Collapse of marine-based outlet glaciers from the Scandinavian Ice Sheet
2013 (English)In: Quaternary Science Reviews, ISSN 0277-3791, Vol. 67, 8-16 p.Article in journal (Refereed) Published
We present a reconstruction of the timing and retreat rates of more than 2000 m thick Younger Dryas (YD) fjord glaciers in western Norway using a detailed chronology of 10 Be exposure ages from lateral moraines and 14 C dated end moraines. A primary conclusion is that ice margins retreated up the 120 e 170 km long fjords at mean rates of 240e340 m yr1 during the early Holocene. We further show that part of the south-western sector of the Scandinavian Ice Sheet collapsed in two distinct steps. The first step occurred between 19.5 and 18.5 ka BP as break up of the Norwegian Channel Ice Stream, which drained the ice sheet during the Last Glacial Maximum (LGM). The second step was the rapid retreat up the fjords mentioned above, dated to 11.6 e11.1 ka BP. During the interveningw 7000 years no net retreat occurred despite oscillations of the ice margin. This stepwise ice margin retreat strongly contrasts with the more monotonic decay of the ice sheet as a whole, indicating that water depths set the pace for climate-triggered ice margin retreat in this part of the ice sheet. Calving and melting of marine margins has dominated mass-loss from modern ice sheets in recent decades; however, the mechanisms and longterm (100 e 1000 yr) rate of ice-front retreat is less certain and empirical examples such as those given here may help in developing better numerical models.
Place, publisher, year, edition, pages
2013. Vol. 67, 8-16 p.
Marine ice margin, Ice-margin retreat rates, Calving rates, Last Glacial Maximum, Younger Dryas, Fjords, Hardangerfjorden, Sognefjorden, Jakobshavn Isbrae, 10Be exposure ages, Shorelines
IdentifiersURN: urn:nbn:se:su:diva-98030DOI: 10.1016/j.quascirev.2013.01.024OAI: oai:DiVA.org:su-98030DiVA: diva2:682218