Hetao area shows that the main arenaceous components are quartze, feldspar and calcite, whereas the clay minerals are composed of illite, chlorite and kaolinite. The contents of various minerals are different from each other. Quartz and feldspar are relatively high in sandy soils, while clay minerals are comparatively high in clay soils.

The Huangchengshan silver deposit is a mesothermalepithermal ore deposit. The summarization of the oreforming conditions and geochemical characteristics of this kind of silver deposits is of great significance in enriching their research and service field. Based on an analysis of their oreforming background and geochemical anomalies, the authors established their geological-geochemical oreprospecting criteria with the purpose of serving the evaluation of this kind of silver deposits.

 Due to complex surface conditions, the signaltonoise ratio of seismic data is very low in the M Block of Myanmar. Therefore, it is very difficult to carry out such tasks as the horizontal interpretation of the object layer, the fault interpretation and the determination of structural style. Based on an analysis and study of the stress field of the M Block in Myanmar in combination with surface structural characteristics of the profile and reflection features of seismic data and in consideration of the structural style of Kuqa piedmont folded belt in Tarim Basin of China, the authors made an integrated analysis and study of the structural style and seismic data of the M Block in Myanmar under very unfavorable data conditions. As a result, fairly satisfactory result was obtained.

Based on an analysis of the geochemical exploration data obtained in Erzhihala area, some conclusions have been reached: when 1∶50 000 stream sediment survey is conducted in Qilianshan subnival region represented by Erzhihala area, the sample granularity of -40 mesh can yield relatively good result; when the work is carried out in areas over 3 000 m above the sea level, the adoption of -40 mesh in 1∶25000 ditch secondary soil survey is not very reasonable; when the mixed rock fragments and lithic materials whose sizes are smaller than 0.5 cm are collected and the samples are analyzed according to the primary halo method, anomalies can be distinctly delineated. Geochemical outcomes imply that gold mineralized bodies do exist in Erzhihala area, and 1∶10 000 lithic anomalies can basically delineated the limits of mineralized bodies.

Based on data obtained from the Chengmenshan porphyry copper deposit in Jiangxi and the Wunugetushan porphyry copper deposit in Inner Mongolia, the authors investigated the petrochemical indices for the exploration of porphyry copper deposits. It is shown that the contents of such common chemical components as MgO, CaO and Na2O are obviously lower than their abundances in immediateacid rocks, whereas w(Na2O)/w(K2O) and w(CaO)/w( MgO) ratios vary regularly with the increasing Cu mineralization intensity. These results can effectively indicate the existence of porphyry mineralized bodies and their mineralization intensity and greatly enrich the geochemical exploration indices.

Geological work in search for ore deposits is difficult in wide forest and swamp areas of Heilongjiang Province. In this paper，the prospecting work in order of ultra-low and low density (1 site/100 km2)→very low density (1 site/16 km2)→low density (1 site/km2)→high density (18 site/km2) geochemical investigation was carried out according to the strategic thought of rapid control of overall situation and gradual reduction of the prospect area by using the MOMEO method. The results are satisfactory in part of the prospect area, as shown by the discovery of some PbZn ore deposits both in shallow places and in depth. The combination of effective geochemical methods is thus very useful in search for ore deposits in forest and swamp areas.

Based on the introduction of basic principleultra and interpretation methods of low frequency electromagnetic wave.We used the machine made by Beijing University to do some experiments in Xutuan Mine and Pinadingshan No.13 Mine.Then we analysed and ameliorated the interpretation methods according to detection results.

Abstract： In this paper, some major methods for measuring relative dielectric constants of media have been discussed in detail from theory to practice. These methods are applied to GPR (groundpenetrating radar) exploration no matter whether its transmitting antenna and receiving antenna are separated or integrative. Tests show that these methods can meet the requirements in practical work.

In the direct current IP instrument used at present, the terminal time of the power supply square wave of the primary electric field sampling contains the secondary electric field formed by induction. In the high polarizability geological body, the apparent resistivity reflected by the instrument will weaken its low resistivity or enlarge its high resistivity characteristics. In field work, therefore, proper dataprocessing should be conducted so as to reduce such influence.

 In extracting average velocity fields, the choice of different datum planes can lead to different timetodepth conversion results. In the twostep static correction used at present, there are two datum planes to construct the average velocity field and perform the timetodepth conversion: one is the velocity spectrum analyzing datum plane, i.e., the CMP datum plane, and the other is the final seismic datum plane, i.e., the common datum plane. The velocity field and timetodepth conversion were studied on these two different datum planes, and a method was put forward for deriving a smoothed nearsurface plane for timetodepth conversion by averaging all elevations of each receiver and each shot point within the scope of a CMP gathered. A case study shows that this method can provide higher precision velocity field and structure map without using any borehole data than the routine velocity field study method on common datum plane.

As a typical duplex concentration area of oil and gas, the Chengdao oil field has threelayer structure composed of Neogene drape, Paleogene overlap and PreTertiary. In order to analyze attributes of seismic data and work out a method for recognizing the fault system, this paper deals with some relative attributes and two methods for identifying the fault system, i.e., coherence analysis and dip scanning. With the Kendong 30 Kendong 48 area as an example and according to the researches on the relationships between coherence analysis, seismic attribute and fault system as well as the relationships between dip scanning, interlayer attribute extraction and fault system, the authors made application analysis and indicated which attributes can better reflect the fault system. The RAVE attribute visualization was also employed to verify the chosen seismic attributes and recognition method, and the results obtained prove that the recognition methods can identify the fault system quite obviously.

