The objective of this project was the petrographic and geochemical characterization of the rocks
of the Uraricoera Complex, an orthoderived basement of the northwest portion of the state of
Roraima, leading to its subdivision into 5 main lithofacies: (1) biotite-hornblende metagranites
and gneisses; (2) biotite metagranites and gneisses; (3) biotite meta quartz syenites; (4)
granulites; and (5) metadiorites and amphibolites. In general terms, these rocks have chemistry
similar to type-I granitic associations, subalkaline, metaluminous to weakly peraluminous, with
calcium-alkaline affinity, probably related to a volcanic arc environment. From the existing
microstructures, it was possible to infer a high-grade metamorphism with a peak in granulite
facies, in addition to two retrometamorphisms, one in amphibolite to greenschist facies, and
another in greenschist to prehnite-pumpellyite facies.
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