canadian shield

noun Geology.

1. the extensive region making up much of northern and central Canada underlain by Precambrian rocks that have been eroded to produce a low shieldlike profile.

noun

1. Also called: Laurentian Shield, Laurentian Plateau (in Canada) the wide area of Precambrian rock extending west from the Labrador coast to the basin of the Mackenzie and north from the Great Lakes to Hudson Bay and the Arctic: rich in mineralsSee shield (def. 7)