| Labrador Ice sheet | |
|---|---|
 | |
| Type | Continental |
| Location | Canadian Shield |
| Lowest elevation | Sea level |
| Terminus | North – Baffin ice sheet West – Keewatin ice sheet East – Atlantic Ocean South – Long Island, New York to the Great Lakes |
| Status | Gone |
The Labrador ice sheet was a major ice sheet that periodically covered large parts of North America during glacial periods over the last ~2.6 million years.
The Labrador Ice Sheet radiated from two focus points. The primary Quebec Dome, centered over the Ungava Peninsula. A second dome, called the Hudson Bay Dome was to the west on shore of Hudson Bay, near Churchill, Manitoba.
The Adirondack Mountains are a massif of mountains in Northeastern New York which form a circular dome approximately 160 miles (260 km) wide and covering about 5,000 square miles (13,000 km2). The region contains more than 100 peaks, including Mount Marcy, which is the highest point in New York at 5,344 feet (1,629 m). The Adirondack High Peaks, a traditional list of 46 peaks over 4,000 feet (1,200 m), are popular hiking destinations. There are over 200 named lakes with the number of smaller lakes, ponds, and other bodies of water reaching over 3,000. Among the named lakes around the mountains are Lake George, Lake Placid, and Lake Tear of the Clouds. The region has over 1,200 miles (1,900 km) of river.
The Wisconsin glaciation, also called the Wisconsin glacial episode, was the most recent glacial period of the North American ice sheet complex, peaking more than 20,000 years ago. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cordillera; the Innuitian ice sheet, which extended across the Canadian Arctic Archipelago; the Greenland ice sheet; and the massive Laurentide Ice Sheet, which covered the high latitudes of central and eastern North America. This advance was synchronous with global glaciation during the last glacial period, including the North American alpine glacier advance, known as the Pinedale glaciation. The Wisconsin glaciation extended from about 75,000 to 11,000 years ago, between the Sangamonian Stage and the current interglacial, the Holocene. The maximum ice extent occurred about 25,000–21,000 years ago during the last glacial maximum, also known as the Late Wisconsin in North America.
Ellef Ringnes Island is an uninhabited island and one of the Sverdrup Islands in the Qikiqtaaluk Region, Nunavut, Canada. A member of the Queen Elizabeth Islands and Arctic Archipelago, it is located in the Arctic Ocean, east of Borden Island, and west of Amund Ringnes Island. It has an area of 11,295 km2 (4,361 sq mi), making it the 69th largest island in the world and Canada's 16th largest island. Its highest mount is 260 m (850 ft).
The Laurentide ice sheet was a massive sheet of ice that covered millions of square miles, including most of Canada and a large portion of the Northern United States, multiple times during the Quaternary glaciation epochs, from 2.58 million years ago to the present.
The Cordilleran ice sheet was a major ice sheet that periodically covered large parts of North America during glacial periods over the last ~2.6 million years.
A Heinrich event is a natural phenomenon in which large groups of icebergs break off from the Laurentide ice sheet and traverse the Hudson Strait into the North Atlantic. First described by marine geologist Hartmut Heinrich, they occurred during five of the last seven glacial periods over the past 640,000 years. Heinrich events are particularly well documented for the last glacial period but notably absent from the penultimate glaciation. The icebergs contained rock mass that had been eroded by the glaciers, and as they melted, this material was dropped to the sea floor as ice rafted debris forming deposits called Heinrich layers.
Pingos are intrapermafrost ice-cored hills, 3–70 m (10–230 ft) high and 30–1,000 m (98–3,281 ft) in diameter. They are typically conical in shape and grow and persist only in permafrost environments, such as the Arctic and subarctic. A pingo is a periglacial landform, which is defined as a non-glacial landform or process linked to colder climates. It is estimated that there are more than 11,000 pingos on Earth, with the Tuktoyaktuk peninsula area having the greatest concentration at a total of 1,350. There is currently remarkably limited data on pingos.
Horsenden Hill is a hill and open space, located between the Perivale, Sudbury, and Greenford areas of West London. It is in the London Borough of Ealing, close to the boundary with the London Borough of Brent. It is one of the higher eminences in the local area, rising to 85 m (276 ft) above sea level, and the summit forms part of the site of an ancient hillfort. It is the site of a trig point, TP4024.
The Boreal Shield Ecozone, as defined by the Commission for Environmental Cooperation (CEC), is the largest ecozone in Canada. Covering 1.8 million square kilometres it covers almost 20% of Canada's landmass, stretching from northern Saskatchewan to Newfoundland.
The Tyrrell Sea, named after Canadian geologist Joseph Tyrrell, is another name for prehistoric Hudson Bay, namely as it existed during the retreat of the Laurentide Ice Sheet.
