Saint David's Buried Gorge
Encyclopedia
Saint David's Buried Gorge is an ancient pre-glacial river bed that existed 22,800 years ago on the present-day Niagara Peninsula
. The ancient Saint David's River once flowed through this area prior to the advance of the Wisconsin Glacier during the last glacial period. When the glacier retreated 12,000 years ago, the gorge and river valley were filled in with glacial silt
and rocks. Approximately 4,200 years ago, the Niagara River
intersected the buried gorge in the course of Niagara Falls
receding toward Lake Erie
. When the river encountered the soft glacial silt that filled the gorge, the river rapidly changed course to fill the ancient gorge and wash out most of the silt. This lead to the formation of the Niagara Whirlpool
. The Niagara River reclaimed the gorge and currently flows through part of the ancient gorge. The other part of the ancient gorge extends into Lake Ontario
at a different point than the Niagara River. The gorge is estimated to be 4000 ft (1,219.2 m) long, 1000 ft (304.8 m) wide, and 300 ft (91.4 m) deep.
Niagara Peninsula
The Niagara Peninsula is the portion of Southern Ontario, Canada lying between the south shore of Lake Ontario and the north shore of Lake Erie. It stretches from the Niagara River in the east to Hamilton, Ontario in the west. The population of the peninsula is roughly 1,000,000 people...
. The ancient Saint David's River once flowed through this area prior to the advance of the Wisconsin Glacier during the last glacial period. When the glacier retreated 12,000 years ago, the gorge and river valley were filled in with glacial silt
Rock flour
Rock flour, or glacial flour, consists of fine-grained, silt-sized particles of rock, generated by mechanical grinding of bedrock by glacial erosion or by artificial grinding to a similar size...
and rocks. Approximately 4,200 years ago, the Niagara River
Niagara River
The Niagara River flows north from Lake Erie to Lake Ontario. It forms part of the border between the Province of Ontario in Canada and New York State in the United States. There are differing theories as to the origin of the name of the river...
intersected the buried gorge in the course of Niagara Falls
Niagara Falls
The Niagara Falls, located on the Niagara River draining Lake Erie into Lake Ontario, is the collective name for the Horseshoe Falls and the adjacent American Falls along with the comparatively small Bridal Veil Falls, which combined form the highest flow rate of any waterfalls in the world and has...
receding toward Lake Erie
Lake Erie
Lake Erie is the fourth largest lake of the five Great Lakes in North America, and the tenth largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded on the north by the...
. When the river encountered the soft glacial silt that filled the gorge, the river rapidly changed course to fill the ancient gorge and wash out most of the silt. This lead to the formation of the Niagara Whirlpool
Niagara Whirlpool
The Niagara Whirlpool is a natural whirlpool along the Niagara River located along the U.S.-Canadian border between New York and Ontario. The whirlpool is located in the Niagara Gorge, downstream from Niagara Falls...
. The Niagara River reclaimed the gorge and currently flows through part of the ancient gorge. The other part of the ancient gorge extends into Lake Ontario
Lake Ontario
Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot language, ontarío means...
at a different point than the Niagara River. The gorge is estimated to be 4000 ft (1,219.2 m) long, 1000 ft (304.8 m) wide, and 300 ft (91.4 m) deep.