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| Titel |
The Lower Molopo River super site (SW Kalahari) and its relevance for the analysis of supra-regional Late Quaternary climate and land-use changes in Southern Africa |
| VerfasserIn |
Jennifer Winkelbauer, Jörg Völkel, Oliver Bens, Klaus Heine |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080390
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| Zusammenfassung |
| The semi-arid to semi-humid Kalahari of southern Africa is a region with enormous climatic
fluctuations due to recent and former shifting of tropical and subtropical atmospheric
circulation patterns and changing climatic factors. Although it is clear that large, rapid
temperature changes have occurred during the Late Quaternary, we have only limited, and
often imprecise, knowledge of how the major moisture-bearing atmospheric circulation
systems have reacted to these changes. During the Last Glacial Maximum (LGM) a transition
zone existed at approximately 24Ë S that was characterized by the overlap of alternating
tropical summer rain in the north (ITCZ) and subtropical winter rain (Westerlies)
in the south. As part of this transition zone, the study area of the Lower Molopo
River valley (20-21Ë E and 26Ë 45’-28Ë 40’S) offers ideal conditions for terrestrial
research on Late Quaternary paleoclimate and environmental changes. Here dunes,
pans, slopes and river terraces coexist as major geomorphological types in an ideal
way, including different fluvial sediment facies interbedded with slope and eolian
sediments, as well as the confluence of the Molopo and Orange River systems. Such
geoarchives are typically modified by climatic fluctuations and changes. To assess
the paleoclimatic information in time and space, physico-chemical parameters of
the sediment archives must be determined to clearly characterize single sediment
types and their spatial interrelation. Particularly the interpretation of stratigraphical
interbeddings of different sediment facies delivers types, directions or intensities of
alternating processes. The sedimentological analysis is systematically combined with
OSL- and 14C-dating techniques. The results of our analysis on dune development
and fluvial activity comprehensively clarify the chronology of significant shifts in
Late Quaternary river regimes, rainfall inputs and atmospheric circulation patterns
(Hürkamp et al. 2011) and will be intensified by further geoarchive prospection. As
such, the project delivers a very valuable input to the interdisciplinary analysis of
past and future global change in the highly sensitive environments of Southern
Africa.
Hürkamp, K., Völkel, J., Heine, K., Bens, O., Leopold, M. & J. Winkelbauer (2011): Late
Quaternary Environmental Changes from Aeolian and Fluvial Geoarchives in the
Southwestern Kalahari, South Africa: Implications for Past African Climate Dynamics. -
South African Journal of Geology, 114 (2). |
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