|Author:||Lucas and St-Onge, 1991|
|Geological province:||Churchill Province|
|Geological subdivision:||Ungava Orogen / Narsajuaq Arc (Narsajuaq Terrane)|
Table des matières
The Sugluk Group was defined by Lucas and St-Onge (1991) to describe a kilometric strip of metasedimentary rocks distributed within the Narsajuaq Arc.
Lucas and St-Onge (1991) incorporates in the Sugluk Group graphitic and sulphidic semi-pelitic metasediment strips locally interstratifed with pelite and quartzite units (locally arkosic) or, more rarely, carbonate units (St-Onge and Lucas, 1992). The quartzite contains a high proportion of magnetite and changes locally to iron formation (St-Onge, 1992). The predominance of semi-pelites and the rarity of units characteristic of a platform environment suggest a relatively deep deposition environment.
Metasediments are dispersed throughout the Narsajuaq Arc and form strips of limited thickness.
Several detrital zircons were dated using a U-Pb method in a quartzite sample taken north of Salluit Bay. The oldest zircon was dated at >2545 Ma, while the youngest gave an age of 1830 ±3 Ma (Parrish, 1989). Some units of the group were intruded and metamorphosed to the granulite facies by tonalitic plutons dated 1830 Ma, this date would approximate deposition of sediments from the Sugluk Group (St-Onge et al., 1992).
|Isotopic System||Mineral||Crystallization Age (Ma)||(+)||(-)||Reference(s)|
Sedimentary rocks of the Sugluk Group are interpreted as deep-water deposits emplaced on the edge of an island arc complex. Geochronology of the Narsajuaq Arc units suggests a rapid burial of sediments likely as a result of overthrusting of units of various intrusive arc suites around 1830 Ma (Parrish, 1989; St-Onge et al., 1992).
No fossil has been reported.