The term Kovik Antiform was introduced by Lamothe (2007), as suggested by Hocq (unpublished), in order to describe Archean rocks forming the internal northern basement within the Ungava Orogen (units AKOV1 to AKOV10; Lamothe, 2007). However, this nomenclature adopted for a formal lithodemic unit does not comply with the North American Stratigraphic Code (1983, 2005). The units were thus transferred to the Kovik Complex, Archean to Paleoproterozoic (Charette and Beaudette, 2018). The Kovik Antiform is the lithotectonic domain which contains rocks of the Kovik Complex. The unit was formally renamed the Kovik Lithotectonic Domain by Vanier and Lafrance (2020). The Kovik Complex consists of ten units (Appkvk1 to Appkvk10; Lamothe, 2007), aligned with the new nomenclature. As the Ministère’s mapping work is carried out, units of the Kovik Domain will be better defined and reassigned to separate suites according to their composition and genetic class, thus completely replacing the Kovic Complex.
The Kovik Lithotectonic Domain forms an E-W oriented strip ~50 km wide in the central part of the Ungava Orogen. It is bordered to the south by the Ungava Trough (Northern and Southern domains). The northern contact, with the Narsajuaq Lithotectonic Domain, is marked by the Sugluk Shear Zone. Its longitudinal extension is poorly defined since rocks of the domain extend under Hudson Bay to the west and under Hudson Strait to the east.
All units in this lithotectonic domain were previously assigned to the Kovik Complex. This complex is an Archean to Paleoproterozoic assemblage of orthogneiss, paragneiss and intrusive rocks. This assemblage mainly includes tonalite or biotite ± hornblende ± epidote ± titanite ± allanite granodiorite (ApPkvk4, ApPkvk5 and ApPkvk6 units) showing varying proportions of mafic and metasedimentary rock enclaves (Taylor, 1982; St-Onge and Lucas, 1990, 1992; St-Onge et al., 1992). In the western part of the domain, these lithologies are commonly migmatized and intruded by white to pinkish granitoids. Rare klippes of highly deformed silicoclastic metasedimentary rock (ApPkvk3) and extrusive or intrusive mafic rock (Akvk1) are present in or near tonalitic intrusions. Late, metric to kilometric intrusions, ranging in composition from tonalitic to syenogranitic (ApPkvk7 to ApPkvk10), intrude into tonalites and granodiorites (St-Onge and Lucas, 1992).
New units were introduced in the Cape Wolstenholme (Charette and Beaudette, 2018) and Sirmiq Lake (Vanier and Lafrance, 2020) areas to better distinguish lithologies that were previously entirely grouped in the Kovic Complex. These units are presented in the table below.
|ARCHEAN AND PALEOPROTEROZOIC|
|pPnat||Nunatak Suite||Massive to slightly foliated granite|
|ApPavi||Arviq Suite||Foliated granodiorite|
|ApPgan||Gastrin Suite||Monzodiorite, monzonite, quartz monzodiorite, quartz monzonite; amphibolitized gabbro and pyroxenite|
|ApPcry||Crony Suite||Variably migmatized paragneiss, metatexite and diatexite|
|ApPnuk||Nanuk Complex||Felsic to intermediate gneiss and migmatites|
The Kovik Domain is a lithotectonic division of the Churchill Province. It is interpreted as a window on the parautochnous Archaean basement, equivalent to rocks of the Superior Craton, resulting from their late uplift during the Ungava Orogenesis (Lucas and St-Onge, 1992). Historically, three Archean ages (2882-2737 Ma) were obtained by Parrish (1989) and Scott and St-Onge (1995) from tonalite samples collected in the Kovik Domain. A Paleoproterozoic emplacement age obtained by Davis and Sutcliffe (2018) in one of the main units of the Kovik Domain indicates that the latter does not consist solely of Archean units. Further dating is needed to properly define this lithotectonic package, the nature of which remains uncertain.
Similar to the conclusions of Baragar (2015), Charette and Beaudette (2018) note that the new field observations do not support the presence of a continuous fine imbrication of volcanic or metasedimentary rocks of the Povungnituk Group along the Kovik Domain, as suggested by St-Onge and Lucas (1992). Klippes of highly deformed, migmatized paragneiss were observed only in some areas where the Povungnituk Group had been mapped. According to the authors, there is no reason why they cannot be Archean paragneiss klippes.
