Northwest African biomes and climate variability during the Pliocene
Final Report Abstract
To provide deeper insights into the development of climate and vegetation in West Africa during the Pliocene (~5-2.5 Ma) and the possible effects of ocean circulation, we conducted a combined pollen-biomarker study on well-dated continuous marine archives from the tropical northeast Atlantic. It turned out that West Africa was generally wetter during the Pliocene than during the last glacial cycle and that aridity changes were driven by an interplay of local insolation and the latitudinal temperature gradient (depending on orbital configuration) and that effects of Atlantic deep water circulation on vegetation and climate were still small during the Pliocene. This changed with the growth of the ice-sheets on the Northern Hemisphere since 2.7 Ma; NE trade winds became stronger and the influence of North Atlantic sea surface temperatures on West African climate increased. During the early Pliocene (~5-4.5 Ma) arid spells occurred less frequently in West Africa. Savannahs already existed, but changed in composition around 3.0 Ma and contained more woody elements in the Pliocene than in the late Pleistocene (past 0.15 Ma). Due to an exceptional orbital configuration, a prolonged humid period occurred between 3.24 and 3.20 Ma.
Publications
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2013. NW African hydrology and vegetation during the Last Glacial cycle reflected in plant-wax-specific hydrogen and carbon isotopes. Quaternary Science Reviews 82, 56-67
Kuechler, R.R., Schefuß, E., Beckmann, B., Dupont, L.M., Wefer, G.
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Pliocene environmental change in West Africa and the onset of strong NE trade winds (ODP Sites 659 and 658). Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 414. 2014, pp. 403–414.
Vallé, F., Dupont, L.M., Leroy, S.A.G., Schefuß, E., Wefer, G.
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Hybrid insolation forcing of Pliocene monsoon dynamics in West Africa. Clim. Past, Vol 14 Issue 1, 73-84, 2018
Kuechler, R.R., Dupont, L.M., Wefer, G., Schefuß, E.
