You can't necessarily discern a person's racial makeup from just their skin tone so assuming these people have "microscopic amounts of black admixture" seems pretty ignorant. Basically you just made a list of light skin black people.
https://pdfs.semanticscholar.org/9f67/21bf5954d1129d0212bc4f...
http://journals.plos.org/plosbiology/article?id=10.1371/jour...