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The last interglacial sea-level high stand on the southern Cape coastline of South Africa |
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| Authors: | Andrew S Carr Mark D Bateman Colin V Murray-Wallace Peter J Holmes |
| Institution: | a Department of Geography, University of Leicester, University Road, Leicester LE1 7RH, UK b Sheffield Centre for International Drylands Research, Department of Geography, University of Sheffield, Winter Street, Sheffield, S10 2TN, UK c Council for Geoscience, PO Box 572, Bellville 7535, South Africa d GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, NSW, 2522, Australia e Department of Geography, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa |
| Abstract: | The continental margin of southern South Africa exhibits an array of emergent marginal marine sediments permitting the reconstruction of long-term eustatic sea-level changes. We report a suite of optical luminescence ages and supplementary amino acid racemization data, which provide paleosea-level index points for three sites on this coastline. Deposits in the Swartvlei and Groot Brak estuaries display tidal inlet facies overlain by shoreface or eolian facies. Contemporary facies relations suggest a probable high stand 6.0-8.5 m above modern sea level (amsl). At Cape Agulhas, evidence of a past sea-level high stand comprises a gravel beach (ca. 3.8 m amsl) and an overlying sandy shoreface facies (up to 7.5 m amsl). OSL ages between 138 ± 7 ka and 118 ± 7 ka confirm a last interglacial age for all marginal marine facies. The high stand was followed by a sea-level regression that was associated with the accumulation of eolian dunes dating to between 122 ± 7 ka and 113 ± 6 ka. These data provide the first rigorous numerical age constraints for last interglacial sea-level fluctuations in this region, revealing the timing and elevation of the last interglacial high stand to broadly mirror a number of other far-field locations. |
| Keywords: | Sea-level Marine Isotope Stage 5e Luminescence dating South Africa Quaternary Eolianite |
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