A specific, radium bearing type of barites has been known from the Ohře (Eger) Rift, a region of Cenozoic volcanic activity
in northwestern Bohemia, Czech Republic, since 1904. Barites from Karlovy Vary, Teplice and Děčín areas have been studied
to elucidate geochemical history of these specific samples. Low background radiometric method using high-resolution gamma-ray
spectrometry has shown that radioactivity of these barites (up to 8 Bq g
−1) is carried by
226Ra, which is not in equilibrium with the parent
238U. In all samples, uranium activity was below 0.005 Bq g
−1––the detection limit achieved by instrumental neutron activation analysis. The alpha track method on a crystal plate has
shown that
226Ra is accumulated in surface layers or crystal cracks, therefore, the crystal rims must be relatively young, not older than
10–15 thousand years. In a lead fraction isolated from the barites, concentration and isotopic composition of lead were determined
by photon activation analysis and ICP MS, respectively.
Keywords Barite - Radiometry - Lead isotopes - Alpha tracks - Activation analysis