Hydrodynamics in Holocene Lake Mega-Chad

Bouchette, Frédéric; Schuster, Mathieu; Ghienne, Jean‐François; Denamiel, Cléa; Roquin, Claude; Abderamane, Moussa; Marsaleix, Parttick; Duringer, Philippe

doi:10.1016/j.yqres.2009.10.010

Cited by 50 publications

(36 citation statements)

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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.…”

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confidence: 79%

“…Morphosedimentary archives indicate an active Holocene hydrographic system flowing from the east (south Ennedi) associated with small-scale palaeodeltas which argue for riverine and lacustrine conditions (Ghienne et al, 2002;Schuster et al, 2005;Bouchette et al, 2010). For the Mio-Pliocene, fluvial deposits of the Koro-Toro, Kossom Bougoudi and Kollé sites are attributed to ephemeral floods (Schuster, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…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).…”

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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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confidence: 79%

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confidence: 99%

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

et al. 2013

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“…Most of the information about the area south of the Sahara and its people had been gathered various animal species across the Sahara during humid periods (Drake et al, 2011). The most important climatic changes have been documented for the Early Holocene starting ∼12 ka, when the giant 350,000-km 2 Lake Mega-Chadthe largest late Pleistocene water body in Africa-was formed (Schuster et al, 2005;Leblanc et al, 2006;Bouchette et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

The Genetic Impact of the Lake Chad Basin Population in North Africa as Documented by Mitochondrial Diversity and Internal Variation of the L3e5 Haplogroup

Podgorná

Soares

Pereira

et al. 2013

Annals of Human Genetics

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SummaryThe presence of sub‐Saharan L‐type mtDNA sequences in North Africa has traditionally been explained by the recent slave trade. However, gene flow between sub‐Saharan and northern African populations would also have been made possible earlier through the greening of the Sahara resulting from Early Holocene climatic improvement. In this article, we examine human dispersals across the Sahara through the analysis of the sub‐Saharan mtDNA haplogroup L3e5, which is not only commonly found in the Lake Chad Basin (∼17%), but which also attains nonnegligible frequencies (∼10%) in some Northwestern African populations. Age estimates point to its origin ∼10 ka, probably directly in the Lake Chad Basin, where the clade occurs across linguistic boundaries. The virtual absence of this specific haplogroup in Daza from Northern Chad and all West African populations suggests that its migration took place elsewhere, perhaps through Northern Niger. Interestingly, independent confirmation of Early Holocene contacts between North Africa and the Lake Chad Basin have been provided by craniofacial data from Central Niger, supporting our suggestion that the Early Holocene offered a suitable climatic window for genetic exchanges between North and sub‐Saharan Africa. In view of its younger founder age in North Africa, the discontinuous distribution of L3e5 was probably caused by the Middle Holocene re‐expansion of the Sahara desert, disrupting the clade's original continuous spread.

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“…The lake was therefore equivalent in surface area to the Caspian Sea, in surface area the largest lake that exists on earth today. In the northern section, LMC reached an approximate depth of at least 150 m; in its southern part, around 40 m. 21 The desiccation and decrease of LMC can be dated to the third millennium bce, between 5280 and 4410 cal. b.p.…”

Section: T C P ( ) T S Mmentioning

confidence: 99%

The West Beyond the West: The Mysterious “Wernes” of the Egyptian Underworld and the Chad Palaeolake

Schneider

2011

Journal of Ancient Egyptian Interconnections

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Amduat, one of the Egyptian guides to the underworld, provides specific descriptions and measurements relating to the ﬁrst three hours after sunset, during which the sun god Re passes through an interstitial realm (the ﬁrst hour) before arriving at two gigantic sweet-water oceans (the second and third hours). Rather than seeing in this imagery reﬂections of the unconscious and antecedents of modern psychotherapy (as has been proposed by some modern scholars), the present work argues that the description was inspired by actual knowledge of the environment of the region to the distant southwest of the Nile Valley, beyond the Gilf Kebir and Gebel Uweinat on modern Egypt’s southwest corner. Recent evidence has made plausible that the Abu Ballas Trail connected Egypt with the Chad Basin of Central Africa. Elements of the factual description provided in the Amduat (including environmental and linguistic details; e.g., the hitherto unexplained name “Wernes”) can be corroborated by modern palaeoecological reconstruction of the area as having comprised gigantic palaeolakes, as well as by linguistic and narrative evidence.

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Hydrodynamics in Holocene Lake Mega-Chad

Cited by 50 publications

References 39 publications

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

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

The Genetic Impact of the Lake Chad Basin Population in North Africa as Documented by Mitochondrial Diversity and Internal Variation of the L3e5 Haplogroup

The West Beyond the West: The Mysterious “Wernes” of the Egyptian Underworld and the Chad Palaeolake

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