Burdanowitz, Nicole; Dupont, Lydie M; Zabel, Matthias; Schefuß, Enno (2017): n-Alkanes and compound-specific isotopes in the Orange River system. PANGAEA, https://doi.org/10.1594/PANGAEA.873759, Supplement to: Burdanowitz, N et al. (2018): Holocene hydrologic and vegetation developments in the Orange River catchment (South Africa) and their controls. The Holocene, 28(8), 1288-1300, https://doi.org/10.1177/0959683618771484
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The summer rainfall zone (SRZ) in the South African interior experienced pronounced hydrological and vegetation changes during the Holocene inferred to be driven mainly by shifts in atmospheric and oceanic circulations systems. The exact mechanisms controlling these changes are still debated. To gain better insights into the Holocene environmental changes in the South African SRZ and their driving factors, we analysed compound-specific carbon and hydrogen isotopes of plant wax n-alkanes (δ13Cwax and δDwax) from a marine sediment core covering the last 9900 years. The core has been recovered offshore the mouth of the Orange River, predominantly draining the South African summer rainfall region. Our data indicate a dry early Holocene and a gradual increase of wetter conditions with a higher abundance of C4 vegetation towards the middle Holocene. Wettest conditions occurred around 3900 cal. yr BP. The last 3900 years were characterised by a gradual aridification overlain by variable wetter conditions. During the 'Little Ice Age' (LIA: ca. 640–310 cal. yr BP), relatively dry conditions with elevated C4 plant contributions occurred. This opposite behaviour, that is, more C4 plant contribution during drier conditions compared to the remainder of the Holocene, points towards an influence of winter rainfall in the lower Orange River catchment during the late-Holocene and a decline in summer rainfall. We emphasise the importance of changes in the latitudinal insolation gradient (LIG) as a potentially important controlling mechanism for hydrologic and vegetation changes in the SRZ.
Median Latitude: -29.551844 * Median Longitude: 18.130361 * South-bound Latitude: -32.495667 * West-bound Longitude: 16.504783 * North-bound Latitude: -28.092817 * East-bound Longitude: 23.740800
Date/Time Start: 2003-01-28T18:50:00 * Date/Time End: 2003-01-31T12:50:00
Datasets listed in this publication series
- Burdanowitz, N; Dupont, LM; Zabel, M et al. (2017): Lipid biomarker of sediment core GeoB8331-4. https://doi.org/10.1594/PANGAEA.873743
- Burdanowitz, N; Dupont, LM; Zabel, M et al. (2017): Lipid biomarkers of samples from the Orange River, South Africa. https://doi.org/10.1594/PANGAEA.873758
- Burdanowitz, N; Dupont, LM; Zabel, M et al. (2017): n-alkane deuterium analyses of surface sediment samples. https://doi.org/10.1594/PANGAEA.873756