Human Migration and Pleistocene African Humid Periods

These are  some MSA lithics from a larger surface scatter the Saharan Zone in Mauritania. The material is characterized by a Levallois and Laminar approach About 50% of the tools are tanged while the other artifacts have  a more general MSA- aspect. They are all made made from a course quartzite.

It should be noted, that Stone tools are poor indicators of population changes. In the Levant, both Neanderthals and Homo Sapiens produced Levallois-Mousterian stone-tool assemblages, and in East and North Africa, early H. sapiens used similar lithic tool-kits as their predecessors.

It is obvious, that hominins could only survive in the Sahara during episodes that were considerably more humid than today.

As early as in  1857, Heinrich Barth, one of the first systematic European “explorers” of Africa noted petroglyphs in the Erg Murzuk and discussed them in the context of past climate change.

The best known “Green Sahara” episode occurred during the early and mid-Holocene, and in some regions even earlier with the onset of the Bølling/Allerød.

The term means that at this time parts of North Africa were much more humid than today. Perennial lakes were abundant, and lake levels were much higher during this so-called African Humid Period (AHP). Pollen-based reconstructions also demonstrated increased humidity.

The Sahara during these Holocene humid phase was covered by a dense palaeoriver network with many channels containing very large alluvial fans where rivers divide into multiple branches in an inland area. Where these fans are located on the boundary between two river catchments, their distributary channels can temporarily link adjacent river systems, thus allowing water-dependant life to transfer from one basin to the next. Forests were abundant in the vicinity of lakes and rivers, but much larger areas, showed a mosaic of  semi-arid adapted Saharan, Sahelian, and Sudanian plant groups.

The Holocene humid episode was not the only one, and a series of Pleistocene African Humid Periods are currently known. This hold true for MIS5e at 130-120 k.a. One event is dated around 170 k.a. and another at 330 k.a. While the Sahara today acts as a barrier,  during these humid events the Sahara received intermittent faunal  dispersals from Central and West Africa and more rarely from Eurasia along the southern Mediterranean coast. One can imagine, that these events created large faunal (and hominin) refugia in North Africa throughout these periods. But even during drier times there certainly were many econiches  where Homo could survive. One example is the MIS4 (TL and OSL dates) occupation at Uan Afuda and Uan Tabu (MSA / Aterian).

It seems that over the African continent MSA ensembles developed very early during the time span of 500-300 k.a, for example at the Kapthurin Formation in East Africa and the Kathu Pan 1 site in South Africa.The early sites are certainly not associated with Homo Sapiens.  Recently an archaic Homo Sapiens, associated with a rich MSA industry, at Jebel Irhoud in Morocco  was dated by several lines of evidence to 315 k.a.  during a humid phase at the site.

Such data lead to the possibility that Homo sp. may have entered Southwest Asia from either North or East Africa, or both, but also that there may have been several dispersal events, involving different populations.



Middle Paleolithic Points and the Principle of Elongation

About Katzman

During my whole life I was fascinated by stone age artefacts. Not only the aesthetic qualities of these findings, but also the stories around them and the considerations arising from their discovery, are a part of my blog. Comments and contributions are allways welcome! About me: J.L. Katzman (Pseudonym). Born in Vienna. Left Austria in 1974 and did not regret. Studied Medicine and Prehistory at a German University. Member of a Medical Department at a German University. Copyright 2010-2017 by JLK. All Rights Reserved. You are welcome to use material in these posts so long as you cite the work.
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