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TitleMetallogenic summary of the Meguma gold deposits, Nova Scotia
AuthorSangster, A L; Smith, P K
SourceMineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods; by Goodfellow, W D (ed.); Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5, 2007 p. 723-732
Year2007
Alt SeriesEarth Sciences Sector, Contribution Series 20070212
PublisherGeological Association of Canada, Mineral Deposits Division (St. John's, NL, Canada)
Documentserial
Lang.English
Mediapaper; DVD; digital
RelatedThis publication is contained in Goodfellow, W D; (2007). Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods, Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5
File formatpdf
ProvinceNova Scotia
NTS11D/11; 11D/12; 11D/13; 11D/14; 11D/15; 11D/16; 11E/01; 11E/02; 11E/03; 11E/07; 11E/08; 11F/04; 11F/05; 11F/06; 21A/02; 21A/07; 21A/08; 21A/09; 21A/10; 21A/16
AreaHalifax; Dartmouth
Lat/Long WENS -65.0000 -61.0000 45.5000 44.0000
Subjectseconomic geology; tectonics; mineral deposits; mineral occurrences; mineralization; gold; mineral potential; sedimentary rocks; carbonate rocks; carbonates; slates; greywackes; vein deposits; alteration; deformation; metamorphism; granites; tectonic setting; exploration; exploration methods; Meguma Gold Deposits; Meguma Group; Goldenville Formation; Halifax Formation; Ordovician; Paleozoic
ProgramConsolidating Canada's Geoscience Knowledge
ProgramTargeted Geoscience Initiative (TGI-3), 2005-2010
AbstractThe lower Ordovician Meguma Group of Nova Scotia consists of a lower thick unit of Goldenville Formation greywacke and an upper unit of black sulphidic Halifax Formation slate. The transition between the two units contains an Mn-rich horizon and Tremadocian fossils. The auriferous Goldenville formation comprises thick beds of light to dark grey sandy metagreywacke that contain thin beds of green chloritic silt and clay on the upper contact of each Bouma cycle. Occasionally at this stratigraphic horizon, the green slaty beds are replaced by a sequence of black sulphidic slate, which occurs abundantly throughout local stratigraphic sections.

Within these carbonaceous sections, auriferous ribbon (laminated, crack-seal) veins occur, commonly at the upper contacts of slate beds with the overlying metagreywacke. They may extend for several kilometres in length and 10s to 100s of bedding-parallel veins may occur in a single district. Also occurring are en echelon veins, various types of angular veins (smaller), pegmatitic veins, and cross cutting veins (larger). Veins that have undergone extensive deformation are sometimes juxtaposed with undeformed veins, indicating that the vein-forming process occurred over a substantial period of time during deformation. The veins and wall rocks both contain arsenopyrite with accessory pyrite, pyrrhotite, galena, and chalcopyrite; carbonate is ubiquitous. Isotopic studies suggest a biogenic origin for the sulphide and an origin for the carbonate as oxidized organic carbon. 40Ar/39Ar analyses of muscovite and other minerals related to the veins suggested an age circa 360 to 380 Ma and an origin related to Devonian granite emplacement has been suggested. More recently however, Re/Os dating of arsenopyrite suggests that the vein formation began with the onset of metamorphism circa 408 Ma. Other ages at about 375 Ma suggest a second vein-forming episode and perhaps continuous or episodic mineralization throughout deformation and intrusion of granites.
GEOSCAN ID224201