Proposed Title 1: - Queen's University

and Slimmon, 1985) and B: NW-SE geological cross-sections across the Saint Louis fault (line
AA’) showing the geology, the trace of the Saint Louis Fault and the location of the uranium
mineralization (modified from Sassano, 1972).
The Donaldson Lake gneiss outcrops in the hanging wall and footwall of the fault
(Fig. 2.6B) and Sassano (1972) suggested that the Donaldson Lake gneiss is the cataclasite
equivalent of the underlying Foot Bay gneiss. The rock has a porphyroclastic texture
composed of Kfs 1 feldspars, Pl 1 plagioclase and Qtz 1 quartz scattered in a matrix of
recrystallized Qtz 1 quartz, crushed Kfs 1 feldspars and trails of Ms 1 muscovite and Chl 1
chlorite.
The quartzite occurs in the footwall (Fig. 2.6B) where it is mylonitized with strained
and recrystallized Qtz 1 quartz (Fig. 2.7B). Qtz 1 quartz grains are elongated and locally
wrapped by Src 1 sericite and Chl 1 chlorite. The mylonite is cut by Chl 2 chlorite and Src 1
sericite veinlets and overprinted by cataclasite with angular fragments of the mylonitized
quartzite occurring into the matrix (Fig. 2.7E).
The phyllonite amphibolite outcrops in the footwall, north of the Ace-Fay deposits.
In thin section, the rock shows symmetric crenulations that overprint the mylonitic fabric
(Fig. 2.7C). It is composed of alternating dark and light bands of Hbl 1 hornblende, Bt 1
biotite, Chl 1 chlorite, and Qtz 1 quartz, Kfs 1 feldspars and Src 1 sericite. In the amphibolite,
three fold phases (F1, F2 and F3) have been identified (Fig. 2.7D). F1 and F2 are isoclinal
recumbent folds having a dominant east-southeast axial plane foliation. Both F1 and F2 are
refolded by a north-northwest-trending open upright fold F3 producing a type 2
interference pattern (Ramsay, 1967). The amphibolite locally displays a breccia fabric with
mylonite fragments embedded in the matrix (Fig. 2.7H).
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