Published September 2010

To the question of radioactive elements disribution in Lower Pliocene sediments of the South Caspian depression

F.D. Hasanov

U. Sh. Meghdiyev

The article focuses on quantitative content and distribution of radioactive elements (U, Th) in PS of Azerbaijan in sections of Absheron peninsula (Atashgagh), Kur depression (Neftchala, Garabaghly), Absheron (Neft Dashlari, Bakhar) and Baku (Bulla-deniz) archipelages, in Red rock series of Turkmenistan this problem has been studied on structures Lam and Zjhdanov bankasi. U and Th distribution type is normal in lower and in upper divisions. U has three-top curve in the upper division and Th has two-top curve both in the upper and lower divisions, so U and Th according to granulometric profile (Sandstone-clay) have a weak sorting. This shows the participation of several sources of removal less configuration of sedimentation basin, lava rate of sedimentation, mud flows and influence of elision catogenesis in sedimentation of studied section. Th behaviour is different in both series as its average content and degree of dispersion increase in lower division of PS. By widening the coastal line the sources of removal influence greatly, they cosist of magmatic rocks from Shakh-Adam and Garadagh uplifts represented by acid intrusive, effusive and dyke rocks where Th is a little. In PS section due to basin widening additional terrigenous material made a dilute effect on Th quantitative content. Relative weak dispersion of these elements in Neftchala and Garabaghly sections can be explained by important role by local sources of supply in sedimentation (mud volcanos, oil, iodinebromine waters). High average content and dispersion degree in the upper division show the widening of sedimentation basin contour during sedimentation of the PS upper division. So, PS and KaS sediments formed in fabourable for oil and gas formation conditions of sedimentation transgressive cycle, rapid subsidence of basin bottom and burial of organic remnants in restoration medium. Large localization of radioactive elements (U, Th) in structures sections, hydrocarbons potential content allow to consider them as search geochemical criteria for oil and gas deposits.