Project Details
Projekt
Late Quaternary climate and environmental reconstruction based on lake and peat sediments from the central southern Cape region of South Africa
Subject Area
Physical Geography
Term
since 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 434918595
The aim of this project is to gain new knowledge on the Late Quaternary paleoenvironmental development of southern Africa. For this purpose, a multi-proxy approach including (bio-)geochemical methods will be applied to peat and lake sediments investigating the Holocene and Marine Isotope Stage (MIS) 3.Due to the scarcity of archives for paleoenvironmental studies, the climatic and environmental evolution of South Africa during the Late Quaternary has been highly debated. Coastal lakes and wetlands which are excellent geoarchives to reconstruct past environmental change are available only occasionally. However, such systems often provide records which are either discontinuous, confined to specific periods or of coarse resolution.To improve this situation, sediment cores from two geoarchives (Vankervelsvlei and Voelvlei) located in the central southern Cape region of South Africa were recovered within the RAiN project (Regional Archives for Integrated iNvestigations). Based on investigations within this project it is hypothesized that paleoenvironmental conditions influencing the climate of the proposed study sites were much more dynamic during the past than it has been hitherto expected. In order to test this hypothesis further paleoenvironmental studies on local archives are urgently needed. In response to that need, we suggest a high-resolution, quantitative climatic reconstruction using a multi-proxy approach on the recovered sediment sequences from the Vankervelsvlei fen and the Voelvlei lake in this proposal, including investigations of parameters impacting the climate system which hitherto have never been investigated before, e.g., evaporation.Vankervelsvlei is located at the southern Cape coast of South Africa at 152 m a.s.l. A 14.6 m long sediment sequence was retrieved and preliminary investigations point out its enormous potential for paleoenvironmental reconstruction for the Holocene and MIS 3. Voelvlei located 100 km to the southwest of Vankervelsvlei will be used as archive for comparison, to differentiate between regional climate signals and local overprints.Both archives will be investigated using identical methods, allowing a high-resolution reconstruction of paleoenvironmental variability. Quantitative multi-element analyses and particle size distributions will be used to reconstruct relative changes in paleoprecipitation and wind intensity. To quantify precipitation, evaporation and relative humidity, a coupling of leaf wax stable hydrogen isotopes with stable oxygen isotopes of plant-derived sugars will be applied. Leaf wax stable carbon isotopes and CN analyses will be used to explore changes in the vegetation composition. To ensure robust paleoclimatic interpretations, analyses on recent plant and topsoil material will be compared to surface samples of Vankervelsvlei and Voelvlei to understand signal transformation processes from source to sink and to ensure more robust interpretations of paleoenvironmental conditions.
DFG Programme
Research Grants
Cooperation Partners
Professor Dr. Bruno Glaser; Dr. Thomas Kasper; Professor Dr. Michael Zech
