1.2.2 Plate Tectonics

Tectonics is the study of how a planet's crust is a affected by deformation.

Deformation often involves folding (associated with mountain building) and faulting (large fractures).

The Earth’s crust has many folds and faults. It is actually made up of pieces or plates (eight large and approximately two dozen smaller plates) which move about in relation to one another like icebergs in the ocean.

As they move, the plates touch or rub against one another, collide with one another or stretch and fracture.

Their boundaries are delimited by transform zones, collision zones or spreading zones.

		Tectonic map of the Earth.
	Source

The North American tectonic plate has undergone many episodes of convergence and divergence in various places in the course of its geological history.

In Québec, these episodes resulted in the formation of three major geological domains or "physiographic regions".