What is the Geologic structure of St.Lawrence Lowlands?
Answers
Answer:
The Great Lakes–St. Lawrence Lowlands, or simply St. Lawrence Lowlands, is a physiographic region of Canada that comprises a section of southern Ontario bounded on the north by the Canadian Shield and by three of the Great Lakes—Lake Huron, Lake Erie, and Lake Ontario—and extends along the Saint Lawrence River to the Strait of Belle Isle[1] and the Atlantic Ocean. The lowlands comprise three sub-regions that were created by intrusions from adjacent physiographic regions—the West Lowland, the Central Lowland, and the East Lowland.[1] The West Lowland includes the Niagara Escarpment, extending from the Niagara River to the Bruce Peninsula and Manitoulin Island.[1] The Central Lowland stretches between the Ottawa River and the Saint Lawrence River.[1] The East Lowland includes Anticosti Island, Îles de Mingan, and extends to the Strait of Belle Isle. It is one of the most densely populated, prosperous and productive regions in Canada. Major urban areas include Quebec City, Montreal, Trois-Rivières, Saint-Hyacinthe, Cornwall, Ontario, Brockville, Ottawa/Gatineau, and Pembroke. The Lowlands are in the traditional territories of the Mohawk, the Algonquian and Iroquoian peoples, and the Cree. The Lowlands were covered by surficial deposits left by ice sheets following the Pleistocene glaciations.[1] It is the smallest of Canada's seven physiographic regions—the Canadian Shield, the Hudson Bay Lowland, the Arctic Lands, the Interior Plains, the Cordillera, and the Appalachian Uplands—distinguished by topography and geology.[1] The boundaries of the area largely reflect that of the Mixedwood Plains Ecozone, the smallest of Canada's fifteen terrestrial ecozones.
Answer:
Central Lowland
The St. Lawrence Lowlands include a "mix of bedrock outcrops and deeper marine and lacustrine clay deposits". It is "underlain by carbonate-rich" limestone Paleozoic sedimentary rock. In the north it is bounded by the Laurentian Highlands.