Due to the interferences of several factors, the seismic data in the North Yellow Sea basin are characterized by poor quality, low signal-to-noise ratio and weak ineffective wave energy. In addition, multiple waves of the shallow layer are very strong, characteristics of reflection waves of the medium-deep layer are not clear, and the shallow layer has strong reflective screen. It is therefore necessary to adopt comprehensive interpretation which applies gravimetric and magnetic data in combination with seismic data. Based on analyzing features of the geophysical field and comparing seismic, gravimetric and magnetic data in plane and section, the authors selected key section lines to conduct joint inversion of seismic and gravimetric data and perform comprehensive integrated interpretation. The inconsistency between the interpretative result of gravity and magnetic data and that of seismic data is pointed out. All the achievements made have laid a foundation for further study in the North Yellow Sea basin.

Based on detailed studies of 1∶200 000 residual gravity anomalies in combination with aeromagnetic, physical and geological data, the authors delineated concealed and semi-concealed magmatic rock bodies, which is of some reference value and indicating significance for the study of temporal and spatial distribution and genesis of mineral resources closely related to gravity anomalies and rock body distribution.

his paper has described the principle of the magnetic source parameter imaging method. The precision for depth computation of magnetic source was achieved on the basis of some theoretical model tests, and the depth of magnetic bodies causing Yarlung Zangbo aeromagnetic anomalies was computed by using this method. The results provide a new basis for further study of the Yarlung Zangbo aeromagnetic anomaly zone.

1∶2 000 geological map and 1∶10 000 lithogeochemical survey covering 2.75 km² were completed in Justa area of Peru in 1997. Stratigraphic, structural and magmatic characteristics of this area were studied in detail, two mineralization areas and eight mineralization vein belts were outlined, in which ninety-six copper orebodies (veins) were delineated. Twenty-six copper anomalies were detected with the anomaly threshold of 800 ppm. Nos. 7, 8 and 13 copper anomalies form a large half egg pattern. Rocks in the mieralization area are rather broken and strongly altered. The half egg shape may represent the center of hydrothermal activity or mineralization. It was inferred that there might exist a huge primary copper ore body in the depth, and this predication was proved by Chariot Resources Limited which bought the Justa deposit in 2004 and announced that more than 2.6 million tones of copper were found on 28 February, 2006.

In Early-Middle Devonian, volcanic strata belonged to the Altai epicontiental rift zone. There exists an important type of ore deposit known as the Qiaoxiahala copper-(gold) deposit, whose genesis was not determined in the past. Based on studying its ore-forming environment, the ore-controlling features, the volcanic activity related to mineralization and the metallogenic material sources, the authors hold that the Qiaoxiahala copper-(gold) deposit is a kind of stratabound skarn deposit formed by volcano-exhalative sedimentary activity.

By processing 1∶50,000 strem sediment dete in Lianghekou area,A lot of element anomalys ws point.element assembled ws classtyed in relsut of R mode factor analysis. Analyzing from the element association characteristic, evaluating anomaly for prospecting significan , 7s prospecting area ws pointed. No1 anomaly is the best prospecting target.

The Wenquan porphyry molybdenum deposit in West Qinling area occurs in Indosinian complexes, with the wall rocks being K-rich calc-alkaline rocks. CIPW calculation shows that they are of the normal type, and in Q-A-P diagram they are all plotted in the adamellite region. Trace element analyses show that Mo, Cu, Ag, As and Bi were closely related to mineralization, and REE geochemical studies reveal that the rocks are characterized by enrichment of LREE, good fractionation and strong Eu depletion. It is thus concluded that the rocks were products of crsut-mantle magmatic mixture and provided ore-forming materials.

Both oil and gas have components of mercury element, and the physical and chemical properties of mercury cause this element to move upward in the oil and gas accumulation.According to types of sampling media and pretreatment methods, the analytical methods for surface mercury can be divided into oil gas mercury,heat-released mercury and soil total mercury, whose indices all show very good oil and gas indicating significance and are also very effective in tracing of fault belts.

Based on tests of pre-enrichment gold in water, the authors chose two known gold mines with different natural landscape conditions and different genetic types in central Inner Mongolia to test the validity of this technology. A gold pre-enrichment method in water was established with polyurethane foam cleaned by hydrochloric acid. A quick and simple field method for gold pre-enrichment in water was developed. It is found that the gold content of water in the dry season is higher than that in the rainy season. Hydrochemical survey should be usually conducted in the dry season so as to guarantee the consistency of the results. Good gold anomalies were detected in the Donghuofang gold mine, the Laoyanghao gold mine and the peripheral Hejiaoyi belt, which shows that the method is effective. In the area of loosen thick overburden, the performance of the water chemistry survey led to the discovery of gold anomalies which could not be found by stream sediment survey and soil survey in the past, suggesting that the method discussed in the paper is useful in search for blind gold deposits.

