The extent of the Late Weichselian ice sheet in the southeastern Barents Sea

Abstract

We have compiled a large number of seismic records and descriptions of sediment cores obtained from the southeastern Barents Sea (Pechora Sea) by former Soviet Union institutions. Five major seismostratigraphic units (SSU-I–V) were recognized. The oldest till (SSU-V) is mainly confined to the southernmost area and is covered by a 100–150-m-thick wedge of Middle Weichselian marine sediments (SSU-IV) distal to the mouth of the Pechora River. Three Late Weichselian ice sheet margins are identified on the Pechora Sea shelf. The oldest is named the Kolguev Line and it marks the southern limit of the youngest till sheet (SSU-III) in the Barents Sea as well as the northern, erosional limit of SSU-IV and -V. The Kolguev Line marks the maximum extension of the Barents Ice Sheet during the Late Weichselian. The Kurentsovo Line, which is located 50–100 km further to the north, is much more expressed than the Kolguev Line and corresponds with long ice-pushed bedrock ridges and till ridges. Up to 100-m-thick accumulations of glaciomarine sediments (SSU-II) were mapped on the southern side of the Kolguev Line whereas less than 10–20 m where found on the northern side of the inferred ice sheet margin, indicating that the ice front remained at this position for considerable time. The youngest line is the southern continuation of the Admiralty Banks moraines, which have previously been mapped along the western margin of Novaya Zemlya. The Kolguev and Kurentsovo lines were both formed by an ice sheet centered in the Barents Sea, whereas the Admiralty Banks moraines were deposited from an ice sheet over Novaya Zemlya during the final stage of the Late Weichselian, possibly during the Younger Dryas. Submerged shorelines of Late Weichselian/Early Holocene ages have been identified on the shelf down to a water depth of 50–70 m indicating a modest glacio-isostatic depression that partly compensated the sea-level fall during the last glacial maximum.