Ice-cored drumlins at the surge-type glacier Bruarjokull, Iceland: a transitional-state landform

摘要

This paper presents data on a glacial landform that, to Our knowledge, has not previously been described in the literature: the ice-cored drumlin. The study area is the forefield of the surge-type glacier Bruarjokull at the northeastern margin of the Vatnajokull ice cap, Fast Iceland. Based on sedimentological field investigations and aerial photograph interpretation, a qualitative model for the formation of ice-cored drumlins is proposed. The drumlin core consists of stagnant glacier ice from a previous advance and bubbly ice formed by snowdrifts, which were incorporated during the most recent advance-the 1963-64 surge. This advance deposited a mantle of basal till and streamlined the ice-cored moraines. Till deformation and deposition on the drumlin ice-core is facilitated by a substratum of low-permeability ice-cored moraines.