Search results
Results From The WOW.Com Content Network
Most lakes in the world occupy basins scoured out by glaciers. Glacial motion can be fast (up to 30 metres per day (98 ft/d), observed on Jakobshavn Isbræ in Greenland) [1] or slow (0.5 metres per year (20 in/year) on small glaciers or in the center of ice sheets), but is typically around 25 centimetres per day (9.8 in/d). [2]
Glacial plucking both exploits pre-existing fractures in the bedrock and requires continued fracturing to maintain the cycle of erosion. [4] Glacial plucking is most significant where the rock surface is well jointed or fractured or where it contains exposed bed planes, as this allows meltwater and clasts to penetrate more easily. [2]
[1] [2] They can be up to 10 meters wide and are typically found on ice sheets and flat areas of a glacier in a region of transverse crevasses. Moulins can reach the bottom of the glacier, hundreds of meters deep, [3] [4] [5] or may only reach the depth of common crevasse formation (about 10–40 m) where the stream flows englacially. [6]
Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. [40] The bed's temperature, roughness and softness define basal shear stress, which in turn defines whether movement of the glacier will be accommodated by motion in the sediments, or if it will be able to slide.
Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods, respectively. The Earth is currently in such an interglacial period of the Quaternary glaciation, with the Last Glacial Period of the Quaternary having ended approximately 11,700 years ago.
Franz Josef Glacier in New Zealand Features of a glacial landscape. Glacier morphology, or the form a glacier takes, is influenced by temperature, precipitation, topography, and other factors. [1] The goal of glacial morphology is to gain a better understanding of glaciated landscapes and the way they are shaped. [2]
Basal sliding is the act of a glacier sliding over the bed due to meltwater under the ice acting as a lubricant.This movement very much depends on the temperature of the area, the slope of the glacier, the bed roughness, the amount of meltwater from the glacier, and the glacier's size.
If the glacial action erodes through, a spillway (or col) forms; Horn: a sharp peak connecting multiple glacier intersections, made up of multiple arêtes. Valley step: an abrupt change in the longitudinal slope of a glacial valley; Hanging Valleys: Formed by glacial meltwater eroding the land partially, often accompanied by a waterfall. [2]