Geology and Geosciences
Geology includes the study of the earth’s crust, its structure, the chemical composition and the physical properties of its components. Rock formations are located within the crust, their formation is studied and measurement is made of the forces that create, bend and shape mountains, basins, faults, volcanoes and earthquakes. Geology also examines the erosion of rocks and the deposition of the loose materials. It also reveals the physical history of the Earth.
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The seventeen geological provinces of Canada are characterized by rocks and structures of varying types and ages. They form one shield (consisting of seven geological provinces), four platforms, three orogens and three continental shelves.
Age of Rocks
The geologic time scale divides the 4.6 billion years of earth’s history into hierarchy of time periods. Every layer of rock corresponds to a specific time in the history of the formation of the Earth.
Canadian Geochronology Knowledgebase
The compilation represents publicly available geochronological information for Canada, with data compiled from federal, provincial and territorial government publications and reports, university theses, books and journal articles.
Major Rock Categories
Rocks are divided into three main categories according to how they were formed: igneous, sedimentary or metamorphic processes. Rocks differ in their texture, mineral and chemical composition, and bedding characteristics depending on which of these three processes that formed them.
Location of Kimberlites (1997)
Kimberlites are rock formation where diamonds can be found. Diamonds form at a depth greater than 150 kilometres within the earth. After their formation, diamonds are carried to the surface of the earth by strong volcanic activity. This mixture of magma, transported rock and diamonds forms pipes called kimberlites as it reaches the surface.
Contained within the 4th Edition (1974) of the Atlas of Canada is a map showing geological age and lithology accompanied by a supplementary map at a scale of 1:50 500 000, displaying geological provinces.
Surficial Materials and Glaciation
Most unconsolidated materials covering the Canadian landmass have glacial origins.
Some sediments were entrained by glaciers and deposited at a distance without being sorted. Other sediments were picked up and reworked by glacial melt water, or transported and deposited by river or wind action. Some sediments are organic or volcanic in origin. Sediments are classified according to the manner in which they were transported and deposited.
Contained within the 4th Edition (1974) of the Atlas of Canada is a map that shows the successive stages in the retreat of the last ice sheet in North America in respect to coverage of the Canadian landmass.
Contained within the 4th Edition (1974) of the Atlas of Canada is a set of two maps. One shows the maximum post-glacial marine limit in feet above present sea level and the second shows the maximum height of post-glacial rebound in feet above present sea level.
Canada’s landscape is diverse and comprises several distinct areas, called physiographic regions, each of which has its own topography and geology. The physical geography of Canada is divided into two vast sectors: the Shield and the Borderlands. The map shows the location of their physiographic regions.
Permafrost occurs when the ground remains at or below a temperature of 0°C for a minimum period of two years. Permafrost occurs not only at high latitudes but also at high altitudes. Almost all the soil moisture in permafrost occurs in the form of ground ice. Permafrost underlies about half of Canada’s landmass, as well as areas of the seabed in the western Arctic and is also believed to exist beneath the channels of the Arctic Islands.
Significant Earthquakes and Seismic Hazard
An earthquake is the rapid shaking of the Earth’s surface that follows the sudden release of energy within the Earth. Each year, more than 3500 mostly small earthquakes are recorded in or near Canada, 50 of which can be felt. The map shows the most significant earthquakes recorded in Canada to 2006.
There are many geologically active volcanoes along the Canadian Cordillera in British Columbia and the Yukon. The possibility of an eruption, even a large explosive one, cannot be ruled out. The map shows the major volcanoes and areas with significant accumulation of volcanic ash.
Space Weather - Geomagnetic Activity Zones
The magnetic field of the Earth is influenced by the electromagnetic environment of the solar system. Geomagnetic activity depends on the geographic location of the observing point. Geomagnetic activity can be described by the sizes of the disturbances in the Earth magnetic field and how often they occur. Canadian territory covers three zones of geomagnetic activity: the polar cap (north of Cambridge Bay), the auroral zone (between Cambridge Bay and Meanook) and the subauroral zone (south of Meanook).
Space Weather - Telluric Activity Zones
The magnetic field of the Earth is influenced by the electromagnetic environment of the solar system. The disturbed interplanetary environment changes the conditions of the natural electromagnetic environment of our planet and affects normal operation of space and ground technological infrastructures, such as power grids and pipelines. The geomagnetically induced currents that directly affect vulnerable infrastructure are driven by the geoelectric (telluric) field. This map shows the areas of Canada where ground infrastructure is most affected by space weather.
Major Landslides Causing Fatalities
Landslides are the downslope movements of sediment and rock. They can be found in any part of Canada, even in areas with very little relief. They happen in bedrock or in loose sediment, on land or under water. The map depicts 45 landslides in Canada that have resulted in more than 600 fatalities in historical times (1840 - 2006).
A tsunami is a sea wave or series of waves produced by large disturbances of the sea floor that are of relatively short duration. Since the beginning of the twentieth century, there has been one tsunami reported about every fifteen to twenty years in Canada. The map shows the location of the major tsunami events in Canada including earthquake and landslide events that triggered tsunamis.
Contained within the 4th Edition (1974) of the Atlas of Canada is a map that shows geologic structural features and denotes tectonic elements by a color-coding system. There are also descriptive elements and features of tectonic elements which are displayed.
Earthquakes, Magnetism and Tides
Contained within the 3rd Edition (1957) of the Atlas of Canada is a plate that shows maps of earthquakes, magnetism and tides across Canada.
The two larger upper maps on this plate show geomagnetism. The upper right map indicates the average annual change of magnetic variation in minutes. The small inset map at the top of this plate, entitled Earthquake Probability, shows the damage which may result from earthquakes occurring in different parts of the country.
The four lower maps on this plate show co-tidal and co-range lines for/from the semi-diurnal and diurnal tides. A co-tidal line indicates the position of the crest of the tidal undulation at a given time. A co-range line indicates the difference in level between the crest and the trough of the undulation.
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