Geomorphology - Where glaciers cut deep

摘要

Of all elevated continental margins, only those repeatedly covered by Quaternary ice sheets display fj ords (Fig. 1). Th ese dramatic features include steep-sided and ocean-terminating valleys with basins that extend kilometres below sea level. Th e process of selective linear erosion1, in which local variations in basal temperature and presence of water lead to distinct corridors of erosion, is well established. It is also widely understood that strong feedback mechanisms must be in operation to allow highly localized erosion to grind into resistant rock types at such great depths. However, the precise nature of these feedbacks has remained elusive, and the complexity of glacial erosion processes has greatly discouraged serious attempts to numerically model fj ord formation. On the Nature Geoscience website today, Kessler and co-authors2 come up with a surprisingly elegant concept for fj ord formation by avoiding this complexity through the use of a relatively simple model.