Laurentian Upland
Encyclopedia
The Laurentian Upland is a physiographic province
which, when referred to as the "Laurentian Region," is recognized by Natural Resources Canada
as one of five provinces of the larger Canadian Shield
physiographic division. The United States Geological Survey
recognizes the Laurentian Upland as the larger general upland area of the Canadian Shield.
and dissected southern rim of the Canadian Shield in the province of Québec
. It is a western extension of the Laurentian Mountains
, and continues across the Ottawa Valley
into Ontario as the Opeongo Hills
. Viewed from the valleys
of the Ottawa
and St. Lawrence Rivers, the south-facing escarpments of the Shield give the appearance of mountains 500–800 meters high; looking across the plateau, the relief is more moderate and subdued. These scarps mark the dramatic southern edge of this Upland region, of which Mont Raoul Blanchard is the highest peak at roughly 1,166 meters(3,825 ft).
Although the other limits are less well defined, this Laurentian Region in Quebec may be considered to extend 100–200 km northward from the scarps
and to stretch from the Gatineau River
in the west (mean elevation 400 m) some 550 km to the Saguenay River
in the northeast. Here it attains its maximum elevation north of Quebec City in the Réserve faunique des Laurentides (over 1000 m). Individual summits rise above the plateau surface: Mont Sir Wilfrid (783 m) and Mont Tremblant in the west, Mont Sainte-Anne (815 m) at Quebec, Mont Raoul Blanchard (1166 m), Mont Bleu (1052 m) and Mont des Conscrits (1006 m) in Réserve faunique des Laurentides. Cap Tourmente
(579 m) and Mont des Éboulements (770 m) are dramatic examples of the scarp face as it drops precipitously to the St Lawrence River.
The more general Laurentian Upland Province may be considered to extend over a larger area of the Canadian Shield, into Northwestern Ontario
and parts of Northern Minnesota
, Wisconsin
, Michigan
, and New York State, and is recognized by the United States Geological Survey
to include the Superior Upland. As a southern extension of the Canadian Shield, the Adirondack Mountains
of New York State might also be considered and extension of the Laurentian Upland.
igneous, metamorphic
, and sedimentary rock. With the exception of the river valleys and lacustrine
basins, it is a rolling to mountainous peneplain
that ranges from 800 to 1400 feet above sea level.
Physiographic regions of the world
The physiographic regions of the world are a means of defining the Earth's landforms into distinct regions based upon classic 1916 three-tiered approach defining divisions, provinces, and sections...
which, when referred to as the "Laurentian Region," is recognized by Natural Resources Canada
Natural Resources Canada
The Department of Natural Resources , operating under the FIP applied title Natural Resources Canada , is the ministry of the government of Canada responsible for natural resources, energy, minerals and metals, forests, earth sciences, mapping and remote sensing...
as one of five provinces of the larger Canadian Shield
Canadian Shield
The Canadian Shield, also called the Laurentian Plateau, or Bouclier Canadien , is a vast geological shield covered by a thin layer of soil that forms the nucleus of the North American or Laurentia craton. It is an area mostly composed of igneous rock which relates to its long volcanic history...
physiographic division. The United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
recognizes the Laurentian Upland as the larger general upland area of the Canadian Shield.
Geography
The Laurentian Region, as recognized by Natural Resources Canada, is part of the plateauPlateau
In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...
and dissected southern rim of the Canadian Shield in the province of Québec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
. It is a western extension of the Laurentian Mountains
Laurentian mountains
The Laurentian Mountains are a mountain range in southern Quebec, Canada, north of the St. Lawrence River and Ottawa River, rising to a highest point of 1166 metres at Mont Raoul Blanchard, north east of Quebec City in the Reserve Faunique des Laurentides. The Gatineau, L'Assomption, Lièvre,...
, and continues across the Ottawa Valley
Ottawa Valley
The Ottawa Valley is the valley along the boundary between Eastern Ontario and Western Quebec along the Ottawa River. The valley is the transition between the Saint Lawrence Lowlands and the Canadian Shield...
into Ontario as the Opeongo Hills
Opeongo Hills
The Opeongo Hills are a range of hills in Southern Ontario, near Algonquin Provincial Park...
. Viewed from the valleys
River Valley
River Valley is the name of an urban planning area within the Central Area, Singapore's central business district.The River Valley Planning Area is defined by the region bounded by Orchard Boulevard, Devonshire Road and Eber Road to the north, Oxley Rise and Mohamed Sultan Road to the east, Martin...
of the Ottawa
Ottawa River
The Ottawa River is a river in the Canadian provinces of Ontario and Quebec. For most of its length, it now defines the border between these two provinces.-Geography:...
and St. Lawrence Rivers, the south-facing escarpments of the Shield give the appearance of mountains 500–800 meters high; looking across the plateau, the relief is more moderate and subdued. These scarps mark the dramatic southern edge of this Upland region, of which Mont Raoul Blanchard is the highest peak at roughly 1,166 meters(3,825 ft).
Although the other limits are less well defined, this Laurentian Region in Quebec may be considered to extend 100–200 km northward from the scarps
Escarpment
An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...
and to stretch from the Gatineau River
Gatineau River
The Gatineau River is a river in western Quebec, Canada, which rises in lakes north of the Baskatong Reservoir and flows south to join the Ottawa River at the city of Gatineau, Quebec...
in the west (mean elevation 400 m) some 550 km to the Saguenay River
Saguenay River
The Saguenay River is a major river of Quebec, Canada.It drains Lac Saint-Jean in the Laurentian Highlands, leaving at Alma and running east, and passes the city of Saguenay. It drains into the Saint Lawrence River at Tadoussac....
in the northeast. Here it attains its maximum elevation north of Quebec City in the Réserve faunique des Laurentides (over 1000 m). Individual summits rise above the plateau surface: Mont Sir Wilfrid (783 m) and Mont Tremblant in the west, Mont Sainte-Anne (815 m) at Quebec, Mont Raoul Blanchard (1166 m), Mont Bleu (1052 m) and Mont des Conscrits (1006 m) in Réserve faunique des Laurentides. Cap Tourmente
Cap Tourmente
The Cap Tourmente National Wildlife Area is a National Wildlife Area located on the north shore of the Saint Lawrence River in the Charlevoix region of Quebec established on 28 April 1978. It is critical habitat for the Greater Snow Goose during migration. Flocks of tens of thousands of these birds...
(579 m) and Mont des Éboulements (770 m) are dramatic examples of the scarp face as it drops precipitously to the St Lawrence River.
The more general Laurentian Upland Province may be considered to extend over a larger area of the Canadian Shield, into Northwestern Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
and parts of Northern Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, and New York State, and is recognized by the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
to include the Superior Upland. As a southern extension of the Canadian Shield, the Adirondack Mountains
Adirondack Mountains
The Adirondack Mountains are a mountain range located in the northeastern part of New York, that runs through Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer, Lewis, Saint Lawrence, Saratoga, Warren, and Washington counties....
of New York State might also be considered and extension of the Laurentian Upland.
Geology
The Laurentian Upland is primarily made up of ancient PrecambrianPrecambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
igneous, metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
, and sedimentary rock. With the exception of the river valleys and lacustrine
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
basins, it is a rolling to mountainous peneplain
Peneplain
A peneplain is a low-relief plain representing the final stage of fluvial erosion during times of extended tectonic stability. The existence of peneplains, and peneplanation as a geomorphological process, is not without controversy, due to a lack of contemporary examples and uncertainty in...
that ranges from 800 to 1400 feet above sea level.
See also
- Laurentian MountainsLaurentian mountainsThe Laurentian Mountains are a mountain range in southern Quebec, Canada, north of the St. Lawrence River and Ottawa River, rising to a highest point of 1166 metres at Mont Raoul Blanchard, north east of Quebec City in the Reserve Faunique des Laurentides. The Gatineau, L'Assomption, Lièvre,...
- Opeongo HillsOpeongo HillsThe Opeongo Hills are a range of hills in Southern Ontario, near Algonquin Provincial Park...
- Adirondack MountainsAdirondack MountainsThe Adirondack Mountains are a mountain range located in the northeastern part of New York, that runs through Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer, Lewis, Saint Lawrence, Saratoga, Warren, and Washington counties....
- Misquah HillsMisquah HillsThe Misquah Hills are a range of large hills or small mountains in northeastern Minnesota, in the United States. They are located in or near the Boundary Waters Canoe Area Wilderness within Superior National Forest...
- Huron MountainsHuron MountainsThe Huron Mountains are located in the Upper Peninsula of the U.S. state of Michigan, mostly in Marquette and Baraga counties, overlooking Lake Superior. Their highest peak is Mount Arvon which, at above sea level, is the highest point in the state of Michigan. Nearby Mt...
- Porcupine MountainsPorcupine MountainsThe Porcupine Mountains, or Porkies, are a group of small mountains spanning across the northwestern Upper Peninsula of Michigan in Ontonagon and Gogebic counties, near the shore of Lake Superior. The area is part of the Porcupine Mountains Wilderness State Park...