Français
 
De Pas Supersuite
Stratigraphic label: [ppro]bdp
Map symbol: pPbdp

First published: 20 October 2016
Last modified:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Translation of original French

Informal subdivision(s)
Numbering does not necessarily reflect the stratigraphic position.
 
None
 
Author: Martelain, 1986
Age: Paleoproterozoic
Stratotype: None
Type area: Rielle Lake (NTS sheet 24A03) and Tudor Lake (sheet 23P14) areas
Geological province: Churchill Province
Geological subdivision: George Lithotectonic Domain
Lithology: Granitoids
Category: Lithodemic
Rank: Supersuite
Status: Formal
Use: Active

Background

The De Pas Supersuite is a polyphase syntectonic intrusion extending >440 km in a NNW-SSE to N-S orientation in the central portion of the Southeastern Churchill Province (SECP) in Quebec, in the George Lithotectonic Domain. This mass was first informally called the « Ungava Batholith » following the mapping of Bourque (1986, 1991) and Owen (1989), and then the « De Pas Batholith » by Martelain (1986). Extensive mapping work in the George Lithotectonic Domain (Danis, 1988, 1991; Owen, 1989; Bourque, 1991; Taner, 1992; van der Leeden, 1994, 1995; Hammouche et al., 2011; Simard et al., 2013; Lafrance et al., 2014, 2015, 2016; Charette et al., 2016) identified two large intrusive suites within the supersuite based on the presence or absence of orthopyroxene: the De Pas Charnockitic Suite and De Pas Granitic Suite. The unit was renamed De Pas Supersuite as part of the Southeastern Churchill Province synthesis (SECP; Lafrance et al., 2018) to comply with the North American Stratigraphic Code (NACSN, 1983, 2005).

 

Description

The De Pas Supersuite consists of two separate suites: the De Pas Charnockitic Suite and De Pas Granitic Suite. Each of these suites includes a lithodeme, the Bonaventure Pluton and Merville Pluton, respectively. The charnockitic suite is located mainly in the southern third of the George Lithotectonic Domain, while granitic suite units cross it in its entirety.

 

Thickness and Distribution

The De Pas Supersuite is a polyphase syntectonic intrusion NNW-SSE to N-S oriented that extends over 440 km long and 25 to 55 km wide within the George Lithotectonic Domain (Charette et al., 2018). Rocks assigned to De Pas Supersuite are also present in the eastern part of the Baleine Lithotectonic Domain, which is just west of the George Domain. The De Pas Supersuite is associated with a strong positive regional aeromagnetic anomaly crossing the centre of the SECP. In its western part, however, some of the rocks assigned to De Pas Supersuite are non-magnetic and are located outside this regional anomaly.

With an area of 14 138 km2, the De Pas Supersuite is the largest unit in the SECP. The granitic suite (11 656 km2) largely dominates the charnockitic suite (2482 km2).

Dating

U-Pb dating indicates a crystallization age for the De Pas Supersuite between 1840 and 1810 Ma (Krogh, 1986; Dunphy and Skulski, 1996; James et al., 1996; James and Dunning, 2000) and more specifically between 1840 and 1823 Ma for the De Pas Granitic Suite (Dunphy and Skulski, 1996).

More recent work on the Ministère’s 1/250 000 mapping between 2011 and 2016 yielded ages between 1861 Ma and 1813 Ma. Readers can refer to the granitic and charnockitic suites of the De Pas Supersuite for more details on these dates. Recent dating confirms the conclusions of Dunphy and Skulski (1996) and James et al. (1996) that the two magmatic suites of the De Pas Supersuite have a contemporary emplacement. In addition, this evolution is partly synchronous with the development of major regional shear corridors, particularly the Rivière George Shear Zone, along which the De Pas intruded.

Stratigraphic Relationship(s)

The De Pas Supersuite is interpreted by several authors to be associated with a Proterozoic magmatic arc environment connected to a subduction zone developed during the New Quebec Orogenesis (Dunphy and Skulsky, 1996; Martelain et al., 1998; Simard et al., 2013). Wardle et al. (1990, 2002) note that the magmatic arc could also be associated with a syncollisional component in the hinterland of the New Quebec Orogen.

