EESA06H3 Chapter 20: Detailed Chapter 20 Notes
Document Summary
The construction of north america began about 4,000 million years ago with the formation of the acasta gneiss of the north west territories, which now forms part of the slave province of the canadian shield. The building of north america was essentially complete by 65 million years ago, although the modern landscape is the result of geologically recent glaciations that have occurred in the last 2. 5 million years. The last ice sheet left the southern portions of the country only 12,000 years ago, and finally melted in labrador 6,000 years ago. These rocks range in age from 4 - 1 billion years old and are largely devoid of fossils. The craton is composed of a complex assemblage of several distinct geologic provinces. Geologic provinces are broad regions of similar rocks, usually covering many thousands of square kilometers, with characteristics that differ significantly from rock types present in adjacent areas.
