Landforms of aeolian, tectonic and marine origin in the Bauer Bay-Sandy Bay region of subantarctic Macquarie Island

Abstract

Aeolian landforms on Macquarie lsland, in the Southern Ocean, occur above 100 m on the plateau between Bauer Bay and Sandy Bay. An extensive sand sheet, at least 6000 to 7000 years old, is wind and water eroded to produce blow-outs with bare troughs and vegetated elevated margins, Sand moved eastwards before the prevailing winds. Wind-polished bedrock on the western edge of the plateau is a relict feature. Wind-polishing of bedrock occurs today near sea level at the head of Bauer Bay. The area is tectonically active. No evidence of former glacial activity was observed. Topographic features in this area, previously regarded as glacial, are attributed to faulting. Tectonic uplift and sea-level changes are invoked to explain the formation and age of the broad and gently sloping raised marine terrace around much of the western and northern coasts. This explanation also sets constraints on the ages of the sand sheet and the cobble beach at about 100 m on the plateau east of Bauer Bay.