Push moraine

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The Luneburg Heath seen from the Wilseder Berg in northern Germany. The Luneburg Heath consists of pushed moraines made from Neogene sand deposits. These form nutrient-poor soils and are generally shrublands covered in heaths. Luneburger Heide 007.jpg
The Lüneburg Heath seen from the Wilseder Berg in northern Germany. The Lüneburg Heath consists of pushed moraines made from Neogene sand deposits. These form nutrient-poor soils and are generally shrublands covered in heaths.

A push moraine or pushed moraine is in geomorphology a moraine (a landform formed by glacial processes) that forms when the terminus advance of a lowland glacier pushes unstratified glacial sediment into a pile or linear ridge in front of it. A push moraine is identified by its ability to push sediment upwards from its original horizontal position. Push moraines are limited in size by the advance of a glacier front and its tendency to shear over the top of any ridge large enough to resist the movement of ice. Pushed moraines generally occur in low, flat plains at higher latitudes and were formed during the glacial stages of the Quaternary ice age. They can be up to 100 km long and several hundreds of metres in height.

Pushed moraines can be found in the North American plains, in Siberia and in Northern Europe. They were formed during cool, glacial stages, when glaciers advanced and covered large parts of North America and Eurasia. In some regions pushed moraines of more than one glacial stage can be recognised, or different generations from a single glacial phase. Since new glacial advances tend to destroy older pushed moraines, most were formed during the last (110,000 to 10,000 years ago) or second-last (238,000 to 128,000 years ago) glacial advances. Today push moraines can be found anywhere an advancing glacier is pushing sediment into a ridge at the terminus.

The largest push moraine in the world is the Dirt Hills in southern Saskatchewan, Canada. The hills are located about 60 kilometres south-east of city of Moose Jaw, along the Missouri Coteau. [1]

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Related Research Articles

Moraine Glacially formed accumulation of unconsolidated debris

A moraine is any accumulation of unconsolidated debris, sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour. Lateral moraines are those formed at the side of the ice flow, and terminal moraines were formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines and medial moraines.

Wisconsin glaciation North American glacial ice sheet

The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. 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 approximately 75,000 to 11,000 years ago, between the Sangamonian Stage and the current interglacial, the Holocene. The maximum ice extent occurred approximately 25,000–21,000 years ago during the last glacial maximum, also known as the Late Wisconsin in North America.

Last Glacial Period Period of major glaciations of the northern hemisphere (115,000–12,000 years ago)

The Last Glacial Period (LGP) occurred from the end of the Eemian to the end of the Younger Dryas, encompassing the period c. 115,000 – c. 11,700 years ago. The LGP is part of a larger sequence of glacial and interglacial periods known as the Quaternary glaciation which started around 2,588,000 years ago and is ongoing. The definition of the Quaternary as beginning 2.58 million years ago (Mya) is based on the formation of the Arctic ice cap. The Antarctic ice sheet began to form earlier, at about 34 Mya, in the mid-Cenozoic. The term Late Cenozoic Ice Age is used to include this early phase.

Lake Passaic

Lake Passaic was a prehistoric proglacial lake that existed in northern New Jersey in the United States at the end of the last ice age approximately 19,000–14,000 years ago. The lake was formed of waters released by the retreating Wisconsin Glacier, which had pushed large quantities of earth and rock ahead of its advance, blocking the previous natural drainage of the ancestral Passaic River through a gap in the central Watchung Mountains. The lake persisted for several thousand years as melting ice and eroding moraine dams slowly drained the former lake basin. The effect of the lake's creation permanently altered the course of the Passaic River, forcing it to take a circuitous route through the northern Watchung Mountains before spilling out into the lower piedmont.

Outwash plain Plain formed from glacier sediment that was transported by meltwater.

An outwash plain, also called a sandur, sandr or sandar, is a plain formed of glaciofluvial deposits due to meltwater outwash at the terminus of a glacier. As it flows, the glacier grinds the underlying rock surface and carries the debris along. The meltwater at the snout of the glacier deposits its load of sediment over the outwash plain, with larger boulders being deposited near the terminal moraine, and smaller particles travelling further before being deposited. Sandurs are common in Iceland where geothermal activity accelerates the melting of ice flows and the deposition of sediment by meltwater.

Würm glaciation

The Würm glaciation or Würm stage, usually referred to in the literature as the Würm, was the last glacial period in the Alpine region. It is the youngest of the major glaciations of the region that extended beyond the Alps themselves. Like most of the other ice ages of the Pleistocene epoch, it is named after a river, in this case the Würm in Bavaria, a tributary of the Amper. The Würm ice age can be dated to about 115,000 to 11,700 years ago, but sources differ about the dates, depending on whether the long transition phases between the glacials and interglacials are allocated to one or other of those periods. The average annual temperatures during the Würm ice age in the Alpine Foreland were below −3 °C. That has been determined from changes in the vegetation, as well as differences in the facies.

Till plain

Till plains are an extensive flat plain of glacial till that forms when a sheet of ice becomes detached from the main body of a glacier and melts in place, depositing the sediments it carried. Ground moraines are formed with melts out of the glacier in irregular heaps, forming rolling hills. Till plains are common in areas such as the Midwestern United States, due to multiple glaciation events that occurred in the Holocene epoch. During this period, the Laurentide Ice Sheet advanced and retreated during the Pleistocene epoch. Till plains created by the Wisconsin glaciation cover much of the Midwest, including North Dakota, South Dakota, Indiana, Minnesota, Wisconsin, Iowa, Illinois, and northern Ohio.

