Weathering and Erosion Review

What is weathering?

The process of breaking rocks into smaller fragments (sediments) or changing the chemical composition of a rock.

What does mechanical weathering involve?

Physically breaking rocks into smaller pieces without changing their chemical composition.

What occurs during frost/ice wedging?

Water fills cracks in the rock, freezes and expands, then thaws and contracts, weakening the rock.

What is an example of frost/ice wedging?

Potholes in the roads.

What is wind abrasion?

Tiny particles of sand/dirt carried by the wind hit rocks and wear away their surface.

What causes water abrasion?

Moving water causes rock particles to rub against other particles, wearing away parts of the rock.

What is glacial abrasion?

Rock trapped in glacial ice rubs against the ground rocks, breaking or scarring both.

How do plants contribute to mechanical weathering?

Small plants grow in cracks of rocks and their roots can crack the rock as they grow.

How do animals contribute to mechanical weathering?

Animals dig into weak rocks or soil, exposing bedrock to water and air.

What is chemical weathering?

The chemical breakdown of rock by changing its mineral composition.

What is hydrolysis in the context of weathering?

Water reacts with minerals in a rock, changing and dissolving them.

What occurs during oxidation?

Water and oxygen react with metal elements in rocks, resulting in a chemical change.

What is carbonic acid and how does it affect weathering?

Slightly acidic water that dissolves calcium carbonate in rocks, creating features like caves.

What is acid rain?

Rain that contains acids, resulting from industrial gases or volcanic activity reacting with water vapor.

What role do plant acids play in weathering?

Certain plants release acids from their roots that help break down rocks.

What factors determine the rate/type of weathering?

Mineral/rock composition, surface exposure, and climate.

How does climate impact weathering?

Cold/dry climates favor mechanical weathering; warm/wet climates favor chemical weathering.

What is erosion?

The transportation of weathered rock or sediments from one location to another.

What are the four main agents of erosion?

Glaciers, gravity, running water, and wind.

What is deposition in the context of erosion?

Occurs when wind, water, ice, or gravity no longer has the energy to carry sediment, causing it to drop to the ground.

What caused the Dust Bowl in the 1930s?

Poor farming methods, removal of native grasses, drought, and strong winds.

What are some ways to reduce erosion?

Using windbreaks, contour farming, and not over-irrigating the soil.

What is soil composed of?

A mix of weathered rock and decomposing organic matter.

What are soil horizons?

Layers of soil grouped into distinct layers including A, B, and C horizons.

What is the A horizon in soil?

The humus layer (organic) known as topsoil.

What is the B horizon in soil?

The subsoil layer.

What is the C horizon in soil?

The weathered rock layer.

What is bedrock?

The solid rock layer beneath the soil horizons.

How does surface exposure affect weathering?

More surface exposed results in faster weathering of the rock.

What happens in climates favoring frost action?

Frost action works best in areas with widely fluctuating temperatures.

What was a significant consequence of the Dust Bowl?

One of the worst instances of wind erosion in American history.