Canada's coniferous forests cover vast mineral reserves.
Coniferous forests form the world largest ecosystem. The northern coniferous forest, or taiga, extends across North America and northern Eurasia. The climate in this region consists of strong cold winters and short summers of less than three months. Trees in the taiga -- usually larch, spruce, fir and pine -- grow close together. A temperate coniferous forest covers the Pacific Northwest of the United States, from northern California to British Columbia, Canada.
Precambrian Age
The northern coniferous forest covers the most ancient rock formations on Earth. These rocks are located over northern and eastern Canada, northern Scandinavia, Eastern Europe and northern Russia. The rocks are from the Precambrian Age and were once huge mountains and volcanoes. The erosion and deformation of Earth's crust over geological time transformed these regions to vast, flat expanses of bare rock or rock covered with a thin soil. Such regional formations are called shields or platforms, depending on their geographical location. The Canadian Shield, the Baltic Shield and the Siberian platform consist mostly of crystalline rocks such as granite.
Basalt
Streams of molten lava from deep fissures in Earth's crust punctured the Precambrian shield areas during various geological periods between 252 million years ago to 1.7 billion years ago. The lava did not emerge at Earth's surface but cooled within the crust. Erosion and deformation over time exposed the lava as swarms of long basalt veins stretching from one center over hundreds and thousands of miles. Geologists call these veins dikes. The world's largest basalt dike swarms occurred in the Mackenzie River region of Canada.
Cascade Volcanoes
The Pacific Northwest coniferous forest grows over a large region of active volcanoes, the Cascade Volcanoes. Rocks found in this region included breccias, a cemented volcanic debris and andesites. Obsidian, a rapidly cooled and vitrified version of basalt, occurs widely in Oregon.
Mineral Ores
The combination of Precambrian shields and the injection into them of molten lava has produced vast areas of mineralization throughout the Northern Hemisphere's taiga. Norilsk in western Siberia is famous for its nickel ore deposits that occur together with iron, copper and platinum. The greenstone belt in Canada's Manitoba and Saskatchewan produces copper, zinc and gold.
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