I am not an anthropologist, but I have studied history, and there is no case in the history of a mixed race which preserved a civilization, let alone which created one. Westerners have long wanted to get across the thesis that the pharaohs were half-breeds or whites, but to no avail. Black on White studies show that ancient Egypt was ruled by black pharaohs before being invaded by other races from the east.
Who can prove to me that a crossbreeding has already created a new civilization? You will continue to search, you will not find any as the hen continues to search for the needle of the hawk until today, tells a popular myth from here.
The Laws That Changed America: Kotz, Nick. (2005). 134 page.