Collaborative Research: Developing an Improved Chronology of the Southern Margin of the Scandinavian Ice Sheet

Washington State University, Pullman WA

Investigators

Abstract

This is a collaborative project whose principal objective is to develop an improved chronology of the southern (terrestrial) margin of the Scandinavian Ice Sheet (SIS) during the last glaciation in order to compare the history of this margin with that of the western margin of the SIS, with other ice sheets, and with other records of climate change in order to further evaluate the relationship between ice-margin fluctuations and climate change. The project will construct a chronology by dating (1) key organic-bearing units by AMS radiocarbon and (2) erratic boulders on moraine surfaces using cosmogenic nuclides (10Be and 26Al). Prominent recessional moraines delimit five to six retreat phases following the late Weichselian maximum at about 18,000 yr B.P., clearly suggesting a strong millennial-scale signal (five to six moraine building events between 18,000 and 10,000 yr B.P). However, dating control constraining the age of retreat phases along the southern SIS margin is all but lacking. The project will investigate (i) the age of the nonglacial interval before advance of the southern SIS margin to its last glacial maximum position, (ii) the age that the southern margin reached its last glacial maximum, and (iii) the area(s) of recessional phases of the southern margin that are prominently recorded by recessional moraines. The project will focus on deposits and landforms of the SIS in Poland, Latvia, Estonia, Lithuania, Belarus, and Russia.