That is fairly close to 2,500 generations. Just how much genetic drift in these small populations would that involve? Would they even recognize each other as 'human'?
Probably not long enough for speciation, maybe; but not something to 'breed' peace & harmony?
For true speciation I think you would need both total isolation and extreme selection pressure on the two groups, but I doubt if 70k years would be enough. A lot of the superficial traits certainly would change in that time (stature, skin color, hair form, etc.) if selection pressure was strong enough in particular directions.
Maybe some genetic types could offer an opinion on this question, if there are any still around.
Thanks. What I had in mind was along the lines of the ‘shaved monkey’ effect. Fighting rather than interbreeding.