Chemical weathering is the process by which rocks are broken down by chemical reactions. There are different types of chemical weathering. Hydrolysis is the chemical breakdown of a substance when combined with water. The most common example of hydrolysis is feldspar in granite rocks changing to clay.
Racially Africans originated in Africa, Europeans in Europe and so on. (before that the human species originated in Africa, but that's ancient history) African Americans are an ethnic group, or a subrace of the African race.
(Redirected from Jamaicans of African ancestry) Afro-Jamaicans are Jamaicans of entirely or predominantly African descent. The first Africans to arrive came in 1513 from the Iberian Peninsula. They were servants, cowboys, herders of cattle, pigs and horses, as well as hunters.