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Because ice can flow faster where it is thicker, the rate of glacier-induced erosion is directly proportional to the thickness of overlying ice. Consequently, pre-glacial low hollows will be deepened and pre-existing topography will be amplified by glacial action, while nunataks , which protrude above ice sheets, barely erode at all – erosion ...
Areas where the ice is most easily lifted (i.e. areas with thinner overlying ice sheets) are lifted first. Hence the water may move up the terrain underlying the glacier if it moves toward areas of lower overlying ice. [7] As water collects, additional ice is lifted until a release path is created. [8]
Sognefjord in Norway, the second longest fjord in the world, shows characteristic overdeepening.. Overdeepening is a characteristic of basins and valleys eroded by glaciers.An overdeepened valley profile is often eroded to depths which are hundreds of metres below the lowest continuous surface line (the thalweg) along a valley or watercourse.
Eskers form in ice tunnels within or under a glacier, as shown in Figure 1, and are composed of the sediment deposits from the streams that occupy these tunnels. [37] Eskers may also form from supra-glacial streams that cut into the crevasses of the glacier. After the ice has melted away the stream deposits are left remaining as long mounded ...
The high confining pressures on the glacier bed from the weight of the overlying glacial ice fills the elongate cavity by squeezing water-soaked till into it. [ 1 ] [ 3 ] [ 4 ] [ 7 ] As a glacier melts back and recedes, it exposes the till bed of the glacier and the long, low ridges of till that have been molded upon it.
' study of ice ') is the scientific study of glaciers, or, more generally, ice and natural phenomena that involve ice. Glaciology is an interdisciplinary Earth science that integrates geophysics , geology , physical geography , geomorphology , climatology , meteorology , hydrology , biology , and ecology .
A subduction mechanism is a key to the ice tectonics hypothesis on Europa. For subduction to occur, convection within or below the ice crust must exert stresses that exceed the strength of the overlying ice crust. [5] But to hold a tenable tectonics hypothesis, one must explain how ice sinks below the surface. [5]
The path of an esker is governed by its water pressure in relation to the overlying ice. Generally, the pressure of the ice was at such a point that it would allow eskers to run in the direction of glacial flow, but force them into the lowest possible points such as valleys or river beds, which may deviate from the direct path of the glacier.