In ore-hosting wall rocks, late stage vein rocks and altered rocks of volcanogene hydrothermal ore deposits, the contents of ore-forming elements Pb, Zn and Ag are high, the element associations of ore bodies are complex, the primary anomalies are very developed, and there exists primary zoning. The frontal elements are I, Hg, As, Sb, B and Ba, the near-ore indicator elements are Pb, Zn, Ag, Au, Cd, Mn and Cu, and the rear or underneath indicator elements are Cu, Mo, W and Sn. According to the distribution of the indicator elements and the zoning of the primary anomalies in the ore deposit, the authors put forward geochemical indices for judging the denudation extent and evaluating anomalies of the ore deposit, and set up geochemical ore-prognostic criteria for this kind of ore deposits.

Electric survey has yielded good results in complex belts, deep formations and large-sized structures. Upper Paleozoic coal measure strata in Hefei basin present imbricate reflections on seismic sections, composing the basement of Mesozoic basin. Nevertheless, the reflections are obscure in some areas, and hence it is difficult to trace and describe the spatial distribution with the help of seismic data. New electric techniques such as seismic fitting processing, geological horizon imaging and 3D imaging processing are described briefly in this paper, and it is shown that, with these techniques, Permo-Carboniferous electric horizons can be extracted quite satisfactorily in Hefei basin. Coal measure strata were traced on seismic sections, and the distribution of Permo-Carboniferous strata was roughly determined, which makes up the foundation for further basin research.

The small circle line transient electromagnetic method has such advantages as easy and convenient installation, unlimited working space and high efficiency. This paper deals with the application of this method to some special landscape areas like the plateau frozen earth area and the crushed stone accumulation slope area and describes the effectiveness of this method.

The drawing of the dispersion curve in the frequency-wave number domain often yields different results. This paper studied this problem in multi-channel transient surface wave exploration, carried out the contrast experiment by using three different seismic sources, and produced different dispersion curves, which have different unique depth ranges. It is thus held that the dispersion curve uniqueness makes up the basis of the correct geological interpretation.

Based on the natural gamma log curves of acid tuff and clay rocks of acid volcanic events, the author here queries the arguments that radioactive intensity of sedimentary strata will grow with the increasing argillaceous materials and that the natural gamma value and the empirical equation can be used to calculate contents of argillaceous materials. The natural gamma curve of acid tuff has high anomaly response, which can not be interpreted as the response of the mudstone. If we regard the gamma curve of high anomaly exclusively as anomaly of mudstone, the viewpoint is obviously one-sided. The gamma values of clay rocks of various volcanic events are different very considerably, and hence the utilization of the gamma values to calculate the contents of argillaceous materials is likely to result in remarkable errors. In the end of this paper, the author has explained in brief the gamma curve of the bauxite bed and discussed the prospects of the nuclear log.

As cross-well seismic exploration can avoid the impact of the low-velocity layer and weathering layer, it can acquire relatively high frequency seismic signal. After processing, fairly high resolution velocity and reflection imaging can be obtained. During 2004-2005, eight cross-well seismic profiles were processed in Ken 71 Block, Shengli Oil Field. In accordance with the characteristics of raw data, the authors studied tomography, tube wave attenuation, VSP-CDP and finite angle stack, and completed the cross-well seismic data processing. The analysis and interpretation of the final results show that cross-well seismic exploration can recognize small faults, small structures and thin reservoirs between two wells.

A series of field investigations and tea collections were conducted in the West Lake Tea Plantation of Hangzhou. The authors aimed to search for the main source of Pb contamination by measuring Pb isotope compositions in soils, tea, coal, automobile exhausts, and aerosols. The results show that the dissoluble lead is homogenous whereas the residual lead is heterogenous. Lead content of the rinsed tea decreases evidently, whereas Pb isotope compositions do not vary significantly. In addition, Pb in tea is derived from the same source as that in the atmospheric deposition. The 206Pb/207Pb ratio in topsoils, aerosols and coals is similar to that in tea. At the same time, the 208Pb/(206Pb+207Pb) ratio in topsoils, aerosols and gasoline is similar to that in tea, but the Pb content of coals is somewhat higher. Lead in tea is homogenous and has nothing to do with the background values of different tea plantations. The adsorption and uptake of lead by tea are completed by atmospheric deposition in the process of coal gasification and combustion. In addition, the automobile exhaust is one of the main sources of lead contamination.

Investigations on the rock-soil geochemical system for the producing area of 'Zhonghuashoutao' peach have been performed in Laixi county.The results show obvious differences of geochemical characteristics in this rock-soil system. Some elements are rich in specific rocks,(e.g. K₂O and Na₂O in granite, B in base rock, MgO and CaO in canaanite and Mn, N and P in leptite). As a result, the related soils have the similar geochemical characteristics, whereas the tendency of variations for these elements is not significant .The nutrient elements which are needed for peach trees are found quite different in different soils. For instance , canaanite and base rocks are abundant in Ca, Mg, Mn, N and P, while leptite is sufficent in N, P, Fe and B. However, the nutrient elements are found insufficently in the large grantite soil areas.The effective elements of N and P have high levels in the soils of peach gardens, while B Mn, Mo, Fe and organic matters are relatively low in concentrations. It is suggested that beside the enough N, P and K, some trace elements such as B, Mn, Mo, Fe, Ca, Mg as well as organic fertiltzers must be used to improve the soil quality.

