Csillag Seminar Series
Date: October 9, 2019
Time: 12:00 - 13:00
Dr. Thomas Opel
Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research
Ice wedge paleoclimatology – The Siberian perspective
Dr. Thomas Opel
Ice wedges are a characteristic feature of northern permafrost landscapes. They grow in polygonal patterns due to the repetition of wintertime thermal contraction cracking of the ground and frost crack infill mainly by snowmelt in spring. Hence, ice wedges and their degradation forms, i.e., ice-wedge casts, are indicative of permafrost conditions. Ice wedges may survive even Interglacials and probably include some of the oldest ice preserved in the Arctic.
Ice wedges may be studied as paleoclimate archives by means of stable isotopes. In high latitudes the stable-isotope composition of precipitation (δ18O and δD) is sensitive to air temperature. Hence, the integrated climate information of winter precipitation is transferred to individual ice veins and can be preserved over millennia, allowing ice wedges to be used to reconstruct past winter climate. This specific seasonality makes ice wedges unique among terrestrial Northern High Latitude climate archives. Recent studies indicate a promising potential of ice-wedge-based paleoclimate reconstructions for more comprehensive reconstructions of Arctic past climate evolution.
This presentation briefly highlights this potential and reviews the current state of ice-wedge paleoclimatology. The focus will be on recent ice-wedge studies from the Siberian Arctic and Sub-Arctic, mainly from the Lena River Delta, the Laptev Sea Coast and the Batagay megaslump in the Yana Highlands of interior Yakutia.
Furthermore, this presentation discusses existing knowledge gaps and challenges and suggest priorities for future ice-wedge research to exploit the paleoclimatic potential of ice wedges, particularly in view of their unique cold-season information, which is not adequately covered by other terrestrial climate archives.