Late Quaternary highstands at Lake Chilwa,Malawi: Frequency,timing and possible forcing mechanisms in the last 44 ka |
| |
| Authors: | David SG Thomas Richard Bailey Paul A Shaw Julie A Durcan Joy S Singarayer |
| |
| Institution: | 1. School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK;2. Department of Environmental and Geographical Science, University of Cape Town, Rondebosch 7701, South Africa;3. Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DB, UK;4. Department of Geography, University of the West Indies, St Augustine, Trinidad and Tobago;5. School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK;1. IRAMAT-CRP2A, UMR 5060, CNRS - Université Bordeaux Montaigne, Pessac, Cedex, France;2. Australian Research Centre for Human Evolution (ARCHE), Environmental Futures Research Institute (EFRI), Nathan, QLD, 4111, Australia;3. Geochronology, Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain;4. Institute of Geography, University of Cologne, Cologne, Germany;5. Inrap, Bègles, France;6. PACEA, UMR 5199, CNRS - Université de Bordeaux, Pessac, Cedex, France;7. EPOC – OASU, UMR 5805, CNRS - Université de Bordeaux, Pessac, Cedex, France;8. AUSONIUS, UMR 5607, CNRS - Université Bordeaux Montaigne, Pessac, Cedex, France;1. Department of Geological Sciences, Brown University, Box 1846, Providence, RI 02912, USA;2. Institute of Geography and Earth Sciences, University of Wales, Aberystwyth SY23 3DB, UK;3. Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, USA;4. School of Earth & Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0340, USA;1. School of Geography and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, UK;2. Department of Environmental and Geographical Science, University of Cape Town, Rondebosch 7701, South Africa;1. Department of Geological Sciences, Brown University, Box 1846, Providence, RI, 02912, USA;2. Department of Atmospheric and Environmental Sciences, University at Albany, SUNY, 1400 Washington Ave., Albany, NY, 12222, USA;3. Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Telegrafenberg A43, 14463, Potsdam, Germany |
| |
| Abstract: | The extensive shoreline deposits of Lake Chilwa, southern Malawi, a shallow water body today covering 600 km2 of a basin of 7500 km2, are investigated for their record of late Quaternary highstands. OSL dating, applied to 36 samples from five sediment cores from the northern and western marginal sand ridges, reveal a highstand record spanning 44 ka. Using two different grouping methods, highstand phases are identified at 43.7–33.3 ka, 26.2–21.0 ka and 17.9–12.0 ka (total error method) or 38.4–35.5 ka, 24.3–22.3 ka, 16.2–15.1 ka and 13.5–12.7 ka (Finite Mixture Model age components) with two further discrete events recorded at 11.01 ± 0.76 ka and 8.52 ± 0.56 ka. Highstands are comparable to the timing of wet phases from other basins in East and southern Africa, demonstrating wet conditions in the region before the LGM, which was dry, and a wet Lateglacial, which commenced earlier in the southern compared to northern hemisphere in East Africa. We find no evidence that wet phases are insolation driven, but analysis of the dataset and GCM modelling experiments suggest that Heinrich events may be associated with enhanced monsoon activity in East Africa in both timing and as a possible causal mechanism. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
