Some observations on the formation of an active pronival rampart at Grunehogna Peaks, Western Dronning Maud Land, Antarctica

Abstract

Summer observations of the morphology and the debris accumulation processes at an actively forming pronival rampart at Grunehogna Peaks, Western Dronning Maud Land, Antarctica demonstrate that rockfall debris accumulation is causing downslope (outward) rampart extension even though the distal slope is not at the angle of repose. Field experiments show that the vast majority of rocks can traverse a stable firn surface to reach the proximal slope of the rampart and more than half end up on the distal slope or beyond. The formation processes indicate that the morphological characteristics and environmental conditions under which such features develop may be more varied than conceived in current models. Consequently, caution must be employed when fossil ramparts are used to infer palaeo-environmental conditions.