Precambrian of the North American Craton

Abstract

The North American continent is made up of three great structural entities (Fig. 4.1). These are the North American craton which has the form of a large triangular block with its apex towards the south; and the Phanerozoic fold-belts of the Appalachian and Cordilleran systems which flank the craton to the south-east and south-west respectively. The Appalachian fold-belt, largely of Palaeozoic age, was stabilised very early in the Mesozoic era and is partly covered, by a blanket of younger sediments forming the coastal plain and continental shelf of the Atlantic margin. The Cordilleran belt has been active since late Precambrian times and has yet to be stabilised. A zone of seismic activity at the Pacific margin of the continent is continued in the island arc systems of the Aleutians and central America which link North America with Asia and South America.