Mass movement & Glacial erosion Sections 3.1 & 3.3

Mass Movement

Mass Movement Erosion is the process by which natural forces move weathered rock and soil from one place to another. Gravity, moving water, glaciers, waves, and wind are all agents (causes) of erosion. Sediments are pieces of rock or soil, or the remains of plants and animals. Deposition occurs when the agents of erosion deposit, or lay down, sediments. Weathering, erosion, and deposition act together in a never-ending cycle that wears down and builds up Earth’s surface.

Mass Movement Gravity is the force that pulls you downhill. Mass movement moves sediments downhill. It can be fast or slow. Different types of mass movement include landslides, mudflows, slump, and creep. Landslides= rock and soil move quickly down a steep slope. Mudflow= rapid downhill movement of water, rock, and soil. Slump= a mass of rock and soil suddenly moves down a slope in one large mass. Creep= very slow downhill movement of rock and soil.

Glacial Erosion A glacier is any large mass of ice that moves slowly over land. Glaciers can only form in an area where more snow falls than melts. Continental glaciers are glaciers that cover much of a continent or large island and flow in all directions as they move. An ice age is a time in Earth’s history when glaciers covered much of the surface.

Glacial Erosion A valley glacier is a long, narrow glacier that forms when snow and ice build up high in a mountain valley. Gravity constantly pulls a glacier downhill. As a glacier flows over the land, it picks up rocks in a process called plucking. This can move huge boulders. Abrasion is the grinding away of rock by other rock particles carried in water, ice, and wind.

Glacial Deposition When a glacier melts, it deposits the sediments it eroded from the land, creating various landforms. A glacial deposit in a mound or ridge is a moraine.