Glacial and periglacial deposits of the Tumbledown Cliffs area, James Ross Island, West Antarctica

Abstract

Investigations of the glacial geology of an ice-free area between local glaciers on western James Ross Island have shown that recent glaciation consists of small cirque glaciers and outlet glaciers from the central icefields. Erratics are evidence of an earlier, more widespread glaciation. Two till types are found in the area, a thin, erratic-bearing older diamicton interpreted as a lodgement till or a glaciotectonite and a younger, local till of supraglacial origin forming the recent terminal moraines. The present grounding line lies close to the sea level, resulting in subglacial deposition. A former more extended glacier was grounded further out in the Prins Gustav Channel. Frost action is intense in the cold, continental climate and large volumes of talus are produced. Rock glaciers are common, probably of both talus and glacier derived origin. The glacial and periglacial features, including a kame terrace and a raised beach, imply that the area has been ice-free throughout the Holocene and possibly longer.