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The sedimentary rate of the Quaternary System in selected Iranian Sections has been estimated verve stratigraphy, soil stratigraphy and sedimentary cycle analysis. These studies yield an absolute age of about 720 ka for the base of the Olduvai Event and one of about 350 ka for the base of the Brunches Epoch. Current radiometric ages of these datum's are 1.87 Ma and 0.73 Ma respectively. Much lower absolute ages derived from fission track or radiometric methods are also occasionally reported for the two datum's. However, the latter ages are not introduced in formal geological time tables.
A statistical analysis of the depth of sections for the two datum's in numerous deep-Sea cores as well as the examination of the thickness and number of climatic cycles in the sections has established the time ratio of the two datum's with very approximation (estimated error than 2%). The computed ratio is at great variance with the Same ratio obtained from current radiometric ages. This is a clear indication of the unsoundness of current radiometric ages.