Lake Champlain Geology- present

Lake Champlain is located on the Champlain Valley between the Green Mountains of Vermont and the Adirondack Mountains of New York state. It flows north and is drained by the Richelieu River, which in turn flows into the Saint Lawrence River at Sorel-Tracy, Quebec. Lake Champlain’s major feeders are Otter Creek, the Winooski, Lamoille and Missisquoi Rivers in Vermont and New York’s Ausable, Chazy, Boquet and Saranac Rivers. Lake Champlain also receives water from the 32 (51 km) mile long Lake George via the LaChute River. This means that Lake Champlain receives water not only from the northwestern slopes of the Green Mountains and the northeastern peaks of the Adirondacks, but it also drains the north and west slopes of Massachusetts’ Berkshire Mountains. Lake Champlain is connected to the Hudson River by the Champlain Canal.

Lake Champlain’s geology is very interesting. The Champlain Valley is considered part of the Great Appalachian Valley, which reaches from Quebec to Alabama. It is a physiographic section (geomorphic, or physiographic, regions are broad-scale subdivisions based on terrain texture, rock type, and geologic structure and history) of the Saint Lawrence Valley, which is, in turn, part of the larger Appalachian physiographic division.

Lake Champlain is one of many large lakes that are found in an arc from Labrador through the northern United States and into the Northwest Territories of Canada.  Although smaller than any of the Great Lakes, it is the largest freshwater lake in North America after the Great Lakes. Lake Champlain typically varies seasonally from 95 to 101 feet (29 to 30 m) above mean sea level.

Between 20,000 and 10,000 years ago the Champlain Basin was part of a great inland sea that was a temporary inlet of the Atlantic Ocean, a para-tropical sub sea, or epeiric sea, called the Champlain Sea. It was 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. This sea extended to the west of present day Ottawa, Ontario in Canada.

Modern evidence of the sea can be seen in the form of whale fossils, (beluga, fin whales and bowhead whales) and marine shells that have been found in Vermont  and 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. From Mount Pakenham, Ontario, the viewable ancient coastline to the northeast is roughly 25 miles (40 km) away and is known today as the Eardley Escarpment; part of the Gatineau Hills in the province of Quebec.