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from both the Trans-Amazon and Tapajo´s-Parima orogenic belts to the east and northeast
(Santos al., 2003). The minimum age of the Roraima Basin was determined by U-Pb
geochronology from mafic sills to be 1782±3 Ma (Santos et al., 2003).
A number of U showings are spatially associated with the Roraima Basin. These
include the Aricheng albitite-hosted U mineralization (Fig. 5.7) and several other
occurrences hosted by the Kurupung Batholith in the basement near the Roraima Basin, in
western Guyana (Cinelu and Cuney 2006; Alexandre, 2010).
The Aricheng deposit is geologically similar to albitite-hosted deposits worldwide
(Cinelu and Cuney 2006, Alexandre, 2010). The Lagoa Real and Espinharas U deposits in
Brazil have host rocks that resemble those of around Kurupung Batholith in the Aricheng
deposit. Syn-ore hydrothermal zircon gives a minimum age of 1995±15 Ma for the U
mineralization (Alexandre, 2010), which is older than the age of the Roraima Basin. The
timing and style of U mineralization in the Aricheng deposit (Cinelu and Cuney 2006,
Alexandre, 2010) in Guyana and Lagoa Real (Lobato and Fyfe, 1990) and Espinharas
deposits (Porto de Silveira et al. 1991) in Brazil are similar to those of the granite-related U
mineralization in the Beaverlodge area (Dieng et al., 2011). This early U mineralization
associated with the underlying basement rock in the Roraima Basin could have been a
potential source for detrital uraninite in the younger Paleoproterozoic Roraima Basin as
most of the detritus in the basin were derived from Trans-Amazonian granitoids (Orestes
al., 2003) that host most of the U deposits in the successor basins.
The presence of early U mineralization in successor basins is thus a favorable
indication for unconformity-related U mineralization in the younger Paleoproterozoic
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