Glacial Sediment–Landform Associations and Paleoclimate during the Last Glaciation, Strait of Magellan, Chile
Glacial sediments and landforms preserved beside the Strait of Magellan record repeated advances of an outlet of the Patagonian Icefield during and following the last glacial maximum (LGM; ∼25,000–14,000 14 C yr B.P.). Ice-marginal landform assemblages consist of thrust moraine complexes, kame and k...
Published in: | Quaternary Research |
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Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
2000
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Subjects: | |
Online Access: | http://dx.doi.org/10.1006/qres.2000.2140 http://api.elsevier.com/content/article/PII:S0033589400921409?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589400921409?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400026089 |
Summary: | Glacial sediments and landforms preserved beside the Strait of Magellan record repeated advances of an outlet of the Patagonian Icefield during and following the last glacial maximum (LGM; ∼25,000–14,000 14 C yr B.P.). Ice-marginal landform assemblages consist of thrust moraine complexes, kame and kettle topography, and lateral meltwater channels, very similar to those found at the margins of modern subpolar glaciers. Taken together with other forms of paleoenvironmental evidence, the landform assemblages show that, during the LGM and late-glacial time, permafrost occurred near sea level in southernmost South America. This finding implies that mean annual temperatures were ∼7–8°C lower than at present, somewhat lower than those reconstructed by current glacier–climatic models. Comparison with precipitation–temperature relationships for modern glaciers suggests, in addition, that precipitation levels were lower than today. Reduced glacial-age precipitation may have resulted from a precipitation shadow induced by the Patagonian Icefield, an equatorward migration of the average position of westerly cyclonic storm tracks in the southern midlatitudes, or both these factors. |
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