Minimalist wrote:
Meanwhile, the idea of sea-borne contact from Africa to South America is something I find quite appealing.
Hi minimalist -
While Paul is doing a better job of arguing cultural influences than Ivan van Sertima, there are also Asian trans-oceanic contact materials to consider. Ethnically, the Olmec and Mayan populations were B and D mitochondrial DNA haplogroup, i.l. Asian origin.
While we know contact from Africa occurred in later times, the question is how influential it was. The biggest problem here is the lack of excavation from coastal Africa. Cultural similarities are simply too weak to make a definitive statement - in other words "looks like" does not mean "is" or "were".
From Africa, you might want to consider emigration from the Sahara River region of Africa to the Pedra Furada, Brazil area ca. 35,000 BCE, with clovis technology spreading by sea north, and first appearing in coastal SE North America, then going up the rivers. While those people were largely killed off by impacts (and we're talking of an entire DNA haplogroup here), you might want to take a look at Ocanachee and Yuchee ethnographic materials, i.l Savanah River Culture. They had the appearance of North African berbers, but with a maximum male adult height of 5 feet.
The Cherokee called them Nunehi.
Unfortunately, most of this came to light after I finished my book. It will make it to a second edition, if there is one.