Lably
Skip to content

Great Lakes region

Region of the United States and Canada

  • 32 min read
  • 7 chapters
La Cloche Mountains 4x3
Ryan Hodnett · CC BY-SA 4.0

Related on Lably

Through Canada and Geology

State and provincial governments are represented in the Conference of Great Lakes and St. Lawrence Governors and Premiers, which also serves as the Secretariat to the Great Lakes St. Lawrence Compact and the Great Lakes–Saint Lawrence River Basin Sustainable Water Resources Agreement.

The Great Lakes region takes its name from the corresponding geological formation of the Great Lakes Basin, a narrow watershed encompassing the Great Lakes, bounded by watersheds to the region's north by the Hudson Bay, to the west by the Mississippi, and to the east and south by the Ohio. To the east, the rivers of St. Lawrence, Richelieu, Hudson, Mohawk and Susquehanna form an arc of watersheds east to the Atlantic.

The Great Lakes region, as distinct from the Great Lakes Basin, defines a unit of sub-national political entities defined by the U.S. states and the Canadian province of Ontario encompassing the Great Lakes watershed, and the states and province bordering one or more of the Great Lakes.

Since time immemorial Indigenous peoples have lived in the Great Lakes region. Historically, native tribes in the region have engaged in political alliances with other indigenous groups and maintained cultural kinship and harvesting relationships. For instance, Potawatomi peoples have organized culturally and politically through the ‘seasonal round’ system to adapt to environmental change. During the period of early European exploration and colonization in the region, policies aimed at western expansion encroached upon Native land, intending to remove Native Americans from their land and the U.S. political landscape. European settlement also affected Native American relationships with local ecosystems through removal from lands, industrialization, and environmental degradation, causing disconnection from cultural practices. Despite this, indigenous groups including the Anishinaabe and Potawatomi exercise self-determination through maintaining reciprocal relationships with the land and conservation projects including that of Lake Sturgeon.

The Great Lakes make up the world's largest freshwater system, supporting millions of people but have been historically impacted by pollutants from agricultural runoff, sewage disposal, and contamination from local industries leading to long-term environmental impacts and health implications for residents, as well as large-scale governmental policy responses. The region has seen several water quality crises including in 2014 in Toledo and Flint. These cases underscore the unequal impact of environmental harm on vulnerable minority communities in the region.

Geography

The Palaeozoic strata are parts of a great area of similar layers hundreds of feet in thickness. These strata decline gently southward from the great upland of the Laurentian Highlands of eastern Canada. The visible upland area of today was a small part of the primeval continent with the remainder of it still buried under a Palaeozoic cover. The visible part was the last part of the primeval continent to sink under the advancing Palaeozoic seas. This district may be considered an ancient coastal plain. The weaker layers are worn down in sub-parallel belts of lower land between the upland and the belts of more resistant strata, which rise in uplands. Illustrations of this type of forms are found in the district of the Great Lakes. The chief upland belt or escarpment is formed by the firm Niagara limestone/dolomite, which takes its name from the gorge and falls cut through the upland by the Niagara River. The Niagara Escarpment has a relatively strong slope or effacing escarpment on the side towards the upland, and a long gentle slope on the other side. Its relief is seldom more than 200 or 300 feet (91 m) and is generally small. Its continuity and its contrast with the associated lowlands on the underlying and overlying weak strata make it an important feature. The escarpment would lie straight east–west if the slant of the strata were uniformly to the south. However, the strata are somewhat warped and so the escarpment's course is strongly convex to the north in the middle, gently convex to the south at either end.

The escarpment begins where its determining limestone/dolomite begins, in west-central New York. There, it separates the lowlands that separate Lake Ontario from Lake Erie. It curves to the northwest through the Ontario province to the island belt that divides the Georgian Bay from Lake Huron. From there, it heads westward through the land-arm between Lake Superior and Lake Michigan and southwestward into the narrow points dividing Green Bay from Lake Michigan. Finally, it fades away with the thinning out of the limestone and is hardly traceable across the Mississippi River. The arrangement of the Great Lakes closely matches the course of the lowlands worn on the two belts of weaker strata on either side of the Niagara escarpment. Lake Ontario, Georgian Bay and Green Bay occupy depressions in the lowland on the inner side of the escarpment. Lake Erie, Lake Huron and Lake Michigan lie in depressions in the lowland on the outer side. When the two lowlands are traced eastward, they become confluent after the Niagara limestone has faded away in central New York, and the single lowland is continued under the name of the Mohawk Valley. This is an east–west longitudinal depression that has been eroded on a belt of relatively weak strata between the resistant crystalline rocks of the Adirondacks on the north and the northern escarpment of the Appalachian Plateau (Catskills-Helderbergs) on the south. Early in U.S. history, this provided a vital economic route between the Atlantic seaports and the U.S. interior.

In Wisconsin, the inner lowland is a knob of resistant quartzites, known as Baraboo Ridge, rising from the buried upland floor through the partly denuded cover of lower Palaeozoic strata. This knob or ridge can be thought of as an ancient physiographic fossil, as it is an ancient monadnock having been preserved from destructive attacks of weather by burial under sea-floor deposits. It has been recently re-exposed through the erosion of its cover. The occurrence of the lake basins in the lowland belts on either side of the Niagara escarpment is an abnormal feature. Glacial erosion has formed them through the glacial drift obstructing the normal outlet valleys and to crustal warping in connection with or independent of the glacial sheet.

Lake Superior is unlike the other lakes. The greater part of its basin occupies a depression in the upland area, independent of the overlap of Palaeozoic strata. The western half of the basin occupies a trough of synclinal structure. The Great Lakes receive the drainage of a small peripheral land area, enclosed by a water-parting from the rivers that run to Hudson Bay or the Gulf of Saint Lawrence on the north and to the Gulf of Mexico on the south.

The three lakes of the middle group: Lake Michigan, Lake Huron and Lake Erie stand at practically the same level. Lake Michigan and Lake Huron are connected by the Straits of Mackinac with the Mackinac Bridge spanning the straits. Lake Huron and Lake Erie are connected by the St. Clair River and Detroit River, with the small Lake St. Clair between them. The land northeast of the rivers is undergoing a slow elevation. The Niagara River connecting Lake Erie and Lake Ontario, with a fall of 326 feet (99 m) (160 feet (49 m) at the cataract) in 30 miles (48 km), is thought to have been of recent origin, as an older river would have a mature valley. The original valley that is thought to have connected the two depressions through the Niagara Escarpment is thought to have been at the present route of the Welland Canal, and to have been completely filled with glacial drift. The same is true for the St. Lawrence, where there may not have been an original valley. The Ontarian River that was a precursor to Lake Ontario is thought to have drained westward, and the St. Lawrence drainage to have been created by subsidence due to the weight of the ice sheet.

Sign in to keep reading

6 more chapters are free with a Lably account.

More in Regions and countries