Explaining differences in settler-first peoples mating

Question

There was fairly little mixing between European settlers and the first peoples in what is today USA and Canada. There was extensive mixing in what is today Mexico (modern day: 65% Mestizo, 17.5% Amerindian, 16.5% White, 1% Black, Asian, or other, source: wiki: Mexico. Argentina had very little mixing (modern day: 97% European, 3% Mestizo, source: wiki: Argentina ).

Are there existing theories, literature?

Here are my rough ideas, (disclaimer: not backed up with research!)

Gender balance of settler community

If a settler community was considered a family destination (like the USA), then European men and women moved and had children with each other. Settler communities that were composed primarily of men would mate with women from the first peoples.

Religious conversion and development of new national identity

Shared religion and integration into a shared national community would make mating more likely. There was large-scale conversion to Catholicism among first peoples in Mexico. There was not large-scale conversion to the varieties of Christianity among first peoples in USA/Canada. Co-religionists would make more feasible mating partners. What is more, co-religionists could be more likely to develop a shared sense of national identity (e.g., as "Mexicans") than a people following very different religions. Having different senses of national identity would make people less likely to mate (e.g., in Canada and USA).

Answer 1

I personally don't like this question because it gives credence to racial theories. Scientifically speaking, there is more variation from individual to individual than there is between peoples of different ethnic backgrounds.

Anyway, addressing your question: One theory I've heard is that King Phillip's war was the cause. The idea behind this theory is simple: When the pilgrims arrived at Plymouth Rock in 1620, the Native Americans aided them in establishing themselves, and helped them not to starve, by teaching the pilgrims, people who had lived as refugees in the Urban Netherlands for a generation, to learn farming and survival skills. They even celebrated the first thanksgiving together. In New England, generally speaking, the contact between the Europeans and Natives Americans were more than cordial - there was intermarriage, and conversion to Christianity, and peaceful coexistence. The primary difference between the two populations was more one of lifestyle than one of race.

By about 1670, the mixing of the two populations, combined with declining Native American populations and quality of life, set the stage for "King Phillips War" Supporting Source and Wikipedia links. The common narrative goes like this: Metacom, a Native American nicknamed "King Phillip" by the settlers, started attacking and slaughtering the colonial population. The English colonialist responded in kind, slaughtering the Native American population. Both sides killed whichever "enemy" they came across, including women and children. Persons of mixed heritage were victims of both sides. 5% of the settler and 40% of the Native American population died. The general slaughter led to well defined racial identities that didn't exist before the war, and set the stage for future separate ethnic trends in North America.

There is, of course, an opposing theory presented in this book that the war was not about race at all, but was instead a civil war intended to increase British control of the region, which used "divide and conquer" strategies, split what was a unified community to increase colonial power. One results of the increase British control was marginalization of the Native population, and a stronger racial identity for the settlers.