What is the difference between plucking and abrasion?
Plucking occurs when rocks and stones become frozen to the base or sides of the glacier and are plucked from the ground or rock face as the glacier moves. This leaves behind a jagged landscape. Abrasion occurs when rocks and stones become embedded in the base and sides of the glacier.
What is plucking in the process of glacier?
Plucking: The bedrock beneath a glacier often has cracks in it that were there before it was ever covered in ice. These cracks may grow beneath the glacier, and eventually join with one another. When this happens, entire chunks of rock can break off and be carried away by the ice.
What characteristics might a geologist use to differentiate glacial till from river sediment?
What characteristics might a geologist use to differentiate glacial till from river sediment? a. Glacial drift is finer-grained than river sediment.
Which features are formed by glacial erosion?
U-shaped valleys, hanging valleys, cirques, horns, and aretes are features sculpted by ice. The eroded material is later deposited as large glacial erratics, in moraines, stratified drift, outwash plains, and drumlins. Varves are a very useful yearly deposit that forms in glacial lakes.
What is the process of plucking?
Definition: Plucking is a process of erosion that occurs during glaciation. As ice and glaciers move, they scrape along the surrounding rock and pull away pieces of rock which causes erosion.
What does abrasion create?
Abrasion can crush smaller grains or particles and remove grains or multigrain fragments, but the removal of larger fragments is classified as plucking (or quarrying), the other major erosion source from glaciers. Plucking creates the debris at the base or sides of the glacier that causes abrasion.
What is the process of abrasion?
Abrasion is the physical process of rubbing, scouring, or scraping whereby particles of rock (usually microscopic) are eroded away by friction.
What is the difference between glacial till and glacial outwash?
A till plain is composed of unsorted material (till) of all sizes with much clay, an outwash plain is mainly stratified (layered and sorted) gravel and sand. The till plain has a gently undulating to hilly surface; the outwash is flat or very gently undulating where it is a thin veneer on the underlying till.
Which geological feature is caused mainly by glacial erosion?
Moraines, which are linear deposits of glacial sediments (till) left by the glacier along its edges, can form a dam at the end of a tarn. Often, a series of moraines will form as glaciers recede. These can act as water dams, and result in strings of lakes called rock basin lakes or paternoster lakes.
What are two landforms formed by glaciers?
Cirques, tarns, U-shaped valleys, arêtes, and horns. The heads of most glacial valleys are occupied by one or several cirques (or corries). A cirque is an amphitheatre-shaped hollow with the open end facing down-valley.
What are the three main agents of erosion?
Most erosion is performed by liquid water, wind, or ice (usually in the form of a glacier). If the wind is dusty, or water or glacial ice is muddy, erosion is taking place.
Why is abrasion important?
Abrasion has been identified as an important erosive process, particularly on shore platforms (Sunamura, 1976; Robinson 1977a, b, c; Kennedy and Beban, 2005; Blanco-Chao et al., 2007). Abrasion operates where sediments that are as hard or harder than the underlying bedrock accumulate and are moved by wave action.