Geