Proposed Title 1: - Queen's University

Tectonic during and immediately after basin formation plays a critical role in the
formation of unconformity-related uranium mineralization. Deformation may prevent
alteration of the successor basin sediments by inhibiting fluids circulating into the basin
thereby reducing fluid-rock interaction. This is corroborated by the weakly to unaltered
character of the Martin Lake Basin sediments that were deposited at ca. 1820 Ma during
active tectonism associated with the Trans-Hudson Orogen (Hoffman, 1989). In contrast,
deformation was less intense in the South Alligator River area during the deposition of the
El Sherana Basin at ca. 1830 Ma immediately after the peak Nimbuwah Orogen (Needham
et al., 1988), thus promoting fluid-rock interaction and alteration of the El Sherana Basin
sediments. The spatial association of U deposits with successor basins may result from the
presence of pre-existing lines of tectonic weakness that focus both near and far field
deformation and can therefore be easily reactivated, creating structural traps that are
favorable for hydrothermal fluid flow and uranium mineralization.
5.2.1. Early U mineralization
Supracrustal rocks underlying successor basins are commonly affected by multiple
tectonic events and thereby metamorphosed, granitized and intruded by granitic rocks. In
the Beaverlodge area, early U mineralization predating the formation of the successor basin
is associated with thermotectonic activities accompanied by magmatism, regional
metamorphism, and hydrothermal alteration. On the basis of their structural setting, host
rock geology, timing and style of mineralization, the early U mineralization can be divided
into two main U mineralizing systems: the granite-related U mineralization and
metamorphic-related U mineralization systems (Fig. 5.1). Similarly, based on the origin and
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