The Ministère’s mapping work highlighted the transitional nature of the north-south contact between the two suites that make up the De Pas Supersuite. Thus, the main units of each of these suites, that is, the porphyraceous units (pPdep2 and pPcde2), have similar textural and mineralogical characteristics. Orthopyroxene, well preserved in the southern sector, is increasingly altered and completely replaced by a mix of serpentine and amphibole moving northward to an amphibole-biotite assemblage. Several outcrops exhibit rocks with and without orthopyroxene that show no cross-cutting relationships between them. It is therefore possible that the southern portion of the De Pas Supersuite represents a deeper portion of the intrusion that allowed the crystallization of orthopyroxene and the formation of charnockite, whereas the northern portion would be a more superficial part. It is also possible that the transition from orthopyroxene rock to orthopyroxene-free rock from south to north is a change in crystallization conditions, as the CO2-rich magma moves to a richer H2O magma.

Paleontology

Does not apply.

References

Author(s) Title Year of Publication Hyperlink (EXAMINE or Other)
BOURQUE, Y. Géologie de la région du lac Mina, (Territoire-du-Nouveau-Québec). Ministère de l’Énergie et des Ressources, Québec; ET 88-08, 39 pages. 1991 ET 88-08
BOURQUE, Y. Géologie de la région du lac Mina, Nouveau-Québec. Ministère de l’Énergie et des Ressources, Québec; DP 85-30, carte annotée. 1986 DP 85-30
CHARETTE, B. – LAFRANCE, I. – VANIER, M.-A. George Lithotectonic Domain, Southeastern Churchill Province, Nunavik, Quebec, Canada: Geological Synthesis. Ministère de l’Énergie et des Ressources naturelles, Québec. BG 2018-11. 2018 BG 2018-11
CHARETTE, B. – LAFRANCE, I. – MATHIEU, G. Géologie de la région du lac Jeannin (SNRC 24B). Ministère de l’Énergie et des Ressources naturelles, Québec. 2016 Electronic geological report
DANIS, D. Géologie de la région du lac Recouet (Territoire-du-Nouveau-Québec). Ministère de l’Énergie et des Ressources, Québec; ET 86-11, 60 pages, 4 plans. 1988 ET 86-11
DANIS, D. Géologie de la région du lac Raude (Territoire-du-Nouveau-Québec). Ministère de l’Énergie et des Ressources, Québec; ET 88-10, 72 pages, 5 plans. 1991 ET 88-10
DUNPHY, J.M. – SKULSKI, T. Petrological zonation across the De Pas Batholith: a tilted section through a continental arc? In Eastern Canadian Shield Onshore–Offshore (ECSOOT) Transect Meeting 1996 (Wardle R.J. and Hall, J., editors). The University of British Columbia, Lithoprobe Secretariat; Report 57, pages 44-58. 1996
HAMMOUCHE, H. – LEGOUIX, C. – GOUTIER, J. – DION, C. – PETRELLA, L.
Géologie de la région du lac Bonaventure. Ministère des Ressources naturelles et de la Faune, Québec; RG 2011-03, 37 pages, 1 plan.
2011 RG 2011-03
JAMES, D.T. – DUNNING, G.R. U-Pb geochronological constraints for Paleoproterozoic evolution of the Core Zone, southeastern Churchill Province, northeastern Laurentia. Precambrian Research; volume 103, pages 31-54. 2000 Source
JAMES, D.T. – CONNELLY, J.N. – WASTENEYS, H.A. – KILFOIL, G.J. Paleoproterozoic lithotectonic divisions of the southeastern Churchill Province, western Labrador. Canadian Journal of Earth Sciences; volume 33, pages 216-230. 1996 Source
KROGH, T.E. Report to Newfoundland Department of Mines and Energy on isotopic dating results from the 1985-1986 geological research agreement. Newfoundland Department of Mines and Energy, Mineral Development Division; Open File Report LAB 707. 1986
LAFRANCE, I. – CHARETTE, B. – VANIER, M.-A. Southeastern Churchill Province, Nunavik, Quebec, Canada: Geological Synthesis. Ministère de l’Énergie et des Ressources naturelles, Québec. Preliminary BG. 2018 Bulletin géologiQUE
 
