Brazilian Oriental Amazon is geologically and geographically situated
between longitudes 44º and 50º W. and latitudes 6º and
12º S., within the Amapá and Pará states, bordered
of the east by the Maranhão state, on the west by the Amazonas
state and on the south by the Mato Grosso state border. Despite the
fact that the French Guyana is not part of the Brazilian territory,
it is part of the Oriental Amazon because of its proximity and
geological similarity. The Oriental Amazon size is approximately
2,000,000 km2, which corresponds to the size of Occidental Europe.
THE GOLD PROVINCES OF THE ORIENTAL AMAZON
This work is classificatory, for this reason we were obligated to
define with relative precision criteria for this classification.
The distribution of several gold mineralized macro regions in the
Oriental Amazon is due to a major geological factor which is :
windows which expose Pre-Cambrian shield rocks. As one can see on the
map, there are 4 gold "windows" in the Oriental Amazon :
the northern part of the state of Pará , Amapá and
French Guyana , Gurupi, the southern part of the state of Pará
and the northern part of the state of Mato Grosso.
These four "windows" were divided into eight gold provinces
not only based on geological criteria but also based on
economical-social and historical criteria.
The gold provinces are not ubiquitously mineralized in all their
extension. They show clear differentiation and the gold occurrences
follow well defined geological patterns. It is possible to notice in
one province a number of well defined gold zones following a specific
trend that , in this work, are called belts. The geological control
of these belts are due to structures. They are characterized by
concentrations of gold occurrences , in contrast to the absence of
concentrated occurrences outside of the belts. Each province can
contain several belts.
The Gold belts are not extensively mineralized. The geologic
differentiation of the belts make possible the existence of gold
districts in some areas where in others there is no or little or no
gold . The gold districts represent 20 to 50% of the belts and they
cover from 6 to 15% of the provinces.
The districts are formed by gold occurrences and deposits controlled
by local geological phenomena. The significant primary and secondary
mineralization represent a significant share of each district (10 to
30%). The eight provinces are:
