LE3 .A278 2020

2020

Barr, Sandra

Acadia University

Bachelor of Science

Honours

Geology

Earth & Environmental Sciences

Mineral exploration has been done in the Faribault Brook area of the western Cape Breton Highlands, Nova Scotia, since the 1890s, but the age, structure, and tectonic setting of both the mineralization and its highly deformed metavolcanic and metasedimentary host rocks remain enigmatic. This study focuses on core from three exploration holes drilled in 1978, 1990, and 2008 and archived at the NS Department of Energy and Mines core library (Stellarton). Visual core logging combined with magnetic susceptibility measurements, petrographic study, and chemical analyses enabled identification of lithology in these mainly fine-grained, deformed and metamorphosed rocks. Hole AMC-06-79 (177.3 m) from near the Core Shack occurrence north of Faribault Brook consists of interlayered mafic metavolcanic, calc-silicate and garnet-rich metasedimentary rocks; the abundance of metavolcanic rocks increases with depth and metasandstone with blue detrital quartz clasts occurs at the top of the hole. Hole RB-90-01 (102.4 m) from near the Rocky Brook occurrence 7 km south of Faribault Brook also contains interlayered metasedimentary and metavolcanic rocks but metasedimentary units dominate in the upper and lower sections. Hole GM-09-08 (50 m) from the western part of the area consists of metasandstone with blue quartz clasts and interbedded siltstone. All 3 holes contain more mineralization than recognized in company assessment reports. Elevated Pb-Zn occur mainly as stratabound layers in metasedimentary rocks whereas Cu and As are hosted in quartz-carbonate veins. Anomalous Au was found in two holes in both quartz veins with arsenopyrite (up to 6 ppm Au) and in metawacke with elevated Pb and Zn (e.g. 1236 ppb Au, 2465 ppm Pb, and 6086 ppm Zn). Although mineralization in the Faribault Brook area was previously assumed to be VMS-style, most mineralization in the three drill holes is in metasedimentary rocks, suggesting sedimentary exhalative (SedEx)-type with related epithermal veins.

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https://scholar.acadiau.ca/islandora/object/theses:3425