Based on experience obtained in the practical work of the demonstrative projects for China's critical mines, the authors have reached the following conclusions: For the new type JCX3 borehole threecomponent magnetic survey instrument produced by the Chongqing Geological Instrument Factory, when the inclined plane of the probe is directed northward, the positive value of the X numerical reading is the maximum; when the inclined plane is directed southward, the negative value of the X numerical reading is the maximum, and the X component is directed towards the borehole inclination. Although both of the above two situations accord with the left handed rule in the system of rectangular coordinates, the x, y coordinates of the borehole magnetic survey sensor of the new instrument are different from things of the old instrument by 90°. It is therefore thought that, for the measurement results obtained by tens of JCX3 type instruments which are extensively used at present, the utilization of the vector calculation formulae established on the basis of the vertical system might lead to the mistaken application and interpretation. And hence this problem deserves further consideration.

The GPR technology is an important means for detecting and estimating active faults in Changchun. With this technology, the spatial position, burial depth of top brokenpoints and attitude of the fault can be detected. The result of GPR soil layering delamination provides an important basis for accurate and scientific estimation of fault activity.

 Characteristics of toxic elements and nutritive elements for plants in Changshou Wushan sector along the middle reach of the Yangtze River were systematically studied in this paper. Cd and Hg are the most important toxic elements. Compared with the average values of the whole country, the nutritive element abundances have the following characteristics: Corg is over two times higher than and N, B, TFe2O3, Zn and K2O are over one time higher than their respective average values in the earth. The major famous quality and special products are mustard tuber, navel orange of Fengjie and subtropical fruits.

Ecogeochemical features of epidemic fluorosis areas in Guangde Village of Anxi County were studied, and the results show that the F content of rock, soil, drinking water, paddy field and vegetables is relatively high, but Cu, Mo, Ca are gravely deficient. The content of F- is excessive, reaching as high as 4.18 mg/L, whereas the pH value of drinking water is below the standard of drinking water (6.5), and hence it is acidic, and not suitable for drinking. It is held that such an ecogeochemical environment is the main cause for endemic fluorosis.

Based on the conditions of displacement and stress on interfaces and applying the δmatrix method and the dispersion equation in solid multilayered media, the authors deduced the dispersion equation in the existence of fluid multilayered media. A quantitative agreement was reached between the deduced equation and some previous researchers' equations. The modeling results show the correctness and universality of the deduced equation and the integrality of the calculating results. When the multilayered media contain fluids, the dispersion curves assume the zero mode curve which is inexistent in solid multilayered media. The zero mode curves can be regard as a sign of the existence of fluid interlayer in multichannel analysis of surface waves (MASW).

 The essential feature of the seismic wave propagation in viscouselastic media is the attenuation of its energy. Generally speaking, the attenuation can be classified into two categories, one is related to the seismicwave propagation, and the other is related to the characteristics of the strata. One of the most important parameters that scale the degree of attenuation is Qfactor. This paper discusses the stability of spectral analogspectrum ratio method to interference and noise.

Relatively large exploration depth and good resolution at depth are usually required in oilgas and mineral resources exploration. The boreholesurface electrical resistivity tomography technique can satisfy the demand. A typical synthetic geological model was designed in this paper, which is based on the simulation of the finite element method by using Ansys FEM software. The response apparent resistivity of the model acts as the input of the inversion. According to the results obtained by the smoothconstrained least square inversion method, this paper describes characteristics and distribution of the anomalies. The results and the recognition obtained obviously have some practical values.

：The Qiagong iron deposit is a newly discovered deposit, but geometric characteristics of its ore body such as the shape, size, strike, position, attitude and boundary have not been systematically studied. Based on a wavelet and multiscale analysis of theoretical model data and measured data and a comparison of the application results between the upward continuation and the wavelet and multiscale analysis, the authors hold that the wavelet multiscale decomposition of magnetic anomaly can play an important role in search for deepburied mineral deposits.

In this paper local projection and edge detection methods were used for automatic layer separation. First, phase space reconstruction was adopted for log time series, and then noise caused by nonstratigraphic factors was reduced by local projection. Edge projection was utilized to study data of highdegree membership and to detect possible layer boundary according to the loss function. Finally, the model was constructed based on local projection and edge detection. Its practicability and feasibility are demonstrated clearly by log time series data obtained in west Sichuan Province.

Karst is developed intensely in Heyetang viaduct.The crosshole electromagnetic wavepenetrating method has been used to detect type and scale of karst in Heyetang viaduct.The law of deep karst of the viaduct has been analysed according to achievements of drilling and crosshole electromagnetic wavepenetrating.Testing and effection have been discussed and evaluated.According to testing of drilling ,we have found that detecting precision of crosshole electromagnetic wavepenetrating is high. The comprehensive analyzing has made known that crosshole electromagnetic wavepenetrating method can be used to be an auxiliary mean on determining bearing layer of pile foundation.

With a practical example, this paper deals with the determination of the position of an underwater magnetic object by means of magnetic exploration. The utilization of the horizontal position of the maximal local magnetic anomaly reduced to the pole as the horizontal position of an underwater magnetic object and the estimation of the depth of the object's center by means of interpolating cut constitute two feasible methods. The results obtained by the two methods agree well with the real position of a magnetic object.

The feasibility tests of varied geophysical methods determined the physical character differences between the shell bank and the surrounding media. Data obtained from the Rayleigh wave survey and the reflection wave optimum offset survey were comparatively verified to detect the mode of occurrence of the shell bank in the working area and infer the boundary, buried depth and thickness of the shell bank. These data are very valuable for the protection of the shell bank in the planning of the new urban area of the Gangdong District.