Grandroy Stock

Stratigraphic label: [narc]ggr

Map symbol: nAggr

First published: 5 February 2019
Last modified:

DISCLAIMER: This English version is translated from the original French. In case of any discrepancy, the French version shall prevail.

Informal subdivision(s)

Numbering does not necessarily reflect the stratigraphic position.

None

Author(s):	Graham, 1952
Age:	Neoarchean
Stratotype:	None
Type area:	Area north of Hématite Bay, in QTS sheet 32G16-200-0202.
Geological province:	Superior Province
Geological subdivision:	Abitibi Subprovince
Lithology:	Granodiorite
Category:	Lithodemic
Rank:	Lithodeme
Status:	Formal
Use:	Active

Related unit(s)

None

Background

The first description of the Grandroy Stock was given by Graham (1952).

Description

The intrusion consists of coarse-grained grey granodiorite in fresh exposure. Fracturing the rock results in alteration to chlorite, epidote and hematite giving the rock a beige to pink patina.

Thickness and distribution

The Grandroy Stock outcrops primarily on the shores of Hématite Bay (Chibougamau Lake), but some outcrops attributed to this stock have also been identified south of Bear Bay. The northern limit of the Grandroy Stock is marked by the Grondines Shear Zone.

Dating

None.

Stratigraphic Relationship(s)

North of Hématite Bay, the Grandroy Stock cuts mafic volcanic rocks of the David Member, volcanoclastic rocks of the Allard Member (2726.7 ±0.7 Ma; Leclerc et al., 2011) and mafic volcanic rocks of the Bruneau Formation (2724.4 ±1.2 Ma; Davis et al., 2014). West of Mount Sorcier, following Bear Bay, the Grandroy Stock cuts rocks of the Lac Doré Intrusive Suite anorthositic zone (2728.3 +1.2/-1.1 to 2727.0 ±1.3 Ma; Mortensen, 1993).

Paleontology

Does not apply.

References

Publications available through SIGÉOM Examine

DAVIS, D.W., SIMARD, M., HAMMOUCHE, H., BANDYAYERA, D., GOUTIER, J., PILOTE, P., LECLERC, F., DION, C., 2014. Datations U-Pb effectuées dans les provinces du Supérieur et de Churchill en 2011-2012. MERN, GEOCHRONOLOGICAL LABORATORY; RP 2014-05RP 2014-05, 62 pages.

GRAHAM, R B., 1952. CHIBOUGAMAU, ITS MINING POSSIBILITIES. MRN; S 015S 015, 9 pages.

Other publications

LECLERC, F., BÉDARD, J.H., HARRIS, L.B., McNICOLL, V., GOULET, N., ROY, P., HOULE, P. 2011. Tholeiitic to calc-alkaline cyclic volcanism in the Roy Group, Chibougamau area, Abitibi Greenstone Belt – Revised stratigraphy and implications for VHMS exploration. Canadian Journal of Earth Sciences; volume 48, pages 661-694. https://doi.org/10.1139/E10-088

MORTENSEN, J.K. 1993. U-Pb geochronology of the eastern Abitibi subprovince. Part 1 : Chibougamau – Matagami – Joutel region. Canadian Journal of Earth Sciences; volume 30, pages 11-28. https://doi.org/10.1139/e93-002

Suggested Citation

Ministère de l’Énergie et des Ressources naturelles (MERN). Grandroy Stock. Quebec Stratigraphic Lexicon. https://gq.mines.gouv.qc.ca/lexique-stratigraphique/province-du-superieur/stock-de-grandroy_en [accessed on Day Month Year].

Contributors

First publication

François Leclerc, P. Geo., Ph.D. françois.leclerc@mern.gouv.qc.ca (redaction)

Mehdi A. Guemache, P. Geo., Ph.D. (coordination); Céline Dupuis, P. Geo., Ph.D. (critical review and English version); Simon Auclair, P. Geo., M.Sc. (editing); André Tremblay (HTML editing).