Abstract

Permian glacial sediments of the Pagoda Formation in the central Transantarctic Mountains range from 126 to 395 m in thickness. Grooved sandstone lenses within the tillite beds indicate that they were deposited during retreat phases from active temperate ice which flowed to the southeast. Several interbeds and sedimentary breaks within the formation suggest possibly as many as 13 minor advances and retreats of the ice front. Grooved surfaces and clast fabrics indicate that the ice moved across the area in a direction of 148° ± 19°. The paleo-ice flow directions vary randomly about the mean from bed to bed, probably in response to local conditions. Between ice advances, streams, some of them quite large, flowed across a subdued topography and were locally diverted or dammed by the retreating ice front.

The extent and continuity of the Paleozoic glacial deposits and the consistency in paleo-ice flow direction in Antarctica suggest an ice sheet of continental dimensions centered on southern Victoria Land. Dark shales conformably overlying the tillites over much of their known extent appear to have been deposited as the ice retreated prior to isostatic rebound of the depressed subglacial surface.

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