Seminar by Bernd Etzelmüller, Professor, Dept. of Geosciences.
"Icelandic permafrost dynamics since the Last Glacial Maximum – model results and geomorphological implications"
Abstract:
Iceland’s landscape is notably dynamic due to predominantly young bedrock combined with high geomorphological process/erosion rates yielding large material production and associated mass-movement. This is particularly so in the periglacial realm and today, permafrost is widespread in Iceland’s highlands and mountains over c. 800 m a.s.l. and sporadically in palsa mires in the central highlands. During the late Pleistocene and Holocene, Iceland’s periglacial environment varied in time and space, dominated by both glacial and periglacial processes. To evaluate the dynamics of permafrost in Iceland since the last deglaciation, we couple the output of a 3D, time-integrated ice sheet model to a transient permafrost model (CryoGRID 2) applied over the last glacial maximum (LGM) through to the present. Our results demonstrate that permafrost was widespread in the early deglaciated areas of western, northern and eastern Iceland after the LGM, and up to 20% of the land area of Iceland was underlain by permafrost throughout the late Pleistocene. This influenced geomorphological processes and landform generation, as relict rock glaciers were abundant near the coastal areas of Iceland, and their formation was initiated with the early collapse of the marine-based ice sheet in these zones and the aggradation of permafrost. Permafrost degraded rapidly after the Younger Dryas with a marked impact on slope stability, and as the permafrost that formed during the Little Ice Age now thaws, a consistent increase in slope failure and mass-movement has been observed. Our study demonstrates that large regions of Iceland have been underlain by permafrost for millennia, facilitating landform development and influencing the stability of steeper slopes.
About the seminar:
This seminar is offered by the Section for Geography and Hydrology at the Department of Geosciences, University of Oslo. The seminar is announced as a lunch seminar so bring your lunch if you want to.
Everyone is welcome, and especially students.
The lunch seminar team.