Introduction
The largest world supply of freshwater comes from the Great Lakes. In the United States, this source provides more than 90% of the freshwater consumed in the region (National Oceanic and Atmospheric Administration, 2015). It is also said to contain about 18% of the total freshwater found in the world. More than 40 million Americans, as well as Canadians, draw their freshwater from the Great Lakes. On average, the total area covered by this fascinating feature is more than 94, 000 square miles. This paper aims to discuss the formation of this magnificent geological feature.
Formation of the Great Lakes
According to Calkin and Bern (1985), the area that is currently occupied by the Great Lakes was initially covered with glacial ice. Besides, two plates were fused beneath this ice. Gradually, these plates split apart, and a midcontinent rift was created. In between the rift, there emerged a valley on which a basin formed with time. This basin later became Lake Superior. The Saint Lawrence rift was created when a second separation occurred.
Another valley with two basins emerged, and this is where the current Lakes Ontario and Erie lie. The glacial ice that covered the area that is currently occupied by the Great Lakes is said to be more than a kilometer thick (Michigan Environmental Education Curriculum, 2014). Massive amounts of soil were being moved during the creation of the valleys. However, it is believed that the melting of the glacier started in North America as it moved to Canada. Large holes were left behind by the melting ice. As a result, the water that filled these basins formed the Great Lakes.
Among the Lakes that form the interconnected Great Lakes are Lake Nipissing, Lake Algonquin, and Lake Chippewa. It is said that Lake Algonquin was formed 11,000 years ago (Hough, 1958). Initially, this lake covered an area of about 100,000 square miles. Its formation occurred when glacier ice known as Laurentide melted while moving north.
On the other hand, Lake Nippising was formed when glacier ice known as Wisconsin melted. Lake Chippewa was formed when unspecified ice retreated creating the Seaway at St. Lawrence. Other lakes that form part of the Great Lakes include Lake Michigan, Lake Superior, and Lake Huron. All the three lakes were at one time temporarily joined into Lake Nippising. Later on, Lake Michigan gradually drained River Illinois. This is where the present Chicago stands. On the other hand, Lake Huron drained the Ottawa River and St. Lawrence River as well. One can thus argue that the Great Lakes were formed as a result of glacial ice retreating and advancing over an extended time.
Currently, the Great Lakes contain 6 quadrillion gallons of freshwater (University of Wisconsin, 2014). Their uniqueness is derived from the fact that all the lakes are linked in terms of their basins. This results in a drainage basin that is continuous with a length of about 2, 212 miles. This path is significant in that it provides direct shipping access to ships going to the Atlantic Ocean through the Seaway at St. Lawrence. The deepest point at the Great Lakes is found at Lake Superior where a depth of 1, 333 feet is found (Karrow, 1984).
Formation of the Great Lakes brought with it several resources. For example, the region around Lake Superior has provided the sole source of ore to North America. This has in turn improved the economy of this region to greater heights. Large processors of iron and steel are located on the shores of Lakes Michigan, Ontario, Superior, and Erie because these lakes provide abundant and reliable sources of freshwater that are needed to process iron and steel (University of Wisconsin, 2014).
This area provides an avenue for sports as well as commercial fishing. As a result, more than a billion dollars are collected as revenues from such activities each year. Besides, a lot of people are directly and indirectly employed in the Great Lakes related projects. Each year, close to $62 billion of wages are generated by the Great Lakes. The formation of the Great Lakes has truly transformed areas close to the region by providing clean, freshwater to millions of people in addition to providing job opportunities to many.
Conclusion
The Great Lakes were formed as a result of massive glacier ice melting through retreating and advancing over an extended period. Two major drifts happened, thereby creating valleys that gave way to basins. These basins were later filled with the melted water to form the various lakes that are part of the Great Lakes. These lakes include Lakes Superior, Ontario, Erie, Michigan, Nippising, Algonquin, Chippewa, and Huron. The formation of these Lakes has transformed the economy of the surrounding region. Many jobs have been created where more than $62 billion is generated in the form of wages each year around Great Lakes. The St. Lawrence Seaway provides a channel through which ships can transport bulk goods from the region to the Atlantic Ocean.
References
Calkin, P. E., & Bern, H. F. (1985). Evolution of the Erie-basin great lakes. Evolution of the Great Lakes, 30, 149-170.
Hough, J. L. (1958). Geology of the Great Lakes. Champaign, IL: University of Illinois Press.
Karrow, P. F. (1984). Quaternary stratigraphy and history: Great Lakes – St. Lawrence region. Quaternary Stratigraphy of Canada, 24, 84-100.
Michigan Environmental Education Curriculum. (2014). Great Lakes formation. Web.
National Oceanic and Atmospheric Administration. (2015). About our Great Lakes: Introduction. Web.
University of Wisconsin. (2014). The Great Lakes: How they were made. Web.