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 minerals
shield (sense 7)
Canadian Shield in American English
an area of about 2,000,000 sq mi (5,179,980 sq km) of Precambrian strata, consisting largely of granite, gneiss, marble, and other igneous and metamorphic rocks that occupy most of eastern and central Canada & part of NE U.S.