Publications Available Through SIGÉOM Examine
CHARETTE, B., BEAUDETTE, M. 2018. Geology of the Cape Wolstenholme Area, Ungava Orogen, Churchill Province, Southeast Ivujivik, Quebec, Canada. MERN. BG 2018-03, 2 plans.
DAVIS, D W., SUTCLIFFE, C N. 2018. U-Pb Geochronology of Zircon and Monazite by LA-ICPMS in Samples from Northern Quebec. UNIVERSITY OF TORONTO. MB 2019-01, 113 pages.
LAMOTHE, D. 2007. LEXIQUE STRATIGRAPHIQUE DE L’OROGENE DE L’UNGAVA. MRNF. DV 2007-03, 66 pages and 1 plan.
VANIER, M.-A., LAFRANCE, I. 2020. Geology of the Sirmiq Lake Area, Ungava Orogen, Nunavik, Quebec, Canada. MERN. BG 2020-02, 1 plan.
LUCAS, S.B., ST-ONGE, M.R.1992. Terrane accretion in the internal zone of the Ungava orogen, northern Quebec. Part 2: Structural and metamorphic history. Revue canadienne des sciences de la Terre; 1992, volume 29, n°4, pages 765-782. https://doi.org/10.1139/e92-065
NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE (NACSN), 1983. North American Stratigraphic Code. American Association of Petroleum Geologists Bulletin; volume 67, pages 841-875. http://archives.datapages.com/data/bulletns/1982-83/data/pg/0067/0005/0800/0841.htm
NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE (NACSN), 2005. North American Stratigraphic Code. American Association of Petroleum Geologists Bulletin; volume 89, pages 1547-1591. http://dx.doi.org/10.1306/07050504129
ST-ONGE, M.R., LUCAS, S.B. 1990. Evolution of the Cape Smith belt: Early Proterozoic continental underthrusting, ophiolite obduction and thick-skinned folding. In The Early Proterozoic Trans-Hudson Orogen of North America (Lewry, J.F. and Stauffer, M.R., editors). Geological Association of Canada; special paper 37, pages 313-351.
ST-ONGE, M.R., LUCAS, S.B. 1992. New insight on the crustal structure and tectonic history of the Ungava Orogen, Kovik Bay and Cap Wolstenholme, Quebec. Geological Survey of Canada; Paper 92-1C, pages 31-41. https://doi.org/10.4095/132846
ST-ONGE, M.R., LUCAS, S.B., PARRISH, R.R. 1992. Terrane accretion in the internal zone of the Ungava orogen, nothern Quebec. Part 1: Tectonostratigraphic assemblages and their tectonic implications. Canadian Journal of Earth Sciences; volume 29, pages 746-764. http://doi.org/10.1139/e92-064
TAYLOR, F.C. 1982. Reconnaissance geology of a part of the Canadian Shield, northern Quebec and Northwest Territories. Geological Survey of Canada; Memoir 399, 32 pages. http://dx.doi.org/10.4095/109241
Ministère de l’Énergie et des Ressources naturelles (MERN). Kovik Lithotectonic Domain. Quebec Structural Lexicon. https://gq.mines.gouv.qc.ca/lexique-stratigraphique/province-de-churchill/antiforme-de-kovik_en [accessed on Day Month Year].
Benoit Charette, P. Geo., M.Sc. firstname.lastname@example.org; Mélanie Beaudette, GIT, B.Sc. email@example.com (redaction)
Mehdi A. Guemache, P. Geo., Ph.D. (coordination); Mélina Langevin, GIT, B.Sc. (critical review); Simon Auclair, P. Geo., M.Sc. (editing); Céline Dupuis, P. Geo., Ph.D. (English version); Ricardo Escobar Moran (HTML editing).
Isabelle Lafrance, P. Geo., M.Sc. firstname.lastname@example.org; Marc-Antoine Vanier, Jr. Eng., M.Sc. email@example.com (redaction)
Mehdi A. Guemache, P. Geo., Ph.D. (coordination); Benoit Charette, P. Geo., M. Sc. (critical review); Simon Auclair, P. Geo., M. Sc. (editing); Céline Dupuis, P. Geo., Ph.D. (English version); Ricardo Escobar Moran (HTML editing).