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| Titel |
Kalahari salt pans as sedimentary archives for reconstruction of Quaternary environments |
| VerfasserIn |
Irka Schüller, Lukas Belz, Heinz Wilkes, Achim Wehrmann |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102870
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| Publikation (Nr.) |
 EGU/EGU2015-2273.pdf |
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| Zusammenfassung |
| Environmental changes in southern Africa come along with variations in atmospheric and
oceanic circulation as well as anthropogenic caused landuse changes. The reconstruction
of the paleoenvironment is complicated by the fact that continuous geoarchives
are rare in the semiarid to arid parts of this region. In the south-western Kalahari
lacustrine systems with constant sedimentary records are absent due to the low
precipitation. Salt pans are common geomorphological structures in the Kalahari which are
temporarily flooded during summer season when isolated showers occur in their local
catchment area. So, they are potential archives preserving environmental signals in
phases of sedimentation. However, marginal dunes on their leeward sides represent
phases of deflation. The principle processes in salt pan formation are complex and so
far under discussion. Our study follows a multidisciplinary approach integrating
sedimentological, geochemical and microbiological methods to understand the formation of
salt pans as a prerequisite for using them as geoarchives in reconstruction of the
paleoenvironmental condition during phases of sedimentation and erosion. Sediment
cores from five salt pans were analysed using XRD, XRF and grain size analyses.
Additionally, age models can be given for four salt pans, based on δ14C from bulk
sediment TOC. As palynological material is lacking, different methods in organic
geochemistry were applied (plant biomarkers, particularly leaf wax n-alkanes and
n-alcohols and their stable carbon and hydrogen isotopic signatures) to reconstruct
variations in local vegetation assemblages. Our results allow a better understanding of
the sedimentology of salt pans and their interpretation as discontinuous archives. |
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