Geography of Lake Superior

| |

The North American continent has a cluster of five lakes concentrated along the latitudes of 41 and 48 degrees North. They are known the Great Lakes. Four out of fives of these lakes are shared by the United States of America and Canada (only Lake Michigan is located completely within the United States of America).

One of those lakes is Lake Superior. Its own geography sets it apart from the other Great Lakes. 

The Westernmost and Northernmost of the Great Lakes

The North American Great Lakes span the distance of eastern Ontario and upstate New York to northeastern Minnesota and northwest Wisconsin. The westernmost limit of this lake is the city of Duluth, Minnesota.

Satellite image of the Great Lakes.  Source: NASA.
Satellite image of the Great Lakes. Source: NASA.

Lake Superior is the westernmost and northernmost of the five Great Lakes. Lake Superior is the only Great Lake that spans as far north as 48 degrees North parallels. No other North American Great Lake touches the 47 degree North parallel, except Lake Superior. 

Lake with the Highest Elevation of the Great Lakes

Lake Superior sits at an average altitude of 607.71 feet (183 meters) above sea level. This makes Lake Superior the lake with the highest elevation of the Great Lakes. 

How Lake Superior Got its Name

Superior’s name comes from the French language. French explorers traversed this lake and gave it the name “le Lac Supérieur”. This translates to “the upper lake”. Le Lac Supérieur would prove to be a fitting name for the northernmost and westernmost of the five Great Lakes. 

Long before French explorers came across Lake Superior, this region had long been inhabited by Ojibwe people. In the Ojibwe language, Lake Superior is called “Gichi-Gami”. This name means “great sea”. “Gichi-Gami” is a fitting name for another reason: size.

Largest Freshwater Lake in the World

Lake Superior is the largest of the Great Lakes. Its surface area is 31,700 square miles (82,000 square kilometers). When judging the lake by surface area, this makes it the largest freshwater lake in the world. It has a volume of 2,900 cubic miles (12,000 cubic kilometers), making it the third most voluminous in the world.

Miners Castle, Lake Superior.
Miners Castle, Lake Superior. Photo: Pictured Rocks National Lakeshore, NPS.

To understand how large Lake Superior is, the country of the Czech Republic has a land area of 29,825 square miles (77,247 square kilometers). The Czech Republic is smaller than Lake Superior based on surface area. 

Geography and Geology of Lake Superior

It is not only Lake Superior’s size and elevation that makes it stand apart. The geographic and geological features of its shoreline set it up from the other lakes.

Every Great Lake was formed out of the retreating of glaciers. This is true of Lake Superior. The creation of Lake Superior started out as a rift of large size billions of years prior. This rift is known as the Mid Continental Rift. Sediments would soon find themselves within the rift.

Generalized geologic map of the Midcontinent Rift, Lake Superior region, showing sedimentary, volcanic, and intrusive rocks and major and minor faults. The location of the Copperwood and White Pine mineral deposits are shown. Map: Jeff Mauk, U.S. Geological Survey. Public domain.
Generalized geologic map of the Midcontinent Rift, Lake Superior region, showing sedimentary, volcanic, and intrusive rocks and major and minor faults. The location of the Copperwood and White Pine mineral deposits are shown. Map: Jeff Mauk, USGS. Public domain.

During the Last Glacial Period, most of Canada and the northern parts of the United States of America were under the Laurentide ice sheet. This ice sheet would retreat. With the melting and retreating of the glaciers, this formed lakes out of the erosion of shales and softer sedimentary rocks.

The southern portions of the Great Lakes Basin have bedrock consisting of shales and sedimentary rocks. The waters that formed Lake Superior eroded the sediments and softer rocks within the Mid Continental Rift. What was left behind were igneous rocks, in particular basalt and granite. These rocks are from the Precambrian period. This is the result of volcanic activity that took place. The bedrock found along the Lake Superior shore is exposed, being more difficult to erode. Examples of this bedrock manifest itself in the cliffs and rocky shores found along Lake Superior. 

Islands of Lake Superior

Lake Superior has many islands. Some notable islands include the Apostle Islands, Isle Royale, and the Susie Islands. The Apostle Islands archipelago has 22 islands and is located off Wisconsin’s northern coast. Most of these islands comprise the Apostle Islands National Lakeshore.

