Champlain Sea
The Champlain Sea was a temporary inlet of the Atlantic Ocean, a paratropical subsea or epeiric sea created by the retreating glaciers during the close of the last ice age. The Sea once included lands in what are now the Canadian provinces of Quebec and Ontario, as well as parts of the American states of New York and Vermont.[1]
The mass of ice from the continental ice sheets had depressed the rock beneath it over millennia, causing it to rebound once the ice melted. This process is gradual and known as isostatic rebound. While the rock was still depressed, the Saint Lawrence and Ottawa River valleys, as well as modern Lake Champlain, were below sea level and flooded once the ice no longer prevented the ocean from flowing into the region.[2]
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 Lake Champlain and somewhat farther west than the site of Ottawa, Ontario. The remaining glaciers fed the sea during that time, making it more brackish than typical seawater. It is estimated that the sea was as much as 150 metres (490 ft) above the level of today's Saint Lawrence and Ottawa Rivers.[citation needed]
Modern evidence of the sea can be seen in the form of whale fossils, (belugas, fin whales[3], and bowhead whales) and marine shells[4] that have been found near the cities of Ottawa, Ontario, and Montreal, Quebec, the existence of ancient shorelines in the former coastal regions, and the presence of Leda clay deposits dotting the region.[5] From the Petawawa fault zone at Mount Pakenham, Ontario, the viewable ancient coastline to the northeast is roughly 40 kilometres (25 mi) away and is known today as the Eardley Escarpment. The Eardley Escarpment is known locally as the Gatineau Hills; part of the Mattawa fault at the South-Eastern edge of the Ottawa-Bonnechere Graben, in the province of Québec. The Gatineau Hills are situated at the Foothills of the Laurentian Mountains.[citation needed]
[edit] References
[edit] External links
- History of the Champlain Sea.
- Charlotte, The Vermont Whale
- 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
