ABSTRACT
Various modifications of induced polarization method (IP) are widely applied in Russia to attain some important geological objectives, first and foremost in exploration for ore mineral and underground waters. Specifically, in Primorye, the induced polarization vertical electric sounding method (IP-VES) is practically unique in search for hidden deposits of complex ores, tin, wolfram and copper enabling to perform deep mapping of a section and to reveal zones of disseminated and veinlet-disseminatied sulphide mineralizations. Investigations by means of this method can be conducted in areas of composite geological structure having within geoelectrical section and under the condition of heavily rugged topography various subvertical and tilted heterogeneities and local objects. Local structures of ore control and ore localization are characterized, as a rule, by low resistivity and high polarizability. Among these are areas of intensive sulphide mineralization associating with zones of abnormally high fissibility. So, in Dalnegorsk and Kavalerovo ore districts all deposits and ore occurrences are within the limits of the IP anomalous areas. With the help of this method some promising deposits of underground waters, including Pushkinskoye deposit, have been prospected.
Specific conditions of application of IP method have required special approach to the field investigations technique as well as the interpretation technique for the material obtained. For this purpose various modifications of the field technique using IP-VES in complicated conditions of mountains and taiga in new areas as well as in ore field flanks have been developed. In this case the depth of exploration from hundreds of meters up to one and a half kilometer can well be achieved. But the successful use of IP method largely depends on the possibility to develop a close and authentic physico-geological model enabling to determine reliable parameters of the Objects under investigation. Experts are familiar with automatic systems of electric sounding interpretation in which data of resistivity method receive primary emphasis. The suggested technology of IP interpretation is based on mathematical modeling of horizontally-heterogeneous media, satisfactorily approximating real geoelectrical sections and representing combinations of smooth, tilted and sharply sloping layers including local heterogeneities. Preliminary analysis of typical geoelectrical sections of ore districts has been conducted, algorithms and programs for a number of horizontally-heterogeneous media models have been developed, peculiarities of spatial structure of IP for some models and configurations have been studied, algorithms of preliminary data process and initial approximation of models have been developed.
