The geology of Ontario is the study of rock formations in the most populated province in Canada- it is home to some of the oldest rock on Earth. The geology in Ontario consists of ancient Precambrian igneous and metamorphic rock which sits under younger, sedimentary rocks and soils.
Around 61% of Ontario is covered by the Canadian Shield. The shield, as a whole, can further be divided into three sections- these are known as provinces. The northwestern parts of the Shield, located north and west of Sudbury, are known as the Superior province. This is the largest of the three sections, covering 70% of the Canadian Shield portion in Ontario. The Southern province is a narrow region from Sault Ste. Marie to Kirkland Lake. The South central part is dominated by the Grenville Province but flanked by two basins of Phanerozoic materials.
Abundant mineral deposits are found here and as a result are mined extensively.