page_title: Geology of Ontario
hierarchical_section_title: Geology of Ontario
caption_attribution_description: North American cratons and basement rocks. As radiometric ages were determined for the shield-like rocks on the continents which were either exposed at the surface, underlay the flat rocks, or were within the interior of the mountain belts, patterns of age intervals were determined. These old rocks have been called the "basement". This has been interpreted to mean that the continents had somehow grown by development of rock assemblages with these characteristic age parameters. The expanding continental nuclei are part of the "craton" which consist of both exposed and buried basement rocks.
context_page_description: The geology of Ontario consists of the study of the rock formations in the most populated province of Canada. Ontario has some of the oldest rocks on Earth. It is made up of ancient Precambrian igneous and metamorphic rock and overlain by younger sedimentary rocks and soils.
  About 61% of the province is covered by the Canadian Shield. The shield can further be divided into three sections or provinces. The northwestern parts of the Shield, located roughly north and west of Sudbury, are known as the Superior province is the largest of the three sections, covering about 70% of the 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.
  World-class mineral deposits can be found here and are mined extensively.
context_section_description: The geology of Ontario consists of the study of the rock formations in the most populated province of Canada. Ontario has some of the oldest rocks on Earth. It is made up of ancient Precambrian igneous and metamorphic rock and overlain by younger sedimentary rocks and soils.
  About 61% of the province is covered by the Canadian Shield.  The shield can further be divided into three sections or provinces. The northwestern parts of the Shield, located roughly north and west of Sudbury, are known as the Superior province is the largest of the three sections, covering about 70% of the 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.
  World-class mineral deposits can be found here and are mined extensively.
caption: Location of the Grenville and Superior Craton
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