Cᵉ siècle av. J.-C.
Equatorial East Africa, Ethiopian Highlands, Atlas Mountains
Traduction non disponible · Original (anglais) · français indisponible
Pleistocene African glaciation affected high mountain regions, especially in equatorial East Africa and the Ethiopian highlands, while the Atlas Mountains formed the principal exception outside East Africa. Former glaciers descended far below modern snowlines on Mount Kenya, Mount Kilimanjaro, Mount Elgon, Mount Ruwenzori, and several Ethiopian peaks. The excerpt concludes that equatorial and sub-equatorial Africa was glaciated at least twice and was especially cool during the Würm.
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Le récit
Former African glaciation was concentrated in highlands, with nearly all known glaciated areas located in East Africa within a few degrees of the equator, apart from the Atlas Mountains. The elevations of these mountains range from roughly 3,900 to 6,100 metres. Snowfall nourishing the glaciers is attributed mainly to orographic precipitation carried by maritime air masses from the South Atlantic and, to a lesser extent, the Indian Ocean.
The evidence records dramatic differences between Pleistocene and modern snowlines. Mount Kenya’s Pleistocene snowline is estimated at 900 metres, compared with a present snowline at 4,600 metres; on Mount Kilimanjaro, the lowest Pleistocene snowline stood above 1,300 metres. On Mount Ruwenzori, glaciers descended to about 2,900 metres on the western side and 2,000 metres on the eastern side, far below modern snowlines.
Glaciation also affected mountains that are not glaciated today. Mount Elgon in Uganda, the Semien Mountains, Mount Kaka, Mount Guna, Amba Farit, and Mount Chillalo are listed among the affected highlands. Solifluction, soil frost, glacio-fluvial deposits, and terraces connected with the Semliki River further support the conclusion that equatorial and sub-equatorial Africa was glaciated at least twice and became considerably cooler during the Würm.
Cᵉ siècle av. J.-C.
Equatorial East Africa, Ethiopian Highlands, Atlas Mountains
Traduction non disponible · Original (anglais) · français indisponible
Pleistocene African glaciation affected high mountain regions, especially in equatorial East Africa and the Ethiopian highlands, while the Atlas Mountains formed the principal exception outside East Africa. Former glaciers descended far below modern snowlines on Mount Kenya, Mount Kilimanjaro, Mount Elgon, Mount Ruwenzori, and several Ethiopian peaks. The excerpt concludes that equatorial and sub-equatorial Africa was glaciated at least twice and was especially cool during the Würm.
Poursuivre l’exploration
Le récit
Former African glaciation was concentrated in highlands, with nearly all known glaciated areas located in East Africa within a few degrees of the equator, apart from the Atlas Mountains. The elevations of these mountains range from roughly 3,900 to 6,100 metres. Snowfall nourishing the glaciers is attributed mainly to orographic precipitation carried by maritime air masses from the South Atlantic and, to a lesser extent, the Indian Ocean.
The evidence records dramatic differences between Pleistocene and modern snowlines. Mount Kenya’s Pleistocene snowline is estimated at 900 metres, compared with a present snowline at 4,600 metres; on Mount Kilimanjaro, the lowest Pleistocene snowline stood above 1,300 metres. On Mount Ruwenzori, glaciers descended to about 2,900 metres on the western side and 2,000 metres on the eastern side, far below modern snowlines.
Glaciation also affected mountains that are not glaciated today. Mount Elgon in Uganda, the Semien Mountains, Mount Kaka, Mount Guna, Amba Farit, and Mount Chillalo are listed among the affected highlands. Solifluction, soil frost, glacio-fluvial deposits, and terraces connected with the Semliki River further support the conclusion that equatorial and sub-equatorial Africa was glaciated at least twice and became considerably cooler during the Würm.
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