Spatial Distribution of Thorium Concentration in Afyonkarahisar-Sandıklı-Şuhut Region

Although at least 20 elements are known as natural radioactive, only u (uranium), th (thorium) and k (potassium) are important elements in nuclear geophysics. stable nucleus of 232th is pb and in this chain there are 10 isotopes. 208tl decay chain produces characteristic gamma radiation (2.62 mev). the 232th concentrations have been measured using portable gamma-ray spectrometer, for about 180 seconds counting times at 1169 points with known geographical coordinates. the variation of eth concentration has been mapped in afyonkarahisar district (sandıklı, şuhut, haydarlı). eth concentration values ranged between 0-80 ppm with different regional lithology. it should be noted that high concentration values were obtained in volcanic rocks and altered volcanic zones.