Geology of Canada

Canada's geological architecture is dominated by its central foundation, a Precambrian shield. This is the largest area of Archean rocks in the world, more than 2.5 billion years old. The oldest rocks found in Canada so far are dated at 4.0 billion years. Most of this Precambrian shield consists of granitic rocks and gneiss laced with sinuous greenstone volcanic belts and broader areas of sedimentary rocks. It was consolidated by the end of Paleoproterozoic time, and is also known as Laurentia. Its southeast portion, the Grenville Province, was stabilized about one billion years ago.

Orogenic belts between the Archean fragments contain younger deposits. There are continental, oceanic, and collisional deposits. Three younger deformed belts, mainly of Phanerozoic rocks (>545 Ma), surround the shield:

After the Appalachian and Innuitian belts were deformed, they were superimposed by extensive less deformed basins dominated by sedimentary rocks. Large parts of the Precambrian shield are covered by a thin layer of undeformed sedimentary rocks, mainly of early Paleozoic age. Cretaceous strata form basins, as in Hudson Bay, and fault-bounded troughs in and near Hudson Strait and north of Baffin Island. A westward-thickening wedge of Mesozoic and Cenozoic sediments was deposited in Western Canada Basin. This sediments were derived from elevated sources in the mountains of the deforming ancestral eastern Cordillera.

The long history of the Canadian shield is the reason for the existence of numerous mineral deposits, valuable ores and gemstones. Most famous incident is probably the great gold rush to Alaska, which was only one (and the biggest) of numerous rushes. Until today Canada produces a certain amount of various raw materials. Most important are Aluminum, Asbestos, Coal, Copper, Gold, Iron Ore, Lead, Nickel, Potash, Salt, and Zinc.

But all those interesting ores and rocks, are not very good for karst formation and the existence of caves. Only part of the rare sedments of Canada consist of limestone, or at least marble. And many of those areas lie in flat basins, with a high ground water table and no chance for the formation of caves. The most interesting cave areas of Canada are located at Vancouver Island at the west coast and in the southeastern part of Canada from the Great Lakes to the east coast.

Canada has an abundance of natural resources including crude oil, iron, nickel, zinc, copper, gold, lead, molybdenum, uranium, and diamonds. In the last years vast diamond deposits were discovered which made the country one of the largest diamond producer. Probably the most extraordinary resource are the nickel and copper ores of Sudbury, Ontario, which are the result of an ancient meteorite impact. The impact 18. bilion years ago caused a huge crater, 60km long, 30km wide, and 15km deep. It also created cracks through which mineral rich magma reached the surface and filled the crater.


See also


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