A western riverine route for human migration to North Africa in the Abbassia Pluvial

Interesting study on paleo-rivers of the Sahara providing insight for a likely route for Homo sapiens to cross the Sahara towards NW Africa.

Tom J. Coulthard et al., Were Rivers Flowing across the Sahara During the Last Interglacial? Implications for Human Migration through Africa. PLoS ONE 2013. Open access → LINK [doi:10.1371/journal.pone.0074834]

Abstract


Human migration north through Africa is contentious. This paper uses a novel palaeohydrological and hydraulic modelling approach to test the hypothesis that under wetter climates c.100,000 years ago major river systems ran north across the Sahara to the Mediterranean, creating viable migration routes. We confirm that three of these now buried palaeo river systems could have been active at the key time of human migration across the Sahara. Unexpectedly, it is the most western of these three rivers, the Irharhar river, that represents the most likely route for human migration. The Irharhar river flows directly south to north, uniquely linking the mountain areas experiencing monsoon climates at these times to temperate Mediterranean environments where food and resources would have been abundant. The findings have major implications for our understanding of how humans migrated north through Africa, for the first time providing a quantitative perspective on the probabilities that these routes were viable for human habitation at these times.

Figure 2. Simulated probability of surface water during the last interglacial. This figure details Archaeological sites, and an annual probability that a location has surface water. The archaeological data are derived from a number of sources (including [42], [66], [67], [68]. The findspots are characterised by Aterian and Middle Stone Age artefacts such as bifacial foliates and stemmed Aterian points and/or typical ‘Mousterian’ points, side scrapers and Levallois technology. Most are represented by surface scatters but where stratified examples exist these can be shown by dating (OSL and U-series techniques) and geomorphological setting to belong within MIS 5e [41], [42].

As discussed in other occasions, it seems likely that some genetic remnants of those early migrations are still visible in at least some NW Africans.

See also:

• North African autosomal genetics through the prism of ADMIXTURE.
• Major upheaval of human Y-DNA phylogeny: we are all ‘A’ now (on some very ancient lineages shared by West and North Africans).

 

Sahara 5000 years ago: from grassland to desert in no time

Saharan dust storm blowing into the Ocean (NASA)

Live science reports about a new study, to be published in the Earth and Planetary Science Letters journal, that concludes, based on the dust sediments in the Atlantic Ocean, that the change from grassland to desert of the Sahara some 5000 years ago was very quick. 

In the wet period, known as Neolithic Semi-Pluvial, the dust accumulated in oceanic sediments was only 20% of present day. But that changed very fast around 5000 BP. 

Not many details are provided however.

 

Periodization of Saharan rock art

Marnie has a most interesting blogpost today on the periodization of Saharan rock art, specifically at Tadrart Acacus site in SW Lybia. It is not a well known matter so I am recycling her entry and the materials at Amis de l’Art Rupestre Saharien[fr/en/de/it] to make a quick visual note here on the matter.

Periodization dates are based on description at UNESCO site but need not to be correct for all pieces or not all authors need to agree to them. Here I follow that lead after some thoughts just because of its simplicity, which may well be misleading. It should only be taken as a very basic introductory note, nothing else.

Naturalistic or bubaline phase (14-10,000 BP):

··> more info at AARS.

Reminds a bit of rock art from Qurta (Nubia, Egypt).

Round head phase (10-6,000 BP):

··> more info at AARS.

Bovidian or Pastoral phase (6000-3500 BP):

··> more info at AARS.

As Marnie mentions, this phase would be approximately after the date of earliest clear evidence for milking in Africa, which is of c. 7000 BP.

Caballine phase (3500-2000 BP):

··> more info at AARS.

This would be soon after the date of arrival of the Hyksos to Egypt, who brought the chariot from Asia.

Cameline phase (since 2000 BP):

··> more info at AARS.

Dromedaries were probably introduced in Egypt (and the rest of Africa) with the Persian invasion c. 500 BCE.

 

Dairying in Africa some 7000 years ago

At least.

Julie Dunne et al. First dairying in green Saharan Africa in the fifth millennium bc. Nature 2012. Pay per view (supplementary information is accessible).

Abstract

In the prehistoric green Sahara of Holocene North Africa—in contrast to the Neolithic of Europe and Eurasia—a reliance on cattle, sheep and goats emerged as a stable and widespread way of life, long before the first evidence for domesticated plants or settled village farming communities1, 2, 3. The remarkable rock art found widely across the region depicts cattle herding among early Saharan pastoral groups, and includes rare scenes of milking; however, these images can rarely be reliably dated4. Although the faunal evidence provides further confirmation of the importance of cattle and other domesticates5, the scarcity of cattle bones makes it impossible to ascertain herd structures via kill-off patterns, thereby precluding interpretations of whether dairying was practiced. Because pottery production begins early in northern Africa6 the potential exists to investigate diet and subsistence practices using molecular and isotopic analyses of absorbed food residues7. This approach has been successful in determining the chronology of dairying beginning in the ‘Fertile Crescent’ of the Near East and its spread across Europe8, 9, 10, 11. Here we report the first unequivocal chemical evidence, based on the δ13C and Δ13C values of the major alkanoic acids of milk fat, for the adoption of dairying practices by prehistoric Saharan African people in the fifth millennium bc. Interpretations are supported by a new database of modern ruminant animal fats collected from Africa. These findings confirm the importance of ‘lifetime products’, such as milk, in early Saharan pastoralism, and provide an evolutionary context for the emergence of lactase persistence in Africa.

While there are some related articles (different author) that propose yogurt instead of milk as being the actual consumed product, this seems mostly a molecular-clock-o-logic wild speculation. Otherwise, the invention of yogurt is generally attributed to the steppe peoples (or Indians maybe) and arrived to the West only in the Middle Ages. There is no classical source discussing it at all (cheese or butter however are mentioned, as is raw milk) and instead Medieval Arab sources consider it a typical Turkish product. 

No African tradition exists of yogurt, unlike the case of butter or diverse ways of drinking raw milk, be it alone or mixed with blood.

Most likely, as in Europe and elsewhere, the relevant alleles pre-dated Neolithic changes (after all there’s no advantage in lactose intolerance, so no reason why it would have been fixated other than random drift) although they may have been somewhat favored by the development of Neolithic dairying, specially in areas where other foodstuffs were not easily available.

The archaeological site of Tadrar Acacus is at the in the Central Sahara, Fezzan region of Lybia, bordering the lands assigned to Algeria and Niger. Its chronology is illustrated in the supplemental figure 2:

click to expand

Equivalent evidence of dairying in Europe is from similar dates (or somewhat earlier in the Balcans and West Asia).

 

Tassili-n-Ajjer rock art is at least 9000 years old

Tassili-n-Ajjer, the famous rock art site of the Central Sahara has been dated to 9-10 millennia ago or older, using OSL techniques.

Sources[fr]: Pileta, Hominides.com.

Academic ref. (PPV):  Norbert Mercier, Jean-Loïc Le Quellec et al., OSL dating of quaternar y deposits associated with the parietal art of the Tassili-n-Ajjer plateau (Central Sahara), Quaternary Geochronolog y (2012), doi:10.1016/ j.quageo.2011.11.010

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Note to readers: I am going to attempt to at least limit posts that deal with too many unrelated issues. So expect more of these shorter snippets. I hope is best for all.