Everything about Lake Superior totally explained
Lake Superior is the largest of the five
Great Lakes of
North America. It is bounded to the north by
Ontario,
Canada and
Minnesota,
USA, and to the south by the
U.S. states of
Wisconsin and
Michigan. It is the
largest freshwater lake in the world by surface area and is the world's
third-largest freshwater lake by volume.
Name
In the
Ojibwe language, the lake is called
Gichigami, meaning "big water". It is also known as "Gitche Gumee" as recorded by
Henry Wadsworth Longfellow in
The Song of Hiawatha. Lake Superior is also referred to as "Gitche Gumee" in the song "
The Wreck of the Edmund Fitzgerald", by
Gordon Lightfoot.
The lake was named
le lac supérieur, or "Upper Lake," in the seventeenth century by
French explorers because it was located above
Lake Huron.(Nute, 1946)
Hydrography
Lake Superior is the largest
freshwater lake in the world by surface area.
Lake Baikal in
Russia is larger by volume, as is
Lake Tanganyika. The
Caspian Sea, while larger than Lake Superior in both surface area and volume, is saline; though presently isolated, in the past, it has been repeatedly connected to, and isolated from, the
Mediterranean via the
Black Sea.
Lake Superior has a surface area of —which is larger than
South Carolina. It has a maximum length of and maximum breadth of . Its average depth is with a maximum depth of . Waves well over have been recorded.
Until approximately 1887, the natural hydraulic conveyance through the St. Marys River rapids determined outflow from Lake Superior. By 1921, development in support of transportation and hydropower resulted in gates, locks, power canals, and other control structures completely spanning St. Marys rapids. The regulating structure is known as the Compensating Works, and is operated according to a regulation plan known as Plan 1977-A. The current water levels, including diversions of water from the
Hudson Bay watershed, are governed by the
International Lake Superior Board of Control which was established in 1914 by the
International Joint Commission.
Tributaries and outlet
The lake is fed by over 200 rivers. The largest include the
Nipigon River, the
St. Louis River, the
Pigeon River, the
Pic River, the
White River, the
Michipicoten River, the
Brule River and the
Kaministiquia River. Lake Superior drains into
Lake Huron by the
St. Marys River. The rapids on the river necessitate the
Sault Locks (pronounced "soo"), a part of the
Great Lakes Waterway, to move boats over the height difference from Lake Huron.
Geography
The largest island in Lake Superior is
Isle Royale in the state of
Michigan; this island itself carries a number of lakes, some of which contain islands. Other large famous islands include
Madeline Island in the state of
Wisconsin and
Michipicoten in the province of
Ontario.
The larger cities on Lake Superior include: the twin ports of
Duluth, Minnesota and
Superior, Wisconsin;
Thunder Bay, Ontario;
Marquette, Michigan; and the two cities of
Sault Ste. Marie, in
Michigan and in
Ontario. Duluth, at the western tip of Lake Superior, is the most inland point on the
Saint Lawrence Seaway and the most inland port in the world.
Among the scenic places on the lake are: the
Apostle Islands National Lakeshore;
Isle Royale National Park;
Porcupine Mountains Wilderness State Park;
Tahquamenon Falls State Park;
Pukaskwa National Park;
Lake Superior Provincial Park;
Grand Island National Recreation Area;
Sleeping Giant (Ontario);and
Pictured Rocks National Lakeshore.
Climate
Lake Superior's size creates a localized
oceanic or
maritime climate (more typically seen in locations like
Nova Scotia). The water surface's slow reaction to temperature changes, seasonally ranging between 32°-55°F (0°-13°C) around 1970, helps to moderate surrounding air temperatures in the
summer and
winter, and creates
lake effect snow in colder months. The hills and
mountains that border the lake form a bowl, which holds moisture and fog, particularly in the fall. The lake's surface temperature has risen by 4.5°F (2.5°C) since 1979, which is attributed to
global warming.
Geology
The rocks of Lake Superior's North Shore date back to the early history of the earth. During the
Precambrian (between 4.5 billion and 540 million years ago),
magma forcing its way to the surface created the intrusive
granites of the
Canadian Shield. These ancient granites can be seen on the North Shore today. It was during the
Penokean orogeny, that many valuable metals were deposited. The region surrounding the lake has proved to be rich in
minerals.
Copper,
iron,
silver,
gold and
nickel are or were the most frequently
mined. Examples include the
Hemlo gold mine near
Marathon, copper at Point Mamainse, silver at
Silver Islet, and uranium at Theano Point.
The mountains steadily eroded, depositing layers of
sediments which compacted and became
limestone,
dolostone,
taconite, and the
shale at
Kakabeka Falls.
The continent was later
riven, creating one of the deepest rifts in the world. The lake lies in this long-extinct
Mesoproterozoic rift valley, the
Midcontinent Rift. Magma was injected between layers of sedimentary rock, forming
diabase sills. This hard diabase protects the layers of sedimentary rock below, forming the flat-topped mesas in the
Thunder Bay area.
Amethyst formed in some of the cavities created by the Midcontinent Rift, and there are several Amethyst mines in the Thunder Bay area.
Lava erupted from the rift and formed the black
basalt rock of Michipicoten Island, Black Bay Peninsula, and St. Ignace Island.
During the
Wisconsin glaciation 10,000 years ago, ice covered the region at a thickness of . The land contours familiar today were carved by the advance and retreat of the ice sheet. The retreat left gravel, sand, clay, and boulder deposits. Glacial meltwaters gathered in the Superior basin creating
Lake Minong, a precursor to Lake Superior. Without the immense weight of the ice, the land
rebounded, and a drainage outlet formed at
Sault Ste. Marie, which would become known as
St. Mary's River.
