Laurentian Upland

The Laurentian Upland (or Laurentian Highlands) 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. [cite web |last=|first=| authorlink = | coauthors = |title=The Atlas of Canada |publisher=Natural Resources Canada |date=|url=http://atlas.nrcan.gc.ca/sites/english/maps/reference/anniversary_maps/physiographicregions/map.pdf |accessdate=2007-12-27 |format=PDF] The United States Geological Survey recognizes the Laurentian Upland as the larger general upland area of the Canadian Shield. [ [http://water.usgs.gov/GIS/metadata/usgswrd/XML/physio.xml Physiographic divisions of the conterminous U. S ] ] [ [http://tapestry.usgs.gov/physiogr/physio.html Physiographic Regions ] ] [cite web |last=|first=| authorlink = | coauthors = |title=Mesaba Energy Project, Joint Permit Application |publisher=Minnesota Public Utilities Commission |url=http://energyfacilities.puc.state.mn.us/documents/16573/Joint-Permit-Application(Section-7).pdf |accessdate=2007-12-27 |format=PDF]

Geography

The Laurentian Region, as recognized by Natural Resources Canada, is part of the plateau 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 Tremblant is the highest peak at roughly 875 meters.

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 Québec, 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. [ [http://geomaps.wr.usgs.gov/parks/province/laurent.html USGS Geology in the Parks ] ] 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. [Erwin Raisz, Physiographical Map of North America, in Espenshade, Edward B., Jr., and Joel L. Morrison, editors. Goode's World Atlas, 17th ed. Chicago: Rand McNally & Co. 1986.]

Geology

The Laurentian Upland is primarily made up of ancient Precambrian igneous, metamorphic, and sedimentary rock. [cite book |last=Ojakangas |first=Richard W. | authorlink = | coauthors = Matsch, Charles L. |title=Minnesota's Geology |publisher=University of Minnesota Press |year=1982 |pages=15 |isbn=0816609535 ] 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. [cite book |last=Lajoie |first=Paul G. | authorlink = | coauthors = |title=Soil Survey of Gatineau and Pontiac Counties, Quebec |publisher=Canada Department of Agriculture |year=1962 |pages=14 |isbn=]

See also

* Laurentian Mountains
* Opeongo Hills
* Adirondack Mountains
* Misquah Hills
* Huron Mountains
* Porcupine Mountains

References