Was it that big of a barrier if Taforalt was 1/3 SSA?
ratchet: I interpret what Angela is saying is that the Sahara Desert, which is could be 7 million or so years old, at least 2-3 million, when it is in its Dry phase is a barrier to migration.
https://www.worldatlas.com/articles...frican,ranging from 2 to 3 million years ago.
The Dry Sahara has been in place 3,000 BC, and the decrease in rainfall probably started 1K years earlier, and will likely not return to a Green Sahara, more rain and more desert like you see in Arizona maybe, till around 17,000 AD, the Green Sahara's last maybe a several thousand years before starting the cycle back to Dry Sahara, like now.
This brief Science article also suggest Sahara is 5-7 million years old and that is when the recurrent Sahara started, i.e. the pattern of Dry Sahara to Green Sahara.
From the article "Our results testify that the onset of recurrent desert conditions in the Sahara started at least 7 million years ago (5–7)."
https://science.sciencemag.org/cont...Nxrf5MajmKZnQMmLYVGc79qatAOR4Iq0siK4RQdEwYPAY
The Dry Sahara lasts usually for 20,000 years, which puts the next Green Sahara around 17,000 AD
https://www.livescience.com/23140-sahara-desert.html
The last Green Sahara period was for about 6,000 years.
https://phys.org/news/2017-01-green-sahara-ancient-rainfall-regime.html
So based on what the Scientist are telling us, there is Dry Sahara that last 20,000 years then a Green that might last 6,000 before starting the cycle back to Dry. So the Taroralt who was 1/3 SSA could have been in a Green period or traveled there during a Green period. Once the Dry Sahara kicked back in, trade between North Africa and SSA gets cut off as does migrations from SSA to North Africa. The Nile River however would allow for trade and commerce to happen between Egypt and the East African Horn, but as you move West, no.
In addition, I would think it was a Dry Sahara during OOA migrations as all the migration routes went East, either straight into West-Asia and perhaps some went up the Nile valley into NE Africa, then West Asia. Don't hold me to this hypothesis but it fits the way the Sahara has these recurrent long Dry periods to shorter Green periods.