The De Gerlache Seamounts actually consist of two medium-sized guyots, with summits at depths of 350-600 m. Acoustic profiler data show no significant sediment on these guyots. Alkaline basalts dredged from v the summit of the eastern guyot yield K/Ar ages between 20.1 ± 1.0 and 23.2 ± 1.2 Ma. Basement ridges and sediment-filled troughs between the guyots are associated with the prominent gravity anomaly extending north from the Antarctic margin. This structure possibly played a role in the guyot formation, however, the question of how the De Gerlache Seamounts are related to this gravity anomaly remains uncertain.