Reconstructing seasonal to millennial climatic changes in northern subtropical Africa during the Holocene: Relationships between precipitation, vegetation and erosion dynamics inferred from laminated sediments from the Nile deep-sea fan
Final Report Abstract
We used a unique sedimentary archive collected in 2008 on the submarine Nile delta, which contains fine laminations that correspond to annual flood deposits of early Holocene age. We aimed at reconstructing the changes in vegetation, erosion and runoff dynamics within the Nile watershed throughout the Holocene, and especially during the wet/dry transition of the African Humid Period termination. Such a reconstruction helps to understand the climate-environment relationships and the feedbacks between different components of the geosystem, and also helps understanding the humanenvironment relationships. Two main results were derived from our study: 1) although the overall Nile River runoff decreased steadily throughout the Holocene, the contribution from the two main sources (the Blue and White Niles) varied greatly and rapidly; 2) the vegetation cover and erosion pattern changed abruptly during the early Holocene, whereas the Nile Runoff remained high. The comparison of our reconstructions with published archeological reconstructions suggests that important steps of human evolution, such as the beginning of pastoralism, were probably triggered by rapid changes in the environment.
Publications
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2010. Active mud volcanoes on the upper slope of the western Nile deepsea fan – First results from the P362/2 cruise of R/V Poseidon. Geo-Marine Letters
Feseker, T., Brown, K., Blanchet, C.L., Scholz, F., Nuzzo, M., Reitz, A., Schmidt, M. & Hensen, C.
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«Response of vegetation and erosion dynamics to changes in precipitation in the Nile River drainage basin during the Holocene. Implications for the termination of the African Humid Period» XVIII INQUA Congress 2011, 21-27 July, Bern (Switzerland)
Blanchet, C.L., Lorenzen, J., Tjallingii, R., Schouten, S., Frank, M.
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“Response of vegetation and erosion dynamics to changes in precipitation in the Nile River drainage basin during the African Humid Period". Mineralogical Magazine 75 (3), p. 553 (2011). Goldschmidt General Assembly 2011, 14-19 August, Prag (Czech Republic)
Blanchet, C.L., Lorenzen, J., Tjallingii, R., Schouten, S., Frank, M.
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(2013) High- and low-latitude forcing of the Nile River regime during the Holocene inferred from laminated sediments of the Nile deep-sea fan. Earth and Planetary Science Letters 364, 98-110
Blanchet, C.L., Tjallingii, R., Frank, M. Lorenzen, J. Brown K., Feseker, T. and Brueckmann, W.
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(2014) Asynchrous changes in vegetation, runoff and erosion in the Nile River watershed during the Holocene. PLoSONE 9(12): e115958
Blanchet C.L., Frank, M. Schouten, S.