Pingo Canadian Landmark, also known as Pingo National Landmark, is a natural area protecting eight pingos near Tuktoyaktuk, Northwest Territories. It is in a coastal region of the Arctic Ocean which contains approximately 1,350 Arctic ice dome hills—approximately one quarter of the world's pingos.
Lake Bassano was a proglacial lake that formed in the Late Pleistocene during the deglaciation of south-central Alberta by the impoundment of a re-established drainage system and addition of glacial meltwater. It is associated with the development of through-flowing drainage within the Red Deer River basin in particular, and the South Saskatchewan drainage network in general. Approximately 7,500 square kilometres (2,900 sq mi) of the Bassano basin is covered with lacustrine sediments. These sediments are bordered by the topographically higher Buffalo Lake Moraine to the west, the Suffield Moraine to the east and the Lethbridge Moraine to the south.
Lowther Island lies within the Arctic Archipelago in the Qikiqtaaluk Region of northern Canada's territory of Nunavut. It is one of the mid-channel islands in the western sector of Barrow Strait. Bathurst Island and Cornwallis Island are to the north, while Prince of Wales Island is to the south. The island is clustered within a group of uninhabited islands. It is 15.5 mi (24.9 km) northeast of Young Island, separated by the Kettle Passage, a shipping route, and 13 mi (21 km) southeast of Garrett Island, separated by Hayes Channel.
Omars, are a distinctive type of glacial erratic that consists of dark siliceous greywacke and exhibits prominent rounded, often deep, hemispherical voids and pits. The hemispherical voids and pits result from the selective dissolution of carbonate concretions within the greywacke. The greywacke is identifiable by its low metamorphic grade and the 10–40% rock fragments, distinctive volcanic clasts, and spherical carbonate concretions that it contains. Omars are typically rounded and range in size from pebbles to boulders. Their rounded shape, whether found in glacial tills or glacial-fluvial (outwash) gravels, indicate that they were eroded from pre-existing littoral or fluvial deposits. Omars are typically found associated with granules and pebbles of oolitic jasper that were transported from the Belcher Islands in Hudson Bay, Canada.
The greenside darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It inhabits swift riffles in the eastern United States and southern Ontario.
New England is a region in the North Eastern United States consisting of the states Rhode Island, Connecticut, Massachusetts, New Hampshire, Vermont, and Maine. Most of New England consists geologically of volcanic island arcs that accreted onto the eastern edge of the Laurentian Craton in prehistoric times. Much of the bedrock found in New England is heavily metamorphosed due to the numerous mountain building events that occurred in the region. These events culminated in the formation of Pangaea; the coastline as it exists today was created by rifting during the Jurassic and Cretaceous periods. The most recent rock layers are glacial conglomerates.
The Missinaibi Formation is a Late Pleistocene geologic formation in the Hudson Bay Lowlands in Northern Ontario, Canada. The formation lies within Missinaibi Provincial Park.
The Goldthwait Sea was a sea that emerged during the last deglaciation, starting around 13,000 years ago, covering what is now the Gulf of Saint Lawrence and surrounding areas. At that time, the land had been depressed under the weight of the Laurentide Ice Sheet, which was up to 2 kilometres (1.2 mi) thick. Areas on the Anticosti Island and low-lying regions of Quebec and the Maritimes bordering the Saint Lawrence were below sea level. As the land rebounded over the next 3,000 years, despite rising sea levels the sea retreated to roughly the present boundaries of the Gulf.
The Keewatin ice sheet was a major ice sheet that periodically covered large parts of North America during glacial periods over the last ~2.6 million years.
The Baffin ice sheet was the most northerly portion of the Laurentide Ice Sheet, centered in the Foxe Basin between Baffin Island and the Melville Peninsula north of Hudson Bay. Blocked from a southward flow by the Keewatin and Labrador Ice sheets, it moved north and eastward across Baffin Island into the Baffin Sound. Two smaller ice domes formed along the island chain of the Sound as the Barnes Dome, Penny Dome and the Amadjuak Dome.
| Cenozoic Era (present–66.0 Ma) |
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| Mesozoic Era (66.0–252 Ma) |
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| Paleozoic Era (252–539 Ma) |
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| Proterozoic Eon (539 Ma–2.5 Ga) |
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| Archean Eon (2.5–4 Ga) | |||||||||||||
| Hadean Eon (4–4.6 Ga) | |||||||||||||
ka = kiloannum (thousand years ago); Ma = megaannum (million years ago); Ga = gigaannum (billion years ago). See also: Geologic time scale •  Geologyportal •  Worldportal | |||||||||||||
