[en] Described is the technique for data processing and interpretation of terrestrial gamma-spectrometric survey during prospecting for rare metal pegmatites. Using correlations of natural and technical dispersions of radioactive element distribution the measuring time in case of SP-3M spectrometer application is substantiated. Carried out is the statistical analysis of uranium, thorium and potassium distributions in rare metal pegmatites and enclosing rocks. It is shown, that the account of correlations between element contents in enclosing rocks permits to increase the resolvability of the method. Extraction of weak anomalies in porous sediments is carried out by means of complex geophysical indicator function