A multiproxy study of the ocean-atmospheric forcing and the impact of sea-level changes on the southern Cape coast, South Africa during the Holocene

Kelly L. Kirsten, Torsten Haberzettl, Michael Wündsch, Peter Frenzel, Stephanie Meschner, A.J. Smit, Lynne J. Quick, Roland Mäusbacher, Michael E. Meadows

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

A multiproxy approach, focusing on biological proxies, was undertaken to determine the influence of sea-level changes along the southern Cape coast and the variability of water masses over the central Agulhas Bank region during the Holocene. A 30.47 m sedimentary core extracted from the coastal lake, Eilandvlei, shows continuous deposition for the last 9000 years. Microfossils were classified based on salinity and habitat, diatoms were further defined by their temperature preferences as either warm- or cold-water species. The composition of the assemblages is strongly linked to fluctuations in marine inflow into the system and the extent of freshwater inputs to the lake as recorded at the core site. Paleoproductivity improved during periods of equatorward migration of the westerlies, notably from 5800 to 5000 cal yr B.P., when surface water mixing increased. Spectral analysis revealed periodicities associated with solar cycles, namely Gleissberg and De Vries. The system remained predominantly marine and submerged in response to an early-mid Holocene transgression until 4700 cal yr B.P., when sea-level fluctuations and landscape modification restricted marine incursions, modified the exposed landscape and shifted the system toward a lagoon state. This multiproxy record provides insights into oceanic exchanges, surface water conditions and the mechanisms that govern them during the Holocene.
Original languageEnglish
Pages (from-to)282-291
Number of pages10
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume496
Early online date2 Feb 2018
DOIs
Publication statusPublished - 1 May 2018
Externally publishedYes

Bibliographical note

© 2018 Elsevier B.V. All rights reserved

Funder

We thank the two anonymous reviewers for their comments, which improved the manuscript. This study was funded by the German Federal Ministry of Education and Research (BMBF) (Fund no. 03G0862B). The investigations were conducted within the collaborative project “Regional Archives for Integrated Investigations” (RAIN), which is embedded in the international research programme SPACES (Science Partnership for the Assessment of Complex Earth System Processes). KLK would like to acknowledge the funding received from the Deutscher Akademischer Austauschdienst (DAAD) SPACES Scholarship (Fund no. 54654772) for Short Time Research in Germany. Gratitude is extended to SANParks Scientific Services, Rondevlei, for logistic support and permission to work in the park. The authors would like to thank Neil Malan for helpful discussions during the writing process.

Keywords

  • Southern westerly winds
  • Bacillariophyceae
  • Ostracoda
  • Foraminifera
  • Spectral analysis
  • Agulhas system

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