Québec is divided into six large geological provinces based on the age and formation of rocks: the St. Lawrence Platform formed between 430-500 million years ago, the Appalachians Province formed between 330-570 million years ago, the Hudson Bay Platform formed between 410-450 million years ago, the Grenville Province formed between 600-2700 million years ago, the Churchill Province formed between 1100-2900 million years ago, and the Superior Province formed between 2500-4300 million years ago.

1. Geological Provinces
Québec is subdivided into six large arrays
called geological provinces. This subdivision is
based on the age of its rocks and on processes
associated with plate tectonic theory.
GRANITIC ROCK TONALITE ROCKS
Tonalite
This simplifi ed geological map displays the distribution of the main types of rocks, and the main
geological provinces found on Québec’s territory. Geologically speaking, rocks are subdivided
into three broad categories: igneous (intrusive and volcanic), sedimentary and metamorphic.
The age of these rocks plays an important role in understanding geological events.
St. Lawrence Platform (430 to 500 Ma)
Appalachians Province (330 to 570 Ma)
GT 2013-06
Research and writing: Robert Thériault, Stéphane Beauséjour and Julie Gagné
Graphics: André Tremblay
Produced and published: Ministère des Ressources naturelles
IGNEOUS ROCKS (intrusive)
Rocks that are formed by the cooling of the magma underground.
The slow crystallization of the magma leads to the creation of a granular texture.
MAFIC ROCK
Anorthosite Gabbro & diorite Pyroxenite,
peridotite & dunite
Impact slag Granite &
granodiorite
Syenite, monzonite
& jotunite
Orthopyroxene
granitoid rock
IGNEOUS ROCKS (volcanic)
Rocks that are formed when the magma cools on the surface
following the release of lava from a volcano.
Rhyolite & dacite Basalt & andesite Komatiite
SEDIMENTARY ROCKS
Rocks that are formed by the build-up
of sediments deposited in layers,
then consolidated after they are buried
deep inside the Earth’s crust.
TERRIGENOUS ROCKS
Wacke, mudrock,
slate & shale Sandstone
CARBONATED ROCK
Limestone & dolomite Conglomerate Iron formation
METAMORPHIC ROCKS
Rocks that are formed by the recrystallization of igneous or sedimentary rocks following
a rise in pressure and temperature deep inside the Earth’s crust.
IGNEOUS ROCK SEDIMENTARY BACKGROUND
Granit gneiss Tonalitic gneiss Migmatite Paragneiss Marble
Hudson Bay Platform (410 to 450 Ma)
Grenville Province (600 to 2700 Ma)
Churchill Province (1100 to 2900 Ma)
Superior Province (2500 to 4300 Ma)
Ma - Million years
FAULT
A breakage in the Earth’s crust,
indicating the movement
of two blocks of rocks that
are separated by the fault.
© State of New South Wales through the Department
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© Australian Museum
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© Prof. Dr. Michael Bau/Jacobs University Bremen
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