Diatoms of Marine Isotopic Stage 5 Deposits of the Western Alaska

An 8-10 m marine terrace of the western Alaskan coast was investigated here. Three diatom associations were identified in these sediments, reflecting climatic and sea-level changes during the first interglacial period of the late Pleistocene (MIS 5). A complex of marine diatoms was found in sandy sediments at the section base. Higher in the section they are replaced by swamp diatoms found in peat unit. A marine coastal complex was discovered in the loams at the top of the section. These three assemblages are correlated with substages 5e, 5d, and 5c of Marine Isotope Stage 5 and stages of the Pelukian transgression of Alaska. The relatively high position of the layers bearing marine diatoms in relation to the modern coastline indicates the emergence of glacioisostatic movements after the glaciation of late Wisconsin.