Climate Signals from the Sedimentary Record

Sedimentary strata of Eocene and Oligocene age are exposed in the Antarctic Peninsula region and provide an important record of environmental conditions on land and in shallow marine settings during this period. In addition, there are intriguing hints about environments at higher latitudes, extracted from erratic boulders composed of Eocene and Oligocene fossiliferous sediments in the Ross Sea region, derived from sub-glacial outcrops. A summary of the important outcrops and their environmental signal is given below.

Sedimentary rocks of Palaeogene age are exposed around the northern part of the Antarctic Peninsula, on the South Shetland Islands and on Seymour Island (Fig. 8.1). The sediments were deposited in very different tectonic settings and environments - the South Shetland sequence is of terrestrial volcanic and sedimentary deposits that represent an outer-arc (Birkenmajer, 1995) or fore-arc (Elliot, 1988) succession; the sequence on Seymour Island consists of marine clastics deposited in a back-arc basin, the uppermost beds of a regressive megasequence (Hathway, 2000). Both contain evidence of Palaeogene cooling and the first appearance of ice but in different settings.

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