This paper discusses how can a more successful and perfect role geophysics and geochemistry play in new phase of exploration. After a short review of the successes achieved by exploration geophysics and geochemistry (MGMR) in the field of mineral resousces in recent years, and increasing diffeculities and inadaptibility encountered in practice, it led to that we must undertake multi-discipline survey, involving geophysics, geochemistry,geology and drilling,carry ing forward their advantages, forming an optimum exploration, program and arrangement, to make great progress in searching for deep-seated deposits or to locate ores under complicated and unfavorable situation. Presented following co-untermeasures for geophysical and geochemical works henceforth. (1) Cover prospective regions systematically in scale 1:50000, which might pick out by com prehensive study of regional geological, geophysical and geochemical results. (2) Enlarge the train of thought in searching for minerals. It is necessary to explore and open the way for detecting ores indirectly. That is to locate deposits by mapping structures, magmatic rocks, altered rocks, mineralized zones and o-ther geological objects, which might having a bearing on mineralization in space or in genesis. ( 3 ) Improve and develop geophysical and geochemical methods and techniques, promote the ability for solving various geological problems. ( 4 ) Further atrenghen comprehensive study of data and pay close attention to test work for anomaly.

Logging has been an important method and means in gas prospecting. Nev ertheless, its efficiency for discriminating gas-bearing reservoir is low in that the prospecting method for gas is basically identical with that for oil. Having been tested over the known gas-bearing formation in China, the new logging technique for gas prospecting advanced in this paper is proved to be valuable in raising the efficiency of visually discriminating gas-bearing reservoir to find more natural gas resources.

This paper proposes a technique for adopting Airy isostatic compensation model to calculate the 5ˊ×5ˊ average isostatic gravity anomaly. In calculation, 5ˊ×5ˊ average elevation was used and A～Q zone was divided into three areas, i. e., the near, the middle and the distant terrain. Columns of 1ˊ40" ×1ˊ40", 5ˊ×5ˊ and 15ˊ×15ˊ are used respectively for the near, the middle and the distant terrain, and forward formulae for rectangular column, mass line and particle are adopted to calculate topography-isostatic corrections. It is demonstrated from the isostatic gravity anomaly map of a certain area in South China that the isostatic gravity anomaly can eliminate the regional field caused by variation in thickness of the crust, and thus show prominently the local anomalous field.

Mathematical statistical techniques were used to analyse the relationship between Bouguer gravity anomalies and topographic elevations over an area of more than 3,000,000 km² in Southeast China. Through a discussion on this relationship, a method was put forward for separating gravity anomalies, by means of which the gravity anomalies related to elevations and residual gravity anomalies caused by geologic structures of the crust were separated and corresponding maps compiled.This furnishes information for inferring density structures of different tectonic units and their possible tectonic frameworks at depth.

The study district was formerly considered to be a district possesing almost exclusively iron and copper deposits. Insufficient attention was paid to the search for gold ores, although this element was observed in known deposits. Using trace gold test technique, i.e., chemical spectroscopy with detecrion limit of 0.3 ppb, regional geochemical prospecting (stream sediment survey) has delimited two high gold terrains with Au >2ppb (Maocun-Binshan-Wuxian and Jiazhen) and 22 local gold anomalies, as prospective sites in search for goposits, In addition to known gold-associated occurrences, ten places are supposed to to be quite promising in gold prospecting, of them, two have already been proved to contain a middle-sized gold deposit and two good gold occurrences. Regional geochemical data of gold have been changing the attention of geological work in this study district. The regional geochemical distribution of gold assumes combined zonation trending northeasterly in the nosthwest part and northwesterly in the southeast part, with alternating high and low values which show an increasing trend of intensity from north to south. All this implies that gold distribution is controlled by NE and NW trending structures. The local gold anomalies, lying at the intersections of these two sets of structures, are distributed like chessboard. This paper indicates that Jiazhen and southern Binshan are two most favourable sites for gold prospecting in the study district.The Yenshanian intermediate-acid intrusive bodies related to iron and copper mineralizations have been evaluated for their gold potential. It is indicated that the F rock body, formerly regarded as nonproductive, is likely to contain gold, as is supported by the detection of Yicun and Geng;un gold occurrences.

The success in discovering ore deposits or prospects is usually attributed to regional geophysical or/and geochemical anomalies, which, even though containing only single anomalous point, should not be neglected. The adoption of dense -spacing search lines is not necessarily acceptable in that the weighing of exploration costs and the value of the targets to ce searched is indispensable. One of the problems involved in the layout of exploration strategy is the estimate of probability with which the search lines intersect geological targets of interest. Up till now, only single target with linear or elliptical shape has been dealt with. In the present paper, however, the author discusses multi-targets with arbitrary shape represented by sets of polygons, using analytical, numerical integration, and Monte Carlo methods for the comparison of results. FORTRAN programs are developed and run in an IBM-PCXT microcomputer with test examples of single and eight targets of complex shape, the Monte Carlo method may be especially applicable if uneven distribution of target orientation is expected.

This paper demonstrates that in karst areas, when either reflection wave or lateral wave on interface between ground (limestone) and air is negligible, and when either of these two waves, together with the direct wave in limestone, forms interference curve characterized by apparent extrema, the relative dielectric constant and phase constant of limestone are obtainable and, through dissolution of interference curve, amplitude of direct wave can be evaluated which, in turn, can lead to the determination of apparent absorption coefficient and apparent resistance. The corresponding approximate calculation is given, whose feasibility and precision have been affirmed by theoretical model and digit inversion of surveyed curves in fields of karst areas.These results also apply to other areas of low-dissipation media.

Taking into account the characteristics of hydrogeological and hydrologic logging work, the author has examined the commonlyused equations for calculating mineralization intensity or resistivity of strata water by means of self-potential curves, and then put forward his own calculating method and formula suitable for high-requirement hydrogeological logging work. It is considened that, of quite a few factors affecting diffusion-adsorption coefficient k_t, the variation in chemical composition and combination ratio of the solutions seems to be most important. Through statistical analysis, parameters of a, b, and k, for mixed solutions with different saline compositions are obtained, the physical implications of these parameters are clarified, and the reasonable acquisition of numerical values in practical work is discussed. Finally, the effectiveness of this me-thod is illustrated with the help of practical data and^comparison by diagrams. This also leads to an extension of its application scope.

The absence of self-stable circuit has affected the measurement precision of NE8420 automobile gamma energy spectrometer. This paper presents the circuit diagram, working principle and property-testing result of a self-stabilizer with ²⁴¹Am as the reference source.