Flute (glacial)
Encyclopedia
A glacial flute is a landform created by the movement of a glacier
around a boulder. They are long ridges on the ground parallel to the movement. Examples can be found in many places including Iceland, Alaska and Canada.
As glaciers move along the surface of the earth, rocks are slowly mixed in with the ice. Rocks may reach the bottom of the glacier and begin to scrape along the earth. Eventually boulder sized rocks become lodged in the ground. Once the boulder is in place, the glacier flows around it. As a result, a cavity is formed on the down slope side of the boulder. This cavity is then filled with sediments such as till
and outwash. Similar cavities can also be formed as the glacier moves over bedrock outcrops or bed irregularities which also may form flutes.
These mounds are usually only a couple of metres high but hundreds of metres long. They are named flutes as their long and narrow shape resembles the musical instrument.
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
around a boulder. They are long ridges on the ground parallel to the movement. Examples can be found in many places including Iceland, Alaska and Canada.
As glaciers move along the surface of the earth, rocks are slowly mixed in with the ice. Rocks may reach the bottom of the glacier and begin to scrape along the earth. Eventually boulder sized rocks become lodged in the ground. Once the boulder is in place, the glacier flows around it. As a result, a cavity is formed on the down slope side of the boulder. This cavity is then filled with sediments such as till
Till
thumb|right|Closeup of glacial till. Note that the larger grains in the till are completely surrounded by the matrix of finer material , and this characteristic, known as matrix support, is diagnostic of till....
and outwash. Similar cavities can also be formed as the glacier moves over bedrock outcrops or bed irregularities which also may form flutes.
These mounds are usually only a couple of metres high but hundreds of metres long. They are named flutes as their long and narrow shape resembles the musical instrument.