The telluric electromagnetic sounding in Panxi and Longmenshan areas andtheir neighbouring districts has detected an intracrustal low resistivity layerburied 11-37km below the surface with thickness of 5.5-11km and resistivityof several to tens of ohms, which is likely produced by partially molten graniticsubstances. This layer nearly disappears along the Panxi and Longmenshanmajor structural belt. The thickness of lithosphere in western Sichuan is deter-mined to be 80-143km, and the lithosphere west of the above two major stru-ctural belts obviously becomes thicker. Along the major structures there existdeep-seated high resistivity anomalies, which are apparently consistent with thegravity and magnetic anomalies. lt is thought that these deep-seated high re-sistivity anomalies are probably brought about by mantle substances which flow-ed upward in large quantities at early stage, and that they must have hadintimate relationship with the most important mineralization in this area, thusdeserving further investigation.

The geophysical field of the Dachang ore field displays gravity low combi-ned with ringed magnetic anomalies as its macroscopic character, which is anindication of the ore fie1d composed of concealed granite of high-level empla-cement and its thermal metamorphic zone; microcosmically, this field showsgravity outward convex combined with superimposed magnetic anomalies or IPanomalies, which is an indicator for ore deposits of different types and atdiverse denudation levels. An investigation of these indicators seems to be ofsignificance in looking for concealed ore deposits in a metallogenic area or belt.

The Erlian basin group comprises tens of relatively concentrated yetseparated small basins. As most of these basins are completely covered by agreat thickness of Cenozoic sediments, geological survey has to depend only ona small number of drill holes and therefore meets with a great deal of difficul-ties. The present paper presents some techniques for recognizing and delineatingthe basins, for calculating the buried depth of the basins as well as for study-ing basement structures by using geophysical prospecting data, with a descrip-tion given concerning the complex situation met in the work. As only partsof the basins contain coal, and different coal-bearing basins frequently havediverse coal-bearing structural positions, the assessment of coal potential of thebasins and the determination of coal-bearing horizons make up the mostdifficult technical probroms in coal prospecting. Besides making a brief accountof the traditional technique for analysing sedimentary environment and thenevaluating coal potential of the basins by utilizing geophysical prospecting data,this paper deals relatively in detail with a new method for analysis of sedimen-tary environment by employing geophysical prospecting data-technique ofvertical analysis, describing the process of its emergence and development andgiving some practical examples showing its effectiveness.

The principle of differentiating magnetic anomalies by discriminant interp-retation technique lies in utilizing characteristics of electromagnetic anomaliesover magnetic deposits and magnetic rock bodies as well as correlation coefficientbetween aeromagnetic anomaly and anomaly of airborne electrical prospectingas characteristic parameters to establish linear discriminant function, and,according to certain operation regulations, converting multivariates into a newsingle variate. This variate is then used as a discriminant index to performintegrated appraisal and classification of unknown magnetic anomalies.The discriminant interpretation carried out on discriminant values obtainedfrom 13 survey lines over 8 magnetic anomalies suggests the effectiveness ofthis method, which can be used to conduct integrated appraisal and classifica-tion of magnetic anomalies objectively, rapidly and accurately.

Based on abundant data on contents of halogens in strata and intrusivebodies of various ages surrounding the Dongguashan copper deposit as well as inthe deposit, this paper makes a preliminary discussion on such problems asdistribution of halogens, major ore-bearing horizons and material sources formineraization. In addition, it describes the ore-forming processes, indicates areasfavourable for existence of rich orebodies, and suggests proper geochemical pro-specting techniques.

Since 1981,experimental recearch work of applying IP method to large-areauuderground water survey has been conducted in different geomorphologicalunits and diverse stratigraphic and lithologic areas such as loess land ofLingbao County, hilly country of Xinan County and plain area of Xiuwu County,with a total surveying area of 1933.8km². This paper outlines the basic techni-ques of carrying out large-area survey, draws contour maps of ρ_s、D、 η_s、J according to large quantities of measured data, and, on such a basis, makescorresponding inferred geological diagrams including sand-gravel confined water-bearing bed of deep-buried Lower Pleistocene (Q) fluviolacustrine facies in loess land (Ling-Shan faulted basin) of Lingbao County, the Nangang undergroundreservoir in hilly country of Xinan County and the Qinhe old channel. Drillinghas demonstrated fine geological effects and economic benefits of these data,with the prediction of water-bearing bed reaching an accuracy of over 95 percent.

This paper recounts the principle, program flow diagram and applicationcases of automatic interpretation of the field data callected by shallow firstarrival refraction survey using t_o and differential time-distance curves with thehelp of a microcomputer. A simple and easy method for correction of seismicsource depths is adopted in program design to simplify the procedure of seismicsource depth correction. The automatic interpretation by means of the microcom-puter enables us not only to raise the work efficiency by hundreds of times,but also to eliminate the errors caused by such aspects in artificial interpreta-tion as spread of points, drawing, auxiliary line drawing and reading.