Hydrogeology, engineering geology and environmental geology, which are closely related to economic construction and social development, have gained various achievements in the past ten years. In this process, geophysical pros pecting, remote sensing and geochemical prospecting have been applied to some extent and played a notable role. In the new run of hydrogeological, engineering geological and environmental geological exploration, we ought to bring geophysical prospecting, remote sensing and geochemical prospecting into full and more, effective play. This paper advances some suggestions concerning the measures for attaining this object.

This paper summarizes the main geological outcomes, technical advances and experience gained since the Hydrologic Geophysical Prospecting Meeting held in 1978, especially since the Urban Geophysical Prospecting Symposium held in 1984. The paper holds that the geophysical-geochemical prospecting and remote sensing work should follow MGMK’s guiding principle about the new round of hydrologic-engineering-environmental geologic work and play a full role in the work. After bringing up eight basic tasks for future work, it suggests that five measures should be adopted.

Based on an analysis of abundant electrical sounding and electrical logging data obtained in Hebei plain in the past thirty years, in combination with hydrogeological and remote sensing data, this paper summarizes the electric parameters of Quaternary sediments of different lithologic characters, under ground water of various mineralization intensities and soils with different salini ties within the critical depth of salt accumulation in soil it also describes the outcomes obtained by utilizing geophysical prospecting data to investigate such hydrogeological problems as the shallow-layer hydrogeological division of Hebei plain, the division of shallow water enrichment in piedmont plain, the distribution of saline water bodies, the development of shallow fresh water in the saline water area and the division of salinized soils. These results reflect regional electric properties of the Quaternary water-beaiing composite geolo gical bodies in Hebei plain and demonstrate the satisfactory effects of geophy sical prospecting method in solving the related hydrogeological problems.

In recent years, the non-destructive check technique for quality of foun dation pile has developed rapidly. The geophysical prospecting workers'parti cipation in this work, in particular, has not only opened up a new appli cation field for geophysical prospecting, but also brought new vitality for the pile- check technique. This paper summarizes the application of some geophysi cal prospecting methods to the check of foundation pile quality; their pre sent application situation, the achievements gained and the existent troubles. It also recommends some techniques which show latent potentiality but have not yet been employed. Finally, it advances some tentative opinions concern ing the future development of this method.

This study is guided by a thread of thought which can be stated as fol lows: first, the geological environment and factors governing ore-formation are transformed into geochemical environment and factors; then, the ore-control ling geochemical environmental factors are transformed into indicators for geochemical exploration. The siderite-Pb, Ag and Zn deposti.s of the Zhashui-Shanyang metallogenic belt in southern Shaanxi have proved to be formed mainly by syngenctic sedimentation from a submarine hot brine and control led by relatively sealed depressions on the sea floor and by syngenetic faults. At the geological reconnaissance stage, however, it is difficult to find syngene-tic faults and depressions on the sea floor by geological observation. In order to solve this problem, we consider that, instead of the geological factors, the geochemica! environmental indicators, i. e., high boron and barium contents of argillaceous rocks reflecting high salinity of hot brines, can be used to indica te favorable ore-forming areas. A comparison of boron and barium contents of argillaceous rocks from the ore-containing strata near and far from the ore depo sit has confirmed this supposition. Boron-metiric survey and barium-metric survey were carried out at the Heigou ore district, and the result shows that large distinct boron and barium anomalies are coincident perfectly with the known ore bed. This proves that the distribution of boron and barium in the sedimentary strata not only reflects well the high salinity environment for syngenetic sedimentary ore-formation, but a’so serves as an effective indicator in prospecting for this type of stratabound deposits.

The study of ash content in raw coal is an important part of coal quality analysis. Using Series Ⅲ digital logging instrument, the author conducted log ging work along nearly one hundred boreholes in Heche coalfield of Shanxi pro vince, Yongcheng coalfield of Henan province and Huainan coalfield of Anhui province and thus acquired large quantities of initial data. This has laid a so lid foundation for the application of logging data to the study of ash content of raw coal in the coal bed. This paper describes the techniques and analyti cal results of regression analysis, one of the probability model analytical me thods.

Based on a study of remnant magnetism of pyrrhotites from Upper Jura ssic sandstone in Qaidam block and from Cambrian and Ordovician limestone in Ili block, this paper points out that the stability of remnant magnetism of pyrrhotites lies in their genetic differences. A knowledge of remnant magne tism stability of pyrrhotites is of great significance in determining minerali zation epochs, interpreting magnetic anomalies and solving some geological-stru ctural problems.

The round domain fan-shaped column vicinity-area terrain correction me thods used previously all show certain limitations and drawbacks in that they usually fail to simulate complex terrains and therefore suffer from relatively low precision.A polyhedral analytical method for square domain vicinity-area terrain correction is put forward in this paper. By using triangle to fit the terrain and adopting square as terrain correction domain, the calculation precison is greatly raised and the calculation is readily realized. A few examples, given in this paper demonstrate that the precision of this method is at least over ten times higher than that of the round domain fan-shaped vicinity area terrain correction.This method also applies to medium-distant area high precision terrain correction calculation.

The boundary element method(BEM)is a new numerical method. As it can reduce the dimensionality of the studied potential field problem, this me thod, as compared with FEM and FDM methods, has such advantages as sim plicity and convenience, less data quantity, rapid calculation and high preci sion. In consequence, this method has been successfully used to solve the cal culation for apparent resistivity anomaly or a three-dimensional geoelectric model which can hardly be worked out by FEM and FDM methods.This paper deals with the principle and numerical processing technique of using BEM method to solve the potential fiel dproblem of the three-dimen-sional geoelectric body of a point source field under the condition of horizon tal or undulate suiface with some calculation examples given: numerical solu tion and analytic solution of apparent resistivity over the conductive spheri cal orebody; plane- section curves or apparent resistivity along different survey lines over a conductive spherical orebody; combined profile curve of apparent resistivity over a conductive ellipsoidal orebody and its topographic correction.The consistency between the numerical solution and the analytic solution of BEM method for apparent resistivity and the obvious effects of three-di mensional topographic correction demonstrate that BEM is an effective method for solving potential field problem of an arbitrary three-dimensional geoelectric model. As it has realized the calculation for spatial potential field over an arbitrary three-dimensional geologic body, this method will undoubtely push forward the electrical prospecting research and play an important role in raising geological effects of the electrical prospecting.