Glacial landform Landform created by the action of glaciers

Glacial landforms are landforms created by the action of glaciers. Most of today's glacial landforms were created by the movement of large ice sheets during the Quaternary glaciations. Some areas, like Fennoscandia and the southern Andes, have extensive occurrences of glacial landforms; other areas, such as the Sahara, display rare and very old fossil glacial landforms.

Glacial lake Lake formed by a melted glacier

A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land, and then melts, filling the depression created by the glacier.

Riss glaciation

The Riss glaciation, Riss Glaciation, Riss ice age, Riss Ice Age, Riss glacial or Riss Glacial is the second youngest glaciation of the Pleistocene epoch in the traditional, quadripartite glacial classification of the Alps. The literature variously dates it to between about 300,000 to 130,000 years ago and 347,000 to 128,000 years ago. It coincides with the Saale glaciation of North Germany. The name goes back to Albrecht Penck and Eduard Brückner who named this cold period after the river Riss in Upper Swabia in their three-volume work Die Alpen im Eiszeitalter published between 1901 and 1909.

Terminal moraine Type of moraine that forms at the terminal of a glacier

A terminal moraine, also called end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge of the ice, is driven no further and instead is deposited in an unsorted pile of sediment. Because the glacier acts very much like a conveyor belt, the longer it stays in one place, the greater the amount of material that will be deposited. The moraine is left as the marking point of the terminal extent of the ice.

Fluvio refers to things related to rivers and glacial refers to something that is of ice. Fluvio-glacial refers to the meltwater created when a glacier melts. Fluvio-glacial processes can occur on the surface and within the glacier. The deposits that happen within the glacier are revealed after the entire glacier melts or partially retreats. Fluvio-glacial landforms and erosional surfaces include: outwash plains, kames, kame terraces, kettle holes, eskers, varves, and proglacial lakes.

Glacial history of Minnesota

The glacial history of Minnesota is most defined since the onset of the last glacial period, which ended some 10,000 years ago. Within the last million years, most of the Midwestern United States and much of Canada were covered at one time or another with an ice sheet. This continental glacier had a profound effect on the surface features of the area over which it moved. Vast quantities of rock and soil were scraped from the glacial centers to its margins by slowly moving ice and redeposited as drift or till. Much of this drift was dumped into old preglacial river valleys, while some of it was heaped into belts of hills at the margin of the glacier. The chief result of glaciation has been the modification of the preglacial topography by the deposition of drift over the countryside. However, continental glaciers possess great power of erosion and may actually modify the preglacial land surface by scouring and abrading rather than by the deposition of the drift.

Fluvioglacial landforms are those that result from the associated erosion and deposition of sediments caused by glacial meltwater. These landforms may also be referred to as glaciofluvial in nature. Glaciers contain suspended sediment loads, much of which is initially picked up from the underlying landmass. Landforms are shaped by glacial erosion through processes such as glacial quarrying, abrasion, and meltwater. Glacial meltwater contributes to the erosion of bedrock through both mechanical and chemical processes.

Kankakee Outwash Plain

The Kankakee Outwash Plain is a flat plain interspersed with sand dunes in the Kankakee River valley in northwestern Indiana and northeastern Illinois of the United States. It is just south of the Valparaiso Moraine and was formed during the Wisconsin Glaciation. As the glacier, stopped at the Valparaiso Moraine, melted, the meltwater was carried away to the outwash plain. On the south side of the moraine, where the elevation drops, the meltwaters eroded away valleys, carrying sand and mud with them. As the muddy meltwater reached the valley where the slope lessened, the water slowed, depositing the sand on the outwash plain. This created a smooth, flat, and sandy plain. Before its draining, the Kankakee Marsh, located on the outwash plain, was one of the largest freshwater marshes in the United States.

The glacial series refers to a particular sequence of landforms in Central Europe that were formed during the Pleistocene glaciation beneath the ice sheets, along their margins and on their forelands during each glacial advance.

Tiefwarensee Ice Age Trail

The Tiefwarensee Ice Age Trail runs around the Tiefwarensee lake on the northeastern perimeter of the town of Waren (Müritz) in the district of Mecklenburgische Seenplatte in the German state of Mecklenburg-Western Pomerania. The ten-kilometre-long path may be negotiated on foot or by bicycle. It is element D8 of the Mecklenburg Ice Age Landscape Geopark.

Harbor Hill Moraine Northern of two ridges along the "backbone" of Long Island, NY, USA

The Harbor Hill Moraine, in the geography of Long Island, forms the northern of two ridges along the "backbone" of Long Island.

Lake Kankakee

Lake Kankakee formed 14,000 years before present (YBP) in the valley of the Kankakee River. It developed from the outwash of the Michigan Lobe, Saginaw Lobe, and the Huron-Erie Lobe of the Wisconsin glaciation. These three ice sheets formed a basin across Northwestern Indiana. It was a time when the glaciers were receding, but had stopped for a thousand years in these locations. The lake drained about 13,000 YBP, until reaching the level of the Momence Ledge. The outcropping of limestone created an artificial base level, holding water throughout the upper basin, creating the Grand Kankakee Marsh.

The Dirt Hills Hills in Saskatchewan

The Dirt Hills and neighbouring Cactus Hills, are an arcuate moraine and the largest glacial push in the world. The hills were formed during the deglaciation of the last ice age about 10,000 years ago. They are located in the southern region of the Canadian province of Saskatchewan, east of Old Wives Lake and about 60 kilometres south-east of Moose Jaw and are part of the Bearpaw Formation within Palliser's Triangle and the Great Plains ecoregion.

References

  1. George, Ashlyn. "5 hidden gems not to be missed in Saskatchewan". Saskatoon StarPhoenix. Retrieved 27 October 2021.