Large glacial boulders, up to several metres in diameter, resting on the la
ke ice are a remarkable feature of Lake Untersee (71 degrees 21'S, 13 degre
es 28'E), an ice-dammed, perennially frozen freshwater lake in the Ottovon-
Gruber-Gebirge (Gruber Mountains) of central Queen Maud Land, East Antarcti
ca. A geodetic survey of such ice-rafted boulders was made over two summer
seasons to determine the direction and velocity of their movement. They are
transported between 3.9 and 11.1 m annually and the residence time of the
boulders is estimated at approximately 500 years. Lake Untersee must have b
een permanently covered with lake ice for at least that long.