LAFRANCE, I. – BANDYAYERA, D. – CHARETTE, B. – BILODEAU, C. – DAVID. J. Géologie de la région du lac Brisson (SNRC 24A). Ministère de l’Énergie et des Ressources naturelles, Québec; RG 2015-05, 61 pages. 2016 RG 2015-05
LAFRANCE, I. – BANDYAYERA, D. – BILODEAU, C. Géologie de la région du lac Henrietta (SNRC 24H). Ministère des Ressources naturelles, Québec; RG 2015-01, 62 pages. 2015 RG 2015-01
LAFRANCE, I. – SIMARD, M. – BANDYAYERA, D. Géologie de la région du lac Saffray (SNRC 24G-24F). Ministère des Ressources naturelles, Québec; RG 2014-02, 49 pages. 2014 RG 2014-02
MARTELAIN, J. Batholithe de De Pas. In Rapport d’activité 86. Ministère de l’Énergie et des Ressources, Québec; DV 86-14, pages 48-49. 1986 DV 86-14
MARTELAIN, J. – CHENEVOY, M. – BÉLANGER, M.  Le batholite de De Pas, Nouveau-Québec / infrastructure composite d’arc magmatique protérozoïque. Revue canadienne des Sciences de la Terre; volume 35, pages 1-15. 1998 Source
OWEN, J.V. Géologie de la région du Lac Leif (Territoire-du-Nouveau-Québec). Ministère de l’Énergie et des Ressources du Québec; ET 87-18, 54 pages, 3 plans. 1989 ET 87-18
SIMARD, M. – LAFRANCE, I. – HAMMOUCHE, H. – LEGOUIX, C. Géologie de la région de Kuujjuaq et de la Baie d’Ungava (SNRC 24J et 24K). Ministère des Ressources naturelles, Québec; RG 2013-04, 60 pages. 2013 RG 2013-04
TANER, M.F. Reconnaissance géologique de la région du lac Juillet, Territoire-du-Nouveau-Québec. Ministère de l’Énergie et des Ressources, Québec; MB 91-19, 132 pages, 7 plans. 1992 MB 91-19
VAN DER LEEDEN, J. Géologie de la région du lac Mistinibi (Territoire du Nouveau-Québec). Ministère des Ressources naturelles, Québec; MB 95-45, 112 pages, 3 plans.
1995
MB 95-45
VAN DER LEEDEN, J. Géologie de la région du lac de la Hutte Sauvage (Territoire du Nouveau-Québec). Ministère de l’Énergie et des Ressources, Québec; MB 94-32, 108 pages, 2 plans. 1994 MB 94-32
WARDLE, R.J. – JAMES, D.T – SCOTT, D.J. – HALL, J. The southeastern Churchill Province: synthesis of a Paleoproterozoic transpressional orogen. Canadian Journal of Earth Science; volume 39, pages 639-663. 2002 Source
WARDLE, R.J. – RYAN, B. – NUNN, G.A.G. – MENGEL, F.C.
Labrador segment of the Trans-Hudson Orogen: crustal development through oblique convergence and collision. In The Early Proterozoic Trans-Hudson Orogen of North America (J.F. Lewry and M.R. Stauffer, editors). Geological Association of Canada; Special Paper 37, pages 353-369.
1990
NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE (NACSN) North American Stratigraphic Code. American Association of Petroleum Geologists Bulletin; volume 67, pages 841-875. 1983 Source
NORTH AMERICAN COMMISSION ON STRATIGRAPHIC NOMENCLATURE (NACSN) North American Stratigraphic Code. American Association of Petroleum Geologists Bulletin; volume 89, pages 1547-1591. 2005 Source
 
20 août 2020