Institutskolloquium Physische Geographie
What happens when ice meets ocean and why would we care?
Antarctica is surrounded by floating ice shelves which provide the interface for ice-ocean interactions, and which decelerate the ice mass flux from the continent throug buttressing. Ice-shelf integrity is thus an important component controlling abrupt sea level variations. Ice-shelf channels are long curvilinear tracts of thin ice found on Antarctic ice shelves. Many of them originate near the grounding line, but their formation mechanisms remain poorly understood. Here we use ice-penetrating radar data from Roi Baudouin Ice Shelf, East Antarctica, to infer that the morphology of several ice-shelf channels is seeded upstream of the grounding line by large basal obstacles indenting the ice from below. We interpret each obstacle as an esker ridge formed from sediments deposited by subglacial water conduits, and calculate that the eskers’ size grows towards the grounding line where deposition rates are maximum. Relict features on the shelf indicate that these linked systems of subglacial conduits and ice-shelf channels have been changing over the past few centuries. Because ice-shelf channels are loci where intense melting occurs to thin an ice shelf, these findings expose a novel link between subglacial drainage, sedimentation and ice-shelf stability. Moreover, our findings have implications for geomorphology because Eskers are interpreted world-wide to reconstruct the extent of former ice sheets, but hitherto no example under a contemporary ice sheet has been available.
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– Pflichtveranstaltung im Rahmen des Bachelor-Studienplan / neue LPO
Gesamtübersicht “Kolloquiumsprogramm” im Sommersemester 2017