The Champlain Sea (french: Mer de Champlain) was a prehistoric inlet of the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

into the

North American continent North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, created by the retreating

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at La ...

s during the closure of the last glacial period. The inlet once included lands in what are now the Canadian provinces of

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

and

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

, as well as parts of the American states of New York and

Vermont Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...

Origins

The mass of ice from the continental ice sheets had depressed the rock beneath it over millennia. At the end of the last glacial period, while the rock was still depressed, the Saint Lawrence and Ottawa River valleys, as well as modern

Lake Champlain Lake Champlain ( ; french: Lac Champlain) is a natural freshwater lake in North America. It mostly lies between the US states of New York and Vermont, but also extends north into the Canada, Canadian province of Quebec. The New York portion of t ...

, at that time the

Lake Vermont Lake Vermont, also called Glacial Lake Vermont, was a temporary lake created by the retreating glaciers during the close of the last ice age. The lake once included land in the Canadian province of Quebec and the American states Vermont and New Y ...

, were below sea level and flooded with rising worldwide sea levels, once the ice no longer prevented the ocean from flowing into the region. As the land gradually rose again, in the process known as

isostatic rebound Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound ...

, the sea coast gradually retreated to its current location. The sea lasted from about 13,000 years ago to about 10,000 years ago and was continuously shrinking during that time, since the rebounding continent was slowly rising above sea level. At its peak, the sea extended inland as far south as

and somewhat farther west than the city of Ottawa, Ontario, and farther up the Ottawa River past Pembroke. The remaining glaciers fed the sea during that time, making it more

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

than typical seawater. It is estimated that the sea was as much as above the level of today's Saint Lawrence and Ottawa Rivers.Barnett, P.J. 1988. History of the northwestern arm of the Champlain Sea. Pp 25–36 in Gadd, N.R. (ed.) ''The Late Quaternary Development of the Champlain Sea Basin''. Geological Association of Canada, Special Paper 36. Map 5.

Geological evidence

The best evidence of this former sea is the vast clay plain deposited along the Ottawa and St. Lawrence Rivers. This resulted in distinctive forest types, and large wetlands. Other modern evidence of the sea can be seen in the form of fossils of whales (

beluga The beluga whale (/bɪˈluːɡə/) (Delphinapterus leucas) is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus Delphinapterus. It is also known as the wh ...

fin whale The fin whale (''Balaenoptera physalus''), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a cetacean belonging to the parvorder of baleen whales. It is the second-longest species of ce ...

s, and bowhead whales),

walruses The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the fami ...

and other pinnipeds, and marine shells that have been found near the cities of Ottawa, Ontario, and

Montreal Montreal ( ; officially Montréal, ) is the second-most populous city in Canada and most populous city in the Canadian province of Quebec. Founded in 1642 as '' Ville-Marie'', or "City of Mary", it is named after Mount Royal, the triple ...

, Quebec. There are also fossils of oceanic fish such as

capelin The capelin or caplin (''Mallotus villosus'') is a small forage fish of the smelt family found in the North Atlantic, North Pacific and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin ...

. The Sea also left ancient raised shorelines in the former coastal regions, and the

Leda clay Quick clay, also known as Leda clay and Champlain Sea clay in Canada, is any of several distinctively sensitive glaciomarine clays found in Canada, Norway, Russia, Sweden, Finland, the United States and other locations around the world. The cla ...

deposits in areas of deeper water. The northern shore of the lake was in southern Quebec where outcrops of the Canadian Shield form Eardley Escarpment. This escarpment still has distinctive plants that may date back to the era when the sea existed.Brunton, D. and J.D. Lafontaine. 1974. An unusual escarpment flora in Western Quebec. The Canadian Field-Naturalist 88(3):337–344. The Eardley Escarpment is known locally as the

Gatineau Hills The Gatineau Hills (french: Collines de la Gatineau) are a geological formation in Canada that makes up part of the southern tip of the Canadian Shield, and acts as the northern shoulder of the Ottawa Valley. They are also the foothills of th ...

. It is part of the Mattawa fault at the southeastern edge of the

Ottawa-Bonnechere Graben The Ottawa-Bonnechere Graben (also known as the Ottawa Graben) is a geological structure that coincides with a wide topographic depression extending from near Montréal through Ottawa. It is part of the Saint Lawrence rift system that also inclu ...

, in

Eastern Ontario Eastern Ontario (census population 1,763,186 in 2016) (french: Est de l'Ontario) is a secondary region of Southern Ontario in the Canadian province of Ontario which lies in a wedge-shaped area between the Ottawa River and St. Lawrence River. It s ...

and the

Outaouais Outaouais (, ; also commonly called The Outaouais) is a region of western Quebec, Canada. It includes the city of Gatineau, the municipality of Val-des-Monts and the Papineau region. Geographically, it is located on the north side of the Ottaw ...

region of

, more commonly known as the

Ottawa Valley The Ottawa Valley is the valley of the Ottawa River, along the boundary between Eastern Ontario and the Outaouais, Quebec, Canada. The valley is the transition between the Saint Lawrence Lowlands and the Canadian Shield. Because of the surroun ...

References

External links

History of the Champlain Sea

Charlotte, The Vermont Whale
* https://web.archive.org/web/20070513190043/http://www.lesaventuresdupatrimoine.com/joly/gardiens/gar14.html * http://www.civilization.ca/cmc/archeo/kichisibi/champlain/f3-0.htm * http://www.ggl.ulaval.ca/personnel/bourque/s3/retrait.glaces.html {{Authority control Natural history of Ontario Natural history of Quebec Natural history of New York (state) Natural history of Vermont Pleistocene Seas of the Atlantic Ocean Last Glacial Period Glacial lakes of the United States Lake Champlain Seas of Canada

Origins

Geological evidence

See also

References

Further reading

External links