Abstract
Recent geophysical mapping of the Arctic seafloor has revealed extensive erosion caused by ice and glacial landforms on ridge crests and plateaus where present water depths are shallower than . Such erosion stems from thick outlet glaciers and massive ice shelf complexes. Cores and glacigenic landforms suggest that the largest ice shelf complex was confined to the Amerasian sector of the Arctic Ocean, roughly 135,000 years ago. We apply a peak over threshold approach to assess whether the calving fronts of this ice shelf complex comprise a likely source of the deep draft icebergs responsible for the mapped plow marks. This approach is novel to modeling Arctic paleoglacial configurations. Predicted extreme calving front drafts match observed deep-draft iceberg marks if the ice shelf complex is sufficiently large. We explain the methodology of Kirchner, Furrer, Jakobsson and coauthors [1] in a storyboard framework, i.e., with figures and sketches. Here, we extend their approach by using shelf specific threshold selection, an alternative estimate to scale ‘coastlines’, supervised pooling of estimates and uncertainty estimates based on parametric bootstrap. For theoretical details as well as details about the precise origin and preprocessing of the data we refer to [1], much of the statistical theory is covered in [2, 2].
Furrer, Reinhard