Ice dolines on Larsen Ice Shelf, Antarctica

Abstract

Ice dolines on the Larsen Ice Shelf, Antarctica, are observed to be elongated depressions a few hundred meters across and up to 19 m deep. One-meter resolution imagery is used to quantify these dimensions. Elevation profiles across five dolines are derived by photoclinometry. Landsat and radar imagery is also used to show that dolines can form in a single melt season and persist for years. Dolines occur in clusters and in direct proximity to surface meltwater lakes. Field observations suggest dolines form by collapse into a subsurface cavity. A direct hydraulic connection with the underlying ocean is believed necessary to drain water that would otherwise collect in dolines. A formation hypothesis is discussed consistent with these observations and with energy-and hydrostatic-imbalance considerations.