Even more interesting, there are evidence of "negroids" in Brazil at that time, while the "mongoloids" people (the current native americans, that have features shared with asians) timeline seemly match the straight theory, some Brazillian historians believe that what happened is that the first attempt of colonizing South America failed somehow, and when the current natives arrived, they early settlers were already long gone.
As for a controversial archeological dig, one with 40.000 years ago humans in it, see https://en.wikipedia.org/wiki/Pedra_Furada_sites