[en] A method is described for prospecting for mineral deposits having radioactive gaseous decay products and which diffuse vertically through the earth's structure into the atmosphere. The method comprises: a) sensing the radioactive gaseous decay products in the atmosphere, b) charting an azimuthal sector of density flow of the gaseous decay products above the earth's surface, c) sensing geostrophic wind flow above the density flow of gaseous decay products and modifying accordingly the charting of the density flow, d) horizontally tracking the density flow towards the deposit from which it has diffused and e) marking the deposit within the earth, as the density flow and the diffusion vertically from the deposit coincide. (author)