Physical volcanology, lithogeochemistry, petrology, and tectonic setting of the Neoarchean volcanic rocks in the Sunset Lake area, Beaulieu River volcanic belt, Sunset Lake, Northwest Territories, Canada
Date
2022-08-19
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0001-5972-7157
Type
Thesis
Degree Level
Masters
Abstract
Neoarchean volcanic rocks of the Beaulieu River volcanic belt (ca. 2.6 Ga) are found in the
Sunset Lake area, located approximately 110 km east-northeast of Yellowknife, NT. Volcanic
rocks within the Beaulieu River volcanic belt are dominantly composed of tholeiitic basalts, calc alkaline basaltic andesites, and minor amounts of calc-alkaline rhyolites. The Beaulieu River
volcanic belt structurally overlies the ca. 2.9 Ga Sleepy Dragon complex and are conformably
overlain by turbidites of the Burwash Formation. The aim of this study is to identify the relative
age and stratigraphic relationship between the stratigraphy of the rhyolite dome in south Sunset
Lake area and the felsic rocks that host the Sunrise volcanogenic massive sulfide (VMS) deposit 6
km to the north.
The volcanic rocks of the southern portion of Sunset Lake area are more complex than
originally mapped at a 1:50,000 scale by Lambert (1988). They are volumetrically dominated by
lavas; however, the stratigraphy contains a significant (~ 15‒20 vol.%) amount of volcaniclastic
rocks, which are interpreted to have been deposited by debris flows and eruption fed density
currents in a submarine environment. This study shows that the volcanic succession consists of
massive and pillow andesite to basalt, mafic tuff to tuff breccia, and lesser amounts of massive
to in-situ brecciated, weakly quartz-feldspar phyric rhyolite, heterolithic felsic tuff to lapilli-tuff,
and felsic tuff to tuff breccia. The lavas range from tholeiitic to calc-alkaline affinities and share
similar trace element signatures to that of a typical modern arc. While the rhyolite dome in south
Sunset Lake area does not show significant mineralization, there are similarities in lithologies,
lithofacies, lithogeochemistry, and stratigraphy to that of the stratigraphy that hosts the Sunrise
deposit. The study will provide a better understanding of the stratigraphy, volcanic and tectonic
settings of the volcanic rocks in the Sunset Lake area, thereby also allowing for a better
understanding of the process that formed Archean volcanic belts within the Slave craton that
may contain VMS style mineralization.
Description
Keywords
Beaulieu River volcanic belt, volcanic rocks, Sunset Lake, Archean, Slave craton, felsic volcanic rocks, rhyolite dome, Sunrise deposit, Yellowknife Supergroup, volcanogenic massive sulfide
Citation
Degree
Master of Science (M.Sc.)
Department
Geological Sciences
Program
Geology