Landsat 8 satellite image of the Apostle Islands on August 14, 2015. Source: NASA
Landsat 8 satellite image of the Apostle Islands on August 14, 2015. Source: NASA

East of Minnesota’s Arrowhead region is the Susie Islands archipelago. Thirteen islands make up this archipelago, located along the North Shore of Lake Superior. Another notable island is Isle Royale. It is the largest of Lake Superior’s islands. The entire island is Isle Royale National Park. 

Cities Along Lake Superior

Lake Superior being such a vast inland sea has played an important role in human and economic geography. Thunder Bay, Ontario and Duluth, Minnesota are the largest cities along Lake Superior. 

Duluth is home to the furthest inland ocean-going port in the world. The nearest ocean from Port of Duluth is 2,300 miles away. Ocean-going ships can access the port via the Great Lakes Waterway. Iron ore is a major resource in Minnesota, specifically in the Arrowhead region around Duluth. Duluth is a major transshipment center for iron ore.

Steel, grain, and wind turbine components are other products shipped from the Port of Duluth. Thunder Bay, like Duluth, is a major shipping center along Lake Superior. It is one of the largest ports in Canada. Grain, coal, and potash from western Canada are shipped from Thunder Bay. Mining equipment for the oilsands areas in Alberta are shipped into Thunder Bay and then transported by rail.

The deep waters of Lake Superior have made it an important shipping lane in North America. Lake Superior is connected to the rest of the St. Lawrence Seaway via the Great Lakes Waterway. 

Weather and Lake Superior

Ice span on Lake Superior, February 14, 2020.  Suomi NPP satellite, NASA.
Ice span on Lake Superior, February 14, 2020. Image: Suomi NPP satellite, NASA.

Lake Superior has also proven to be a place of storms. During the autumn months, particularly November, winds from the Arctic regions and Gulf of Mexico converge over the region. Lake Superior still has enough warmth left to create storms. One such storm proved to be especially tragic.  

On November 10, 1975, the famous “Gale Of November” occurred on Lake Superior. The SS Edmund Fitzgerald was carrying taconite iron ore from Duluth, Minnesota. The intended destination was Detroit. The ship was lost, sinking in the storm. All 29 of the ship’s crew died in the shipwreck as a result of the storm. Over 300 shipwrecks have taken place on Lake Superior.

Despite its importance for shipping, Lake Superior has fewer people living along its coasts than most of the other Great Lakes. Most of the Superior basin is covered in forests. Soils in the Lake Superior basin tend to be underdeveloped relative to the other lakes. The cool climate and poor soil quality is why there is far less agricultural output.

View of Lake Superior, Upper Peninsula of Michigan.
View of Lake Superior, Upper Peninsula of Michigan taken from a forested area. Photo: John J. Mosesso, USGS. Public domain.

Lake Superior has fewer dissolved nutrients in its waters relative to its size than the other Great Lakes. It is an oligotrophic lake and has far lower algal production, tending to be clearer than the other lakes.

This affects the kind of fish found in Lake Superior. Lake trout, among at least 80 species of fish, which are found in cold waters with low levels of dissolved oxygen, can be found in Lake Superior.

Lake Superior has clear water.  Photo: NPS.
Lake Superior’s clear water. Photo: NPS.

References

Carlowicz, M. (2016, August 28). Apostle islands national Lakeshore. NASA Earth Observatory. https://earthobservatory.nasa.gov/images/88639/apostle-islands-national-lakeshore

Gale of Nov. 9th, 1913 Great Lakes greatest?: Schooner days CXIII (113). (n.d.). https://images.maritimehistoryofthegreatlakes.ca/123087/data

Great Lakes ecoregion. (n.d.). National Oceanic and Atmospheric Administration. https://www.noaa.gov/education/resource-collections/freshwater/great-lakes-ecoregion

Lake Superior. (n.d.). Minnesota Department of Natural Resources. https://www.dnr.state.mn.us/lakesuperior/index.html

Related

Share:


Enter your email to receive the Geography Realm newsletter: