Reconstruction of Megalake Chad using Shuttle Radar Topographic Mission data

Leblanc, Marc; Favreau, Guillaume; Maley, Jean; Nazoumou, Yahaya; Leduc, Christian; Stagnitti, Frank; Oevelen, P.J. van; Dagognet, François; Lemoalle, Jacques

doi:10.1016/j.palaeo.2006.01.003

Cited by 91 publications

(68 citation statements)

References 20 publications

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“…The sedimentary evidence for these old Egyptian lakes is less compelling than that of the newly defi ned mega-Lake Chad (Leblanc et al, 2006), the Northern Darfur Megalake in northwestern Sudan (Hoelzmann et al, 2001), the White Nile lake in central Sudan (Williams et al, 2010), or Lake Megafazzan in Libya (Drake et al, 2008). Nonetheless, the topographic data add to the growing evidence for numerous early and middle Pleistocene lakes across North Africa that could have supported human migration patterns.…”

Section: Discussionmentioning

confidence: 88%

Evidence for Pleistocene lakes in the Tushka region, south Egypt

Maxwell

Issawi²,

Haynes

2010

Geology

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Section: Discussionmentioning

confidence: 88%

Evidence for Pleistocene lakes in the Tushka region, south Egypt

Maxwell

Issawi²,

Haynes

2010

Geology

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“…2005, 2009Drake and Bristow, 2006;Leblanc et al, 2006;Bouchette et al, 2010). At the time, this large water body reached more than 350 000 km 2 (Ghienne et al, 2002;Schuster et al, 2005;Leblanc et al, 2006) with wind-driven hydrodynamics (Bouchette et al, 2010). Similar MLC episodes are thought to have occurred during the Miocene and the Pliocene (Schuster et al, 2001(Schuster et al, , 2006Griffin, 2006), supposedly linked to a northward shift of the West African monsoon system.…”

mentioning

confidence: 80%

“…The black contour line represents the Chad hydrological basin (catchment) limits. 2005, 2009Drake and Bristow, 2006;Leblanc et al, 2006;Bouchette et al, 2010). At the time, this large water body reached more than 350 000 km 2 (Ghienne et al, 2002;Schuster et al, 2005;Leblanc et al, 2006) with wind-driven hydrodynamics (Bouchette et al, 2010).…”

mentioning

confidence: 97%

Megalake Chad impact on climate and vegetation during the late Pliocene and the mid-Holocene

et al. 2013

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Given the growing evidence for megalakes in the geological record, assessing their impact on climate and vegetation is important for the validation of palaeoclimate simulations and therefore the accuracy of model–data comparison in lacustrine environments. Megalake Chad (MLC) occurrences are documented not only for the mid-Holocene but also for the Mio-Pliocene (Schuster et al., 2009). At this time, the surface covered by water would have reached up to ~350 000 km² (Ghienne et al., 2002; Schuster et al., 2005; Leblanc et al., 2006), making it an important evaporation source, possibly modifying climate and vegetation in the Chad Basin. We investigated the impact of such a giant continental water area in two different climatic backgrounds within the Paleoclimate Model Intercomparison Project phase 3 (PMIP3): the late Pliocene (3.3 to 3 Ma, i.e. the mid-Piacenzian warm period) and the mid-Holocene (6 kyr BP). In all simulations including MLC, precipitation is drastically reduced above the lake surface because deep convection is inhibited by overlying colder air. Meanwhile, convective activity is enhanced around MLC because of the wind increase generated by the flat surface of the megalake, transporting colder and moister air towards the eastern shore of the lake. The effect of MLC on precipitation and temperature is not sufficient to widely impact vegetation patterns. Nevertheless, tropical savanna is present in the Chad Basin in all climatic configurations, even without MLC presence, showing that the climate itself is the driver of favourable environments for sustainable hominid habitats

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“…Because of greater inclination of the Earth's axis to the Sun, the Intertropical Convergence Zone (ITCZ) was displaced in the summer more toward the pole of the summer hemisphere. The African monsoon, blowing off the Gulf of Guinea, reached further north, resulting in elevated groundwater level in the Lake Chad basin, whose surface during the maximum range was comparable to today's Germany, and drained into the Atlantic [21]. Additionally, equatorial easterly winds blowing over Africa, related to the Walker circulation, were also stronger as evidenced by the high water levels of great lakes in East Africa, with maximum from 15.3 to 11.5 thousand years ago [22].…”

Section: The Holocene Climatic Optimum (Hco)mentioning

confidence: 99%

Was the 4.2 ka Event an Anthropogenic Disaster?

Szczęsny¹

2016

OJE

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The article describes a possible impact of demographic explosion during the Neolith on local ecosystems and on the global climate as well as the role of this explosion in aggravating the course of 4.2 ka cooling event. A possible role of human activity in changing the pattern of mid-latitudes westerlies, monsoons and Walker circulation throughout the Holocene is analyzed. It is explained why during the Holocene Climatic Optimum (HCO) monsoons could have been weaker than today, not stronger, as it is commonly stated. It is described how during the HCO the humid Tibetan Plateau could have repelled the Indian monsoon to the west and the East Asian monsoon to the north. The explanation for weaker El Niño-Southern Oscillation (ENSO) during HCO is proposed.

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Reconstruction of Megalake Chad using Shuttle Radar Topographic Mission data

Cited by 91 publications

References 20 publications

Evidence for Pleistocene lakes in the Tushka region, south Egypt

Evidence for Pleistocene lakes in the Tushka region, south Egypt

Megalake Chad impact on climate and vegetation during the late Pliocene and the mid-Holocene

Was the 4.2 ka Event an Anthropogenic Disaster?

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