History
The first people came to the Lake Superior region 10,000 years ago after the retreat of the glaciers in the last
Ice Age. They are known as the
Plano, and they used stone-tipped spears to hunt caribou on the northwestern side of
Lake Minong.
The next documented people were known as the Shield Archaic (c. 5000-500
B.C.). Evidence of this culture can be found at the eastern and western ends of the Canadian shore. They used bows and arrows, dugout canoes, fished, hunted, mined copper for tools and weapons, and established trading networks. They are believed to be the direct ancestors of the
Ojibwe and
Cree.
The Laurel people (c. 500 B.C. to
A.D. 500) developed
seine net fishing, evidence being found at rivers around Superior such as the Pic and Michipicoten.
Another culture known as the Terminal Woodland Indians (c. A.D. 900-1650) has been found. They were
Algonkian people who hunted, fished and gathered berries. They used snow shoes, birch bark canoes and conical or domed lodges. At the mouth of the Michipicoten River, nine layers of encampments have been discovered. Most of the
Pukaskwa Pits were likely made during this time.
The
Anishinabe, also known as the
Ojibwe or
Chippewa, have inhabited the Lake Superior region for over five hundred years, and were preceded by the
Dakota,
Fox,
Menominee, Nipigon, Noquet, and
Gros Ventres. They called Lake Superior
Anishnaabe Chi Gaming, or "the Ojibwe's Ocean". After the arrival of Europeans, the
Anishinabe made themselves the middle-men between the French fur traders and other Native peoples. They soon became the dominant Indian nation in the region: they forced out the
Sioux and
Fox and won a victory against the
Iroquois west of
Sault Ste. Marie in 1662. By the mid-1700s, the
Ojibwe occupied all of Lake Superior's shores.
In the 1700s, the fur trade in the region was booming, with the
Hudson's Bay Company (HBC) having a virtual monopoly. In 1783, however, the
North West Company (NWC) was formed to rival HBC. The NWC built forts on Lake Superior at
Grand Portage, Nipigon, the Pic River, the Michipicoten River, and
Sault Ste. Marie. But by 1821, with competition taking too great a toll on both, the companies merged under the Hudson's Bay Company name.
Many
towns around the lake are either current or former
mining areas, or engaged in processing or
shipping. Today,
tourism is another significant
industry as the sparsely populated Lake Superior country, with its rugged shorelines and
wilderness, attracts
tourists and
adventurers.
Shipping
Lake Superior has been an important link in the
Great Lakes Waterway, providing a route for the transportation of
iron ore and other mined and manufactured materials. Large cargo vessels called
lake freighters, as well as smaller ocean-going
freighters, transport these commodities across Lake Superior.
Shipwrecks
The last major shipwreck on Lake Superior was that of
SS Edmund Fitzgerald in 1975.
According to an old sailor's tale, Lake Superior never gives up her dead. This is because of the low temperature of the water, estimated at under on average around 1970. This is alluded to poetically in
Gordon Lightfoot's famous ballad, "
The Wreck of the Edmund Fitzgerald".
Storms that claimed multiple ships include the Mataafa Storm on
November 28,
1905, and the
Great Lakes Storm of 1913.
In August 2007, wreckage was found of the
Cyprus, a ore carrier which sank during a Lake Superior storm in of water. All but Charles G. Pitz of the
Cyprus’ 23 crew perished on
October 11,
1907. The ore carrier sank in Lake Superior on its second voyage, whilst hauling
iron ore from
Superior, Wisconsin, to
Buffalo, New York. Built in
Lorain, Ohio, the
Cyprus was launched
August 17,
1907.
Ecology
Although part of a single system, each of the Great Lakes is different. In volume, Lake Superior is the largest. It is also the deepest and coldest of the five. Superior could contain all the other Great Lakes and three more Lake Eries. Because of its size, Superior has a
retention time of 191 years.
Superior's water levels temporarily reached a new low in September 2007, slightly less than the previous record low in 1926. However, the water levels soon returned within a few days.
According to a study by professors at the University of Minnesota Duluth, Lake Superior may have warmed faster than its surrounding climate. These warmer temperatures can actually lead to more snow in the
lake effect snow belts along the shores of the lake, especially in the
Upper Peninsula of
Michigan.
Over sixty species of fish have been found in Lake Superior, among them:
bloater,
brook trout,
brown trout,
burbot,
carp,
chinook salmon,
coho salmon,
freshwater drum,
lake herring,
lake sturgeon,
lake trout,
lake whitefish,
longnose sucker,
muskellunge,
northern pike,
pumpkinseed,
pink salmon,
rainbow smelt,
rainbow trout,
rock bass,
round goby,
round whitefish,
ruffe,
sea lamprey,
smallmouth bass,
walleye,
white perch,
white sucker, and
yellow perch.
Lake Superior has fewer dissolved nutrients relative to its size compared to the other Great Lakes and so is less productive in terms of fish populations. This is a result of the underdeveloped soils found in its relatively small watershed. However, nitrate concentrations in the lake have been continuously rising for more than a century. They are still much lower than levels considered dangerous to human health, but this steady, long-term rise is an unusual record of environmental nitrogen buildup. It may relate to anthropogenic alternations to the regional
Nitrogen Cycle, but researchers are still unsure of the causes of this change to the lake's ecology. As for other Great Lakes, fish populations have also been impacted by the accidental or intentional introduction of foreign species such as the
sea lamprey and eurasian
ruffe. Accidental introductions have occurred in part due to the removal of natural barriers to navigation between the Great Lakes. Overfishing has also been a factor in the decline of fish populations.
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