Weathering Erosion Deposition Weathering is Weathering is the

Weathering, Erosion, & Deposition

Weathering is. . �Weathering is the breaking down of rocks into smaller and smaller pieces. �There are two types of weathering: � Mechanical Weathering � Chemical Weathering

Mechanical Weathering � Mechanical weathering is the breakdown of rock by physical means. � Some examples are: � Ice (Ice wedging/frost action is a series of freezing and thawing) � Abrasion (wearing away of rock by the mechanical action of other rocks) � Wind, Water, and Gravity are different forms of abrasion.

Chemical Weathering � Chemical Weathering is when rocks break down as a result of chemical reactions causing the composition of rocks to change. � Some examples are � Acid (found in water, precipitation or lichens) � Air (Oxygen reacts with iron in a process called Oxidation which forms Rust).

Rate of Weathering �Some rocks and minerals are more resistant to weathering, while others experience weathering more quickly. �Weathering happens more quickly in hot and wet climates. �Climate and rock type are the most important factors in the rate of weathering. �Weathering happens more quickly when there is more surface area. � For example, a pile of pebbles will weather more quickly than one large boulder.

Erosion �Erosion is the process through which soil and sediment are transported from one place to another. �Erosion is primarily responsible for the formation of river systems.

Wind Erosion �Wind erosion occurs when wind blows over sand. The sand is deposited when the wind hits an obstacle. � The process of wind erosion is called deflation. � The movement of wind erosion is a bouncing movement called saltation.

Wave Erosion & Glacial Erosion �Wave erosion occurs along shorelines. �Glacial erosion is the mass movement of glaciers.

Erosion and Gravity �Mass movement is the movement of material down a slope through gravity. � Examples: Landslide, Mudslide, Creep, Slump �Mass movement can occur quickly (landslide, rock falls) or slowly (creep).

Preventing Erosion �Soil is valuable because living things need it and fertile soil takes a long time to create. �To prevent erosion of valuable soil, we can plants to help hold the soil in place. � If plants are removed, a situation like the dust bowl in the 1930’s could take place. �Farmers will also leave the stalks of previous year’s crops to help hold the soil in place.

Deposition �Deposition is the process through which soil and sediment is dropped off or deposited. � Two examples of where this occurs are on beaches and at river deltas.