The true three-dimensional modeling is a common subject in such fields as geology,three-dimensional GIS,scientific visualization and engineering application. This paper has presented a new three-dimensional data model based on TEN, and introduced TEN's generation algorithm and steps. Practical examples indicate that this algorithm can satisfactorily produce the tetrahedral unit grid of the arbitrary shape three-dimensional geological body.

There exists lots of profile mapping work in geophysical survey, and thus a rapid and efficient automation mapping method is highly needed. This paper has described the application of Grapher automation to the rapid drawing of geophysical profile map and provided some automation script codes and mapping examples to illustrate the realization of delicate mapping and high efficiency.

The key of the tomography lies in solving the equation group whose coefficient matrix is a large sparse one, and the LSQR algorithm is used here. This algorithm has many advantages that other iterative methods don't have. The calculation instance has proved that the results of the LSQR method are clear and reliable, and hence it has been widely used.d:\PDF\.pdfd:\PDF\.pdf

The forward numerical simulation of the finite difference wave equation is mainly used to solve such problems as difference scheme, focal choice and boundary condition processing. The solution of these problems can play an important role in correct numerical simulation of the wave equation. Based on discussing the forward numerical simulation course of the finite difference wave equation,the authors analyzed the error source in forward simulation and the means for reducing the error.

Based on the combination of numerical simulation of the elastic wave equation with Zoeppritz equations, the authors studied characteristics and regularity of elastic wave propagation in solid-solid interface and high and low velocity interlayers between wells. The main types of elastic waves were classified, including a specific type of surface wave produced by secondary source formed in the interface between the source well and the receiver well. It is also found that the predominant reflection waves are wide angle refection. The authors analysed he wide angle reflection phenomena by forward simulation of seismic records and thus obtained the results of amplitude and phase sharp changes as well as polarity inversion of wide angle reflections at the critical angle point, corresponding to the change of the reflection coefficients into the complex numbers. Furthermore, the determination of layer velocities by reflection characteristics of the critical angle reflections and the reflection point was suggested. The elastic wave fields formed are simple when the source is located in the high velocity interlayer, whereas the elastic wave fields formed become complicated when the source is located in the low velocity interlayer. The guide waves show obvious dispersion when they are propagated in the low velocity interlayer and their amplitude and frequency are closely related to the velocity and thickness of the low velocity interlayer. The lateral changes and connectivity of the low velocity layer can be estimated by the guide waves.

The Integrated Mining Geophysical Technology for detecting the location and water content of the collapse column is put forward in this paper. The radio-wave penetration method can detect the relative locations of abnormal structures such as collapse columns, faults and thin coal layer areas, and the mine transient electromagnetic method can estimate the water-containing situation of these structures based on the variation of the resistivity in the detection range. Emphasis of this paper is placed on describing the application of the radio-wave penetration method and the mine transient electromagnetic method to exploring the collapsing column in No.7218 working face coal layer. The obvious reflection of the radio-wave penetration method to the electrical property of the hydrated structure is discussed theoretically, the application of the synthetic curve method and tomography to data explanation is studied, and the hydrogeological characteristics shown by the "V" and semi-"V" synthetic curve are also explained.

The electromagnetic tomography technique is a new widely-used geophysical method. It is highly accurate, rapid and economical. This paper describes in brief the primary theory and working procedure of electromagnetic tomography. Combined with several engineering examples, this paper illustrates the structural forms of underground media relatively intuitionally and clearly by the form of 2D image. This result provides an important basis for the engineering geological survey as well as the evaluation of the safety and stability of site bases and dams.

Landslide fissure is the evidence to define the size of landslide, analyze the formation mechanic character of landslide, forecast the development tendency of landslide, direct the inspection and control of landslide. Ground penetrating radar (GPR) is a new kind of shallow subsurface geophysical exploration instrument, it can be used under kinds of bad fieldwork conditions. This thesis analyses the principles, establishes the general mode of Landslide fissure survey of GPR, takes the exploration of Mt.Zhaozixiu, Huaying, Sichuan province for example, acquires high quality image which can show the location, direction and depth of the fissure clearly. The research shows that using GPR in landslide fissure survey is expedient and effective.

Aimed at solving the problem of typical defects of shield tunnel lining, this paper established the numerical dielectric models. Numerical simulations of radar wave performance in models for typical detects were conducted. The simulation algorithm used was the finite difference time domain solution, with the perfectly matched layer absorbing boundary conditions for these attenuation models. The scattering of the steel-bars in the tunnel segment was fully considered during FDTD simulation. The simulated results could be a good guide to GPR data collection, processing and interpretation for shield tunnel lining detection.

This paper mainly introduces the principle and working method of Ground Penetrating Radar, emphasizes the application in tunnel liner quality detection. Combined with the practice work, describes the common problem existing in tunnel liner in different categories, points out relevant radar maps and features of the wave to approve the accuracy of the Ground Penetrating Radar system.