Cᵉ siècle av. J.-C. – XLᵉ siècle av. J.-C.
Chad Basin
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Pleistocene Lake Chad was a vast inland sea occupying the Chad Basin during wetter phases of the Pleistocene and Holocene. At its highest recorded stand, the ancestral lake reached 332 metres and covered approximately 400,000 square kilometres, leaving prominent shorelines. It later contracted during arid intervals before expanding again in the early Holocene.
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Le récit
The present Lake Chad is described as a remnant of a much larger inland sea that once filled the Chad Basin. The basin received water from the Central African savannahs, and its ancient lake left shorelines at elevations substantially above the modern lake. At the highest stand discussed, the lake reached 332 metres and occupied an estimated 400,000 square kilometres.
The lake’s size reflected a wetter regional climate despite substantial evaporation. At its greatest extent, evaporation may have been sixteen times greater than today, requiring annual inflow equivalent to one-third of the discharge of the Zaire. This hydrological balance makes the ancient lake evidence for increased precipitation in subhumid tropical latitudes.
The late Pleistocene and Holocene history included both expansion and desiccation. A lake stage in the upper Pleistocene was followed by aridity and extensive dune formation on the former lake plain. After a long interval of desiccation and aeolian activity, the lake began expanding shortly before 12,000 years before present, reached a maximum with intermittent overflows around 10,000 years ago, and remained high until about 4,000 years before present.
Cᵉ siècle av. J.-C. – XLᵉ siècle av. J.-C.
Chad Basin
Traduction non disponible · Original (anglais) · français indisponible
Pleistocene Lake Chad was a vast inland sea occupying the Chad Basin during wetter phases of the Pleistocene and Holocene. At its highest recorded stand, the ancestral lake reached 332 metres and covered approximately 400,000 square kilometres, leaving prominent shorelines. It later contracted during arid intervals before expanding again in the early Holocene.
Poursuivre l’exploration
Le récit
The present Lake Chad is described as a remnant of a much larger inland sea that once filled the Chad Basin. The basin received water from the Central African savannahs, and its ancient lake left shorelines at elevations substantially above the modern lake. At the highest stand discussed, the lake reached 332 metres and occupied an estimated 400,000 square kilometres.
The lake’s size reflected a wetter regional climate despite substantial evaporation. At its greatest extent, evaporation may have been sixteen times greater than today, requiring annual inflow equivalent to one-third of the discharge of the Zaire. This hydrological balance makes the ancient lake evidence for increased precipitation in subhumid tropical latitudes.
The late Pleistocene and Holocene history included both expansion and desiccation. A lake stage in the upper Pleistocene was followed by aridity and extensive dune formation on the former lake plain. After a long interval of desiccation and aeolian activity, the lake began expanding shortly before 12,000 years before present, reached a maximum with intermittent overflows around 10,000 years ago, and remained high until about 4,000 years before present.
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