Till or glacial till is unsorted glacial sediment.
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type. Temperate grassland regions include the Pampas of Argentina, Brazil and Uruguay, and the steppe of Ukraine, Russia and Kazakhstan. Lands typically referred to as "prairie" tend to be in North America. The term encompasses the area referred to as the Interior Lowlands of Canada, the United States, and Mexico, which includes all of the Great Plains as well as the wetter, hillier land to the east.
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.
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.
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 formed by the Wisconsin glaciation cover much of the Midwest, including North Dakota, South Dakota, Indiana, Minnesota, Wisconsin, Iowa, Illinois, and northern Ohio.
The Driftless Area, a topographical and cultural region in the Midwestern United States, comprises southwestern Wisconsin, southeastern Minnesota, northeastern Iowa, and the extreme northwestern corner of Illinois.
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.
Savanna Portage State Park is a state park of Minnesota, USA, established in 1961 to preserve the historic Savanna Portage, a difficult 6-mile (9.7 km) trail connecting the watersheds of the Mississippi River and Lake Superior. The portage trail crosses a drainage divide separating the West Savanna River, which drains to the Mississippi River and the Gulf of Mexico, from the East Savanna River, which flows in an opposite direction to the Saint Louis River, Lake Superior and the Great Lakes, and the Saint Lawrence River to the Atlantic Ocean.
A tunnel valley is a U-shaped valley originally cut under the glacial ice near the margin of continental ice sheets such as that now covering Antarctica and formerly covering portions of all continents during past glacial ages. They can be as long as 100 km (62 mi), 4 km (2.5 mi) wide, and 400 m (1,300 ft) deep.
The geology of Minnesota comprises the rock, minerals, and soils of the U.S. state of Minnesota, including their formation, development, distribution, and condition.
The geology of Illinois includes extensive deposits of marine sedimentary rocks from the Palaeozoic, as well as relatively minor contributions from the Mesozoic and Cenozoic. Ice age glaciation left a wealth of glacial topographic features throughout the state.
Glacial River Warren, also known as River Warren, was a prehistoric river that drained Lake Agassiz in central North America between about 13,500 and 10,650 BP calibrated years ago. A part of the uppermost portion of the former river channel was designated a National Natural Landmark in 1966.
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.
The River Warren Falls was a massive waterfall on the glacial River Warren initially located in present-day Saint Paul, Minnesota, United States. The waterfall was 2700 feet (823 m) across and 175 feet (53 m) high.
The proglacial lakes of Minnesota were lakes created in what is now the U.S. state of Minnesota in central North America in the waning years of the last glacial period. As the Laurentide Ice Sheet decayed at the end of the Wisconsin glaciation, lakes were created in depressions or behind moraines left by the glaciers. Evidence for these lakes is provided by low relief topography and glaciolacustrine sedimentary deposits. Not all contemporaneous, these glacial lakes drained after the retreat of the lobes of the ice sheets that blocked their outlets, or whose meltwaters fed them. There were a number of large lakes, one of which, Glacial Lake Agassiz, was the largest body of freshwater known to have existed on the North American continent; there were also dozens of smaller and more transitory lakes filled from glacial meltwater, which shrank or dried as the ice sheet retreated north.
The Valparaiso Moraine is a recessional moraine that forms an immense U around the southern Lake Michigan basin in North America. It is the longest moraine. It is a band of hilly terrain composed of glacial till and sand. The Valparaiso Moraine forms part of the Saint Lawrence River Divide, bounding the Great Lakes Basin. It begins near the border of Wisconsin and Illinois and extends south through Lake, McHenry, Cook, DuPage and Will counties in Illinois, and then turns southeast, going through northwestern Indiana. From this point, the moraine curves northeast through Lake, Porter, and LaPorte counties of Indiana into Michigan. It continues into Michigan as far as Montcalm County.
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, its 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.
Lake Monongahela was a proglacial lake in western Pennsylvania, West Virginia, and Ohio. It formed during the Pre-Illinoian ice epoch when the retreat of the ice sheet northwards blocked the drainage of these valleys to the north. The lake formed south of the ice front continued to rise until it was able to breach a low divide near New Martinsville, West Virginia. The overflow was the beginning of the process which created the modern Ohio River valley.
Lake Circle was a glacial lake that formed during the late Pleistocene epoch along the Redwater River in eastern Montana. After the Laurentide Ice Sheet retreated, glacial ice melt accumulated in the basin surrounded by the ridges of the preglacial valley and the retreating glacier. Southwest of Nickwall are the remnants of a broad abandoned valley with long side slopes. The valley runs north from Redwater Creek to the Missouri River. The bottom is poorly drained and about 1 mile (1.6 km) in width. It lies 2,015 to 2,020 feet above the sea level and 40 to 50 feet above the Missouri River bottomland. The upland slopes are extensive, clear and flat. The valleys surrounding it are dissected with V-shaped coulees. The difference between the Redwater valley and those around it reflect stream erosion vs. lake sedimentation. The drift in the valleys, appears to be as left by the glacier in the previously created valleys. Using the dating of lake deposits near Great Falls, Montana, the Havre lobe of the Laurentide Ice Sheet dammed the ancestral Missouri River during the late Wisconsin Glacial Period.
Lake Chouteau was a glacial lake formed during the late Pleistocene along the Teton River. After the Laurentide Ice Sheet retreated, water melting off the glacier accumulated between the Rocky Mountains and the ice sheet. The lake drained along the front of the ice sheet, eastward towards the Judith River and the Missouri River.
