Regional geomorphic markers in the Cenozoic history of East Arctic

Abstract

The relief development on the East Arctic shelf during the Cenozoic directly resulted from the Arctic Ocean formation and can be subdivided into four stages: second half of Paleocene to Early Oligocene, Middle Oligocene to Early Miocene, Middle - Late Miocene, Pliocene present day. Each stage duration was about 12 to 15 mln years with the exception of the last one which has not yet been completed. In each stage a marine transgression reflects changes in the structural plan which includes transformation and growth of the area of subsidence and associated uplift of regional barriers between the basins. Other events of the Cenozoic geologic history of the region occurred during the said stages, such as the ice cover formation in the polar basin (began in the Late Miocene -- Early Pliocene and was completed to the Middle Pliocene), seasonal freezing of the ground occurred at the Oligocene - Miocene boundary and again at the end of Miocene, permafrost developed since the Middle Pliocene.