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The Laurentian Upland (or Laurentian Highlands) is a
physiographic region Physiographic regions of the world are a means of defining Earth's landforms into distinct regions, based upon the classic three-tiered approach by Nevin M. Fenneman in 1916, that separates landforms into physiographic divisions, physiographic pr ...
which, when referred to as the "Laurentian Region" or the Grenville geological province, is recognized by
Natural Resources Canada Natural Resources Canada (NRCan; french: Ressources naturelles Canada; french: RNCan, label=none)Natural Resources Canada is the applied title under the Federal Identity Program; the legal title is Department of Natural Resources (). is the dep ...
as one of five provinces of the larger Canadian Shield physiographic division. The
United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the 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, ...
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
plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ha ...
and dissected southern rim of the Canadian Shield in the province of
Québec Quebec ( ; )According to the Government of Canada, Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is ...
. It is a western extension of the
Laurentian Mountains The Laurentian Mountains (French: ''Laurentides'') are a mountain range in southern Quebec, Canada, north of the St. Lawrence River and Ottawa River, rising to a highest point of at Mont Raoul Blanchard, northeast of Quebec City in the Laurentid ...
, and continues across the
Ottawa Valley The Ottawa Valley is the valley of the Ottawa River, along the boundary between Eastern Ontario and the Outaouais, Quebec, Canada. The valley is the transition between the Saint Lawrence Lowlands and the Canadian Shield. Because of the surroun ...
into Ontario as the
Opeongo Hills The Opeongo Hills (sometimes called the Opeongo Mountains or Madawaska Highlands, particularly for the easternmost hills) are a range of hills in Southern Ontario, near Algonquin Provincial Park. The hills stretch from Opeongo Lake in Algonquin P ...
. Viewed from the
valleys A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams ove ...
of the
Ottawa Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...
and
St. Lawrence River The St. Lawrence River (french: Fleuve Saint-Laurent, ) is a large river in the middle latitudes of North America. Its headwaters begin flowing from Lake Ontario in a (roughly) northeasterly direction, into the Gulf of St. Lawrence, connecting ...
s, 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 Mount Raoul Blanchard (french: Mont Raoul-Blanchard) is the highest peak in the Laurentian Mountains, Quebec, Canada at . It is located in the La Côte-de-Beaupré Regional County Municipality, Quebec, La Côte-de-Beaupré RCM, north east of Quebe ...
is the highest peak. 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 The Gatineau River (french: Rivière Gatineau, ) 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. The river is long and drain ...
in the west (mean elevation 400 m) some 550 km to the
Saguenay River __NOTOC__ 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; the city of Saguenay is located on the river. It drains into the Saint Lawrence River. ...
in the northeast. Here it attains its maximum elevation north of
Quebec City Quebec City ( or ; french: Ville de Québec), officially Québec (), is the capital city of the Provinces and territories of Canada, Canadian province of Quebec. As of July 2021, the city had a population of 549,459, and the Communauté métrop ...
in the Réserve faunique des Laurentides (over 1000 m). Individual summits rise above the plateau surface:
Mont Sir Wilfrid Mont may refer to: Places * Mont., an abbreviation for Montana, a U.S. state * Mont, Belgium (disambiguation), several places in Belgium * Mont, Hautes-Pyrénées, a commune in France * Mont, Pyrénées-Atlantiques, a commune in France * Mont, Saà ...
(783 m) and Mont Tremblant in the west, Mont Sainte-Anne (815 m) at Quebec,
Mont Raoul Blanchard Mount Raoul Blanchard (french: Mont Raoul-Blanchard) is the highest peak in the Laurentian Mountains, Quebec, Canada at . It is located in the La Côte-de-Beaupré Regional County Municipality, Quebec, La Côte-de-Beaupré RCM, north east of Quebe ...
(1166 m),
Mont Bleu Mont may refer to: Places * Mont., an abbreviation for Montana, a U.S. state * Mont, Belgium (disambiguation), several places in Belgium * Mont, Hautes-Pyrénées, a commune in France * Mont, Pyrénées-Atlantiques, a commune in France * Mont, Saà ...
(1052 m) and Mont des Conscrits (1006 m) in Réserve faunique des Laurentides.
Cap Tourmente The Cap Tourmente National Wildlife Area is a National Wildlife Area (NWA) located on the north shore of the Saint Lawrence River in the National Provincial Capital Region of Quebec, established on 28 April 1978. It is one of the critical habit ...
(579 m) and
Mont des Éboulements Mont may refer to: Places * Mont., an abbreviation for Montana, a U.S. state * Mont, Belgium (disambiguation), several places in Belgium * Mont, Hautes-Pyrénées, a commune in France * Mont, Pyrénées-Atlantiques, a commune in France * Mont, Saà ...
(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 ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
and parts of Northern
Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...
,
Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
,
Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...
, and
New York State New York, officially the State of New York, is a state in the Northeastern United States. It is often called New York State to distinguish it from its largest city, New York City. With a total area of , New York is the 27th-largest U.S. stat ...
, and is recognized by the
United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the 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, ...
to include the
Superior Upland The Laurentian Upland (or Laurentian Highlands) is a physiographic region which, when referred to as the "Laurentian Region" or the Grenville geological province, is recognized by Natural Resources Canada as one of five provinces of the larger ...
. As a southern extension of the Canadian Shield, the
Adirondack Mountains The Adirondack Mountains (; a-dÉ™-RÄN-dak) form a massif in northeastern New York with boundaries that correspond roughly to those of Adirondack Park. They cover about 5,000 square miles (13,000 km2). The mountains form a roughly circular ...
of New York State might also be considered an extension of the Laurentian Upland.


Geology

The Laurentian Upland is primarily made up of ancient Precambrian
igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...
,
metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...
, and
sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...
rock. With the exception of the river valleys and
lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...
basins, it is a rolling to mountainous
peneplain 390px, Sketch of a hypothetical peneplain formation after an orogeny. In geomorphology and geology, a peneplain is a low-relief plain formed by protracted erosion. This is the definition in the broadest of terms, albeit with frequency the usage ...
that ranges from 800 to 1400 feet above sea level.


Superior Upland

The
Superior Upland The Laurentian Upland (or Laurentian Highlands) is a physiographic region which, when referred to as the "Laurentian Region" or the Grenville geological province, is recognized by Natural Resources Canada as one of five provinces of the larger ...
is the
province A province is almost always an administrative division within a country or sovereign state, state. The term derives from the ancient Roman ''Roman province, provincia'', which was the major territorial and administrative unit of the Roman Empire ...
of the Laurentian Upland which projects into the United States west and south of
Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...
. This upland, part of the Canadian Shield along with the
Adirondacks The Adirondack Mountains (; a-dÉ™-RÄN-dak) form a massif in northeastern New York with boundaries that correspond roughly to those of Adirondack Park. They cover about 5,000 square miles (13,000 km2). The mountains form a roughly circular d ...
, is a greatly deformed structure and is composed primarily of
igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...
and
metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...
crystalline rocks commonly associated with a rugged landscape. At some prehistoric period, this had a strong relief, but today the upland as a whole is gently rolling with the inter-streams surfaces being plateau-like in their evenness. Here they have elevations of 1,400 to in their higher areas, such as the
Misquah Hills The Misquah Hills are a range of mountains in northeastern Minnesota, in the United States. They are located in or near the Boundary Waters Canoe Area Wilderness within Superior National Forest. Eagle Mountain, the highest point in Minnesota at ...
and
Huron Mountains The 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 s ...
. In this province, we find a part of those ancient mountains regions that were initiated by crustal deformation and then reduced by a long continued erosion to a
peneplain 390px, Sketch of a hypothetical peneplain formation after an orogeny. In geomorphology and geology, a peneplain is a low-relief plain formed by protracted erosion. This is the definition in the broadest of terms, albeit with frequency the usage ...
of modern relief. A peneplain with the occasional moderately high monadnocks left behind during the peneplanation of the rest of the surface. The erosion of the region must have been far advanced in prehistoric times, even practically completed, because the even peneplain surface is overlapped by fossiliferous marine strata from an early geological date,
Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, êž’) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
. This shows that the depression of the region beneath an ancient sea took place after a long existence as dry land.Ojakangas, Richard W.; Matsch, Charles L. (1982). Minnesota's Geology. University of Minnesota Press, 15. . The extent of the submergence and the area over which the Palaeozoic strata were deposited are unknown. Because of the renewed elevation without deformation, erosion in later periods has stripped off an undetermined amount of the covering strata. The valleys by which the uplands are here and there trenched to moderate depth appear to be, in part at least, the work of streams that have been superposed upon the peneplain through the now removed cover of stratified rocks.
Glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...
has strongly scoured away the deeply weathered soils that presumably existed here in preglacial time. It left behind firm and rugged ledges in the low hills and swells of the ground and spread an irregular drift cover over the lower parts, whereby the drainage is generally disordered being deposited in lakes and swamps and elsewhere rushing down rocky rapids.


See also

*
Laurentian Mountains The Laurentian Mountains (French: ''Laurentides'') are a mountain range in southern Quebec, Canada, north of the St. Lawrence River and Ottawa River, rising to a highest point of at Mont Raoul Blanchard, northeast of Quebec City in the Laurentid ...
*
Opeongo Hills The Opeongo Hills (sometimes called the Opeongo Mountains or Madawaska Highlands, particularly for the easternmost hills) are a range of hills in Southern Ontario, near Algonquin Provincial Park. The hills stretch from Opeongo Lake in Algonquin P ...
*
Adirondack Mountains The Adirondack Mountains (; a-dÉ™-RÄN-dak) form a massif in northeastern New York with boundaries that correspond roughly to those of Adirondack Park. They cover about 5,000 square miles (13,000 km2). The mountains form a roughly circular ...
*
Misquah Hills The Misquah Hills are a range of mountains in northeastern Minnesota, in the United States. They are located in or near the Boundary Waters Canoe Area Wilderness within Superior National Forest. Eagle Mountain, the highest point in Minnesota at ...
*
Huron Mountains The 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 s ...
*
Porcupine Mountains The Porcupine Mountains, or Porkies, are a group of small mountains spanning the northwestern Upper Peninsula of Michigan in Ontonagon and Gogebic counties, near the shore of Lake Superior. The Porcupine Mountains were named by the native ...


References

{{coord, 46, 26, N, 74, 59, W, region:CA_source:kolossus-ruwiki, display=title Physiographic provinces Physiographic regions of the United States Mountain ranges of Canada Mountain ranges of Quebec