Ok wrong wording what I meant by wiping was out expelling them and by exterminating there were a lot of examples such as the Mongols and Timurids, the Zulu in South Africa are just some that come to mind. But I guess your right it wasn't common but is wasnt unheard or new.
Modern science has already put many of these theories to rest. There was no Mongol-led extermination. Take a look at the DNA haplogroup charts of the Central Asian peoples, such as the Turkmens, Uzbeks, Uyghurs, etc. They're predominantly descended from the ancient Iranian populations. And the Mongol genetic influence was not only small but maternal-derived, which made these theories of extermination look even more dumbfounded. Bear in mind that the Mongols enjoyed spreading a false, negative image of themselves. It was part of their psychological warfare tactics to scare populations into surrendering without resistance, and it worked. You have the Persians to thank for spreading the propaganda to the Muslim world, since many Persian nobility worked for the Mongol government and were given high positions and gold in return for taking advantage of the high literacy rates in the Muslim world, by spreading the propaganda through various chronicles and letters.
I'm clueless about the Zulus however.
Anyway, this whole extermination thing is unrealistic. Why is it even necessary? The populations of native Americans were so small compared to the European settlers. Assimilation and absorption is better and doable. Anyway, it seems the native Americans were hellbent on fighting the settlers, which in itself warranted a military retaliation by the US, which would eventually lead to the loss of life. It would make more sense for the Americans to see how the natives react first, instead of going after them like barbarians.
Point is, the original poster's scenario is unrealistic.