(2) Abrasion: When the glacier moves, the rock fragments frozen at the bottom of the glacier or the ice layer are ground and etched by the pressure of the upper glacier, which is called abrasion. Wear can form a polished surface with scratches on bedrock. Scratches or grooves are good evidence of glaciation, and their direction can be used to indicate the direction of glaciers.
(3) Ice wedge action: After repeated freezing and thawing, the volume of ice melt water contained in rock cracks rises and shrinks, which makes the rock strata break into pieces, or falls into glaciers from slopes on both sides and moves forward.
(4) Others: When meltwater enters the river, it often contains a lot of ice, which will have a strong impact to destroy the rocks on both banks of the downstream.
Processing action
A large number of loose debris generated by glacier intrusion and debris on the hillside will enter the glacier system and move with the glacier. These transported fragments are called moraines, which can be divided into different transport types according to their different positions in glaciers:
(1) moraine: moraine exposed on the surface of glacier.
(2) Internal moraine: moraine in glacier.
(3) Moraine: Moraine accumulates at the bottom of the glacier.
(4) lateral moraines: moraines are accumulated on both sides of the glacier.
(5) Middle moraine: After two glaciers meet, the adjacent side moraines merge into one, which is called the middle moraine.
(6) Terminal moraine: the moraine around the end of the glacier when it advances, which is called terminal moraine.
(7) Backward moraine: Because the glacier will have a short pause in the process of retreating, each pause will cause a backward moraine.
(8) Bubbles: The handling of glaciers can not only carry moraines to far places, but also carry huge rocks to very high places. These huge rocks are called boulders, and their lithology is completely different from that of the nearby bedrock.
Glaciers have strong carrying capacity, but relatively speaking, their translation capacity is poor.
build-up effect
Sandstones carried by glaciers are often thrown along the way. Therefore, after glaciers melt, materials transported in different forms will accumulate to form corresponding moraines. The so-called moraine refers to the non-layered ice deposits directly caused by glaciers. Ice deposits refer to substances directly deposited by glaciers, substances deposited by ice water, and substances deposited by glaciers in rivers and lakes.
Mooring substances in the ocean.