A MODEL FOR THE VERTICAL SUBSURFACE RADON TRANSPORT IN “GEOGAS” MICROBUBBLES

Based on the phenomenon of “geogas”, rising in the form of microbubbles from deeper regions, the authors have developed a new model for the transport of radon released from deep sources, and a new method for its detection. The advantage of the new model compared to the earlier ones is the elimination of the well-known problems of the radon emanation research methods (penetration depth, reproducibility, etc.), and it provides a qualitative and quantitative description of the transport mechanism, which is realistic from both geological and physical viewpoints. The authors emphasize the role of groundwater and gases of deep origin in the movement of radon, briefly discussing possible sources of these gases. The problems of detecting the radon below the water-table with track detectors are reviewed and the connection between the rock physical para­ meters (tortuosity, porosity, grain size distribution) and transport characteristics is investigated in detail. Assuming different geological conditions and rock physical parameters theoretical vertical radon concentration and track production profiles were calculated. Finally detectability of deep radon sources depending on geological conditions is analysed and methodological recommenda­ tions are made for the more efficient use of the radon emanation uranium exploration methods.