Weathering and Erosion Notes

Weathering

The breaking down of rocks and minerals into smaller pieces by natural forces.

Physical/Mechanical Weathering

The process of breaking down rocks into smaller pieces without changing their chemical composition.

Chemical Weathering

The process of breaking down rocks through chemical reactions that change their composition.

Frost Wedging

Water enters cracks in rocks, freezes, expands, and breaks the rocks apart.

Abrasion in Weathering

The process where rocks are worn down by contact with other rocks or particles.

Plant Weathering

Roots grow into rock crevices, exerting pressure that breaks rocks apart.

Upward Expansion/Exfoliation

Rocks expand and crack when overlying pressure is removed, such as erosion of surface layers.

Hydrolysis in Chemical Weathering

The reaction between water and minerals, forming new minerals like clay. Example: Feldspar reacting with water to form clay minerals.

Oxidation in Chemical Weathering

The reaction between oxygen and minerals, often resulting in rust. Example: Iron in rocks reacting with oxygen to form iron oxide (rust).

Frost Wedging Climates

Frost wedging occurs in cold climates where temperatures frequently fluctuate above and below freezing.

Factors Impacting Weathering Rate

Factors like climate, rock type, surface area, and time affect the rate.

Erosion

The process by which weathered materials are transported from one location to another.

Karst Topography Factors

The presence of soluble rocks like limestone, water, and acidic conditions.

Agents of Erosion

Water, wind, gravity, and glaciers.

Water as an Agent of Erosion

Water transports sediments, forming landscapes like river valleys.

Wind as an Agent of Erosion

Wind carries particles, shaping landscapes like sand dunes.

Gravity as an Agent of Erosion

Gravity causes materials to move downhill, forming landslides.

Glaciers as an Agent of Erosion

Glaciers carve out valleys and transport rocks.

Soil Formation

Soil forms through the breakdown of rocks and the accumulation of organic matter.

Humus

Decayed organic material found in soil.

Residual Soil

Soil that remains above its parent rock.

Transported Soil

Soil that has been moved from its place of origin by erosion.

Soil Horizons

O Horizon: Organic matter. A Horizon: Topsoil, rich in organic material. B Horizon: Subsoil, rich in minerals leached from above. C Horizon: Weathered rock fragments.