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TitleGeology of the eastern Cobequid Highlands, Nova Scotia
AuthorMurphy, J B; Pe-Piper, G; Piper, D J W; Nance, R D; Doig, R
SourceGeological Survey of Canada, Bulletin 556, 2001, 61 pages,
PublisherNatural Resources Canada
Mediapaper; on-line; digital
File formatpdf
ProvinceNova Scotia
NTS11E/10; 11E/11; 11E/12; 21H/09
AreaCobequid Highlands
Lat/Long WENS-64.5000 -62.5000 45.7500 45.5000
Subjectsgeochemistry; regional geology; structural geology; bedrock geology; structural features; basement geology; folds; faults; metasedimentary rocks; volcanic rocks; plutonic rocks; igneous rocks; Avalon Terrane; Rockland Brook Fault; Mount Thom Complex; Bass River Complex; Gamble Brook Formation; Economy River Gneiss; Folly River Formation; Great Village River Gneiss; Jeffers Group; Warwick Mountain Formation; Dalhousie Mountain Formation; Frog Lake Pluton; Debert River Pluton; McCallum Settlement Pluton; Folly Lake Pluton; Economy river Pluton; Hart Lake Pluton; Byers Lake Pluton; Salmon River Pluton; Pleasant Hills Pluton; Gilbert Mountain Pluton; Paleozoic; Precambrian; Proterozoic; Devonian; Silurian; Ordovician; Carboniferous
Illustrationssketch maps; tables; graphs; plots; block diagrams; stereonets; ternary diagrams
ProgramCanada-Nova Scotia Mineral Development Agreement, 1984-1989
ProgramCanada-Nova Scotia Cooperation Agreement on Mineral Development, 1990-1992
Released2001 10 01; 2014 08 28; 2016 01 12
AbstractThe eastern Cobequid Highlands, part of the Avalon terrane in mainland Nova Scotia, include Late Proterozoic to Late Paleozoic rocks. The Rockland Brook Fault divides the highlands into two blocks. To the south, Late Proterozoic rocks include granitoid gneiss and amphibolite of the Mount Thom Complex, and the Bass River Complex which includes the 734 ± 2 Ma Economy River Gneiss, platformal metasedimentary rocks of uncertain age, and the ca. 610-580 Ma Great Village River Gneiss. Coeval supracrustal rocks consist of continental tholeiitic basaltic flows and dykes and interbedded turbidite sequences. North of the Rockland Brook Fault, similarly aged arc-related volcanic and sedimentary rocks occur. Taken together, Late Neoproterozoic rocks in the eastern Cobequid Highlands may expose an oblique section across a Neoproterozoic magmatic arc. Penetrative fabrics are interpreted to reflect ductile shear-zone deformation associated with sinistral intra-arc transtension and basin development, followed by dextral transpression resulting in deformation of the basin.

Late Ordovician to Early Devonian rocks comprise shallow marine sedimentary and volcanic rocks and probably correlate with the Arisaig Group to the northeast. Devonian-Carboniferous rocks comprise continental sedimentary rocks and intra-continental bimodal volcanic rocks (Fountain Lake Group) and coeval bimodal plutonic rocks (emplacement age ca. 360 Ma). Locally intense dextral transpression between the Visean and Namurian resulted in a positive flower structure, local isoclinal folds, and may be related to dextral movement on the Avalon-Meguma terrane boundary.