I recently fell down a rabbit hole -- as you do in 2020 -- and wound up with an extremely specific question:
So, the Tichett culture in southwest Mauritania, Africa appears to have emerged from the Sahara as a fully-formed sedentary group of farmers and herders around 2,000BC. They built a city over dozens of hectares, complete with social stratification. They thrived until 500 BC, when climate change forced them to abandon their cities to the Sahara.
My question then is, are we sure climate change isn't what happened the first time too? Geologists have definitively proven that the ancient Tamanrasset River Delta ran dry in Mauritania around the same time the Tichett appear. We know where the dry riverbeds are. Has anyone shown any interest in scouting the ancient riverbanks for signs of human habitation on a large scale? Other areas of the world had advanced proto-urban cultural sites in the same time period as the African Humid Period. Could it be possible that the Tichett "emerged" as a complex society because they weren't new, but simply fleeing from the Sahara that would continue to chase them?
Funny enough, there are a few folks who I’m aware have been doing this kind of archaeological work, specifically Dr. Peter Coutros during his PhD, in the middle Senegal Valley. Not exactly Tichett, but the site of Diallowali is in northern Senegal and temporally close.
I would also recommend you look into the work of Rod McIntosh and Susan Keech, and those who have looked into the social complexity at massive urban sites (which lack any evidence of strong social stratification, like a king) such as Jenne-jeno in the Middle Niger. Some distance away, but there have been a few folks curious enough to look into this part of the world to ask these questions.
Shoot me a private message if you’re having trouble finding sources or downloading them and we can figure something out.