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African pluvial periods are an obsolete system of climatic periods previously used by
paleontologists
Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...
working in East Africa
East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...
.
Background
The sedimentary deposits left by ancient lakes inEast Africa
East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...
had enabled Louis Leakey
Louis Seymour Bazett Leakey (7 August 1903 – 1 October 1972) was a Kenyan-British palaeoanthropologist and archaeologist whose work was important in demonstrating that humans evolved in Africa, particularly through discoveries made at Olduvai ...
and post-war
A post-war or postwar period is the interval immediately following the end of a war. The term usually refers to a varying period of time after World War II, which ended in 1945. A post-war period can become an interwar period or interbellum, ...
paleontologists to define major climatic periods considered wet, interspersed with drier periods. Of progressively decreasing durations, they each bore the name of the site where the first clues had been collected: Kageran ( Kagera), Kamasian, Kanjeran (Kanjera) and Gamblian. Paleontologists believed that the quasi-arid zones then became wooded savannahs
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the Canopy (forest), canopy does not close. The open canopy allows sufficient li ...
where animals and prehistoric hunter-gatherers
A hunter-gatherer or forager is a human living in a community, or according to an ancestrally derived lifestyle, in which most or all food is obtained by foraging, that is, by gathering food from local naturally occurring sources, especially w ...
could thrive.
Chronology
These ancient climatic periods were only very approximately dated: * Kageran: Calabrian (Early Pleistocene
The Early Pleistocene is an unofficial epoch (geology), sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently esti ...
)
The Kageran takes its name from the Kagera River
The Kagera River, also known as Akagera River, or Alexandra Nile, is an East African river, forming part of the upper headwaters of the Nile and carrying water from its most distant source.Stanley, H.M., 1899, Through the Dark Continent, London: ...
, which flows through Rwanda
Rwanda, officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of East Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equator, Rwanda is bordered by ...
and northwestern Tanzania
Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...
before flowing into Lake Victoria
Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropics, tropical lake, and the world's second-largest fresh water lake by surface are ...
.
* Kamasian: Early Middle or Central Pleistocene; the Kamasian was more or less related to the Mindel glaciation
The Mindel glaciation (, also ''Mindel-Glazial'', ''Mindel-Komplex'' or, colloquially, ''Mindel-Eiszeit'') is the third youngest glacial stage in the Alps. Its name was coined by Albrecht Penck and Eduard Brückner, who named it after the Swabi ...
Kamasian is a district of Kenya
Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. ...
located in the Great Rift Valley
The Great Rift Valley () is a series of contiguous geographic depressions, approximately 6,000 or in total length, the definition varying between sources, that runs from the southern Turkish Hatay Province in Asia, through the Red Sea, to Moz ...
.
* Kanjeran: Late Middle Pleistocene
The Chibanian, more widely known as the Middle Pleistocene (its previous informal name), is an Age (geology), age in the international geologic timescale or a Stage (stratigraphy), stage in chronostratigraphy, being a division of the Pleistocen ...
; the Kanjerian was more or less related to the Riss glaciation
The Riss glaciation, Riss Glaciation, Riss ice age, Riss Ice Age, Riss glacial or Riss Glacial (, ', ' or (obsolete) ') is the second youngest glaciation of the Pleistocene epoch in the traditional, quadripartite glacial classification of the Alps ...
Kanjera is a site in Kenya
Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. ...
located on the shores of Lake Victoria
Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropics, tropical lake, and the world's second-largest fresh water lake by surface are ...
.
* Gamblian: Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...
; the Gamblian was more or less related to the Würm glaciation
The Würm glaciation or Würm stage ( or ''Würm-Glazial'', colloquially often also ''Würmeiszeit'' or ''Würmzeit''; cf. ice age), usually referred to in the literature as the Würm (often spelled "Wurm"), was the last glacial period in the ...
The term Gamblian was introduced by Louis Leakey
Louis Seymour Bazett Leakey (7 August 1903 – 1 October 1972) was a Kenyan-British palaeoanthropologist and archaeologist whose work was important in demonstrating that humans evolved in Africa, particularly through discoveries made at Olduvai ...
in the 1930s.
New climatic division
These ancient climatic periods have been gradually replaced in the scientific literature by the isotopic chronology in force since the end of the 20th century, which defines the alternation ofglacial
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
and interglacial periods on a global scale. Interglacial periods are warmer and, therefore, wetter on average than ice ages. The latter, however, themselves experience alternations of more or less heavy rainfall, but at a much faster rate (on a geological scale) than what had originally been imagined for East Africa
East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...
.
See also
*Interglacial
An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...
* Sahara pump theory
* Abbassia Pluvial
The Abbassia Pluvial was an extended wet and rainy period in the climate history of North Africa, lasting from c. 120,000 to 90,000 years ago.
As such it spans the transitional period connecting the Lower and Middle Paleolithic.
As with the sub ...
* Mousterian Pluvial
The Mousterian Pluvial is a mostly obsolete term for a prehistoric wet and rainy (pluvial) period in North Africa. It was described as beginning around 50,000 years before the present ( BP), lasting roughly 20,000 years, and ending ca. 30,000 BP ...
References
Bibliography
* * Climate of Africa Paleoclimatology Pleistocene {{paleoclimatology-stub