Brazil ranks
among the countries that have the largest reserves of bauxite in the world, the
most important being the Trombetas, Paragominas and Almerim areas.
Geomorphologically,
the region with bauxitic profiles is a large plateau (high plain), whose erosion
surface tends to lie between 160m and 200m high.
In the Amazon region,
the occurrences of bauxite tend to be at the higher part of the plateau, sometimes
on the surface and other times below a layer of clay that lie between 5m and 15m
thick.
A typical bauxitic profile consists of the following layers:
4 – organic soil with
an average thickness of 0.5m
3
– yellow clay that caps most bauxitic profiles, made up
of kaolinite (80%) and quartz, with a maximum thickness at the center of the plateau,
getting thinner towards the edges;
2–
a bauxitic layer with an average thickness of 10m, subdivided into three smaller
sub layers:
2c
– nodular bauxite;
2b
– ferruginous laterite;
2a
– dense to granular bauxite.
1
–
variegated clay.
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