Afrocentristic theorists and ancient astronaut theorists don't agree on much, but one thing they share is a common belief that ancient texts can be used without any confirming evidence to generate radical revisions of ancient history. In Herodotus (2.102-111) we find an accounted of the mythical Egyptian pharaoh Sesostris, whom the Greek historian claims conquered lands as far north as modern Georgia. Archaeology fails to find any evidence of this, and most historians think the story is a corruption and exaggeration of events from the reigns of Ramesses II, Seti I, and possibly Senusret II. Later, Diodorus Siculus and Strabo magnified this pharaoh still further, making him the conqueror of the entire world. Needless to say, there is no evidence whatsoever of Egyptians in France, or England, or Spain.
Based on this, Robert Temple, the ancient astronaut theorist, argued in The Sirius Mystery (1976) that Colchis was an actual Egyptian colony and that it was through this colony that the sacred truth that flying space frogs from Sirius had given humanity civilization was passed from Egypt to Greece, and thus from the Greeks to the Dogon of Africa.
At least Temple stopped there.
Afrocentric theorist R. A. Jairazbhoy proposed in a 1988 article ("Egyptian Civilization in Colchis on the Black Sea") that not only was Colchis an Egyptian colony but because the Egyptians were racially identical with sub-Saharan West Africans (the ancestors of most African-Americans), Colchis was therefore a Black colony, and in fact all of the Greek myths associated with it were nothing more than Greeks misinterpreting Black Egypt's African pomp and splendor.
Strangely, there almost seemed to be confirming evidence of this. There is an actual population of African descendants living in Georgia. In 1988 Afrocentrist John G. Jackson explained why these people prove that Africa had conquered the classical world and gave it civilization:
This area has been called the ‘Black Soviet’ because there are so many Black people living down there. Of course they tell you in the history books that these people are the descendants of slaves that the Russians imported in the Middle Ages. But if this territory was settled by the Egyptians in ancient times, then these people are probably their descendants.
Quoted in James E. Brunson and Runoko Rashidi, “Sitting at the Feet of a Forerunner: An April 1987 Meeting and Interview with John G. Jackson,” in African Presence in Early Asia, eds. Runoko Rashidi and Ivan Van Sertima (New Brunswick: Transaction, 1988): 198.
For these 30 people to have been the remains of Sesostris' army requires us to assume that the Egyptians brought an army composed of both Black men and women, that they in-bred for three thousand years, never took any non-Black people for spouses, and somehow maintained a reproductively viable population in the face of isolation and discrimination. The Africans of Colchis knew the truth and tried to tell the Afrocentrists, who refused to listen. Ethnographers and archaeologists listened, and through their work we know the truth: They are the last descendants of Ottoman-era slaves from when the territory was part of Turkey.
This is a far cry from imaginary Egyptian armies and flying space frogs, but it has the virtue of being true.
2014 Note: I discuss this claim and other Afrocentric material related to the story of Jason and the Argonauts in my new book on the Argonauts, due out later this year.