Study of the leucogranite alterations in the Campados kaolin deposit (NW Portugal) - The weathering responsible for the kaolinization
Master thesis presented by José Bernardo R. Brilha , 1992, 176 p.
Abstract
This work has as main aims the global characterization of the mechanism responsible for this deposit genesis, namely:
- study of the mineralogical and geochemistry evolution of the primary minerals in the transition fresh rock-saprolite;
- kaolinite and other secondary mineralogical phases characterization;
- characterization of the dominant alteration process (weathering/hydrothermal).
The weathering, responsible for the kaolinization, is peculiar because the following causes:
- no gibsite was found, nevertheless this mineral is always present in other saprolites of the same area and even in the rest of the country;
- the very small percentage of mixed-layer minerals present in the studied samples allows the conclude about the dominance and intensity of the kaolinization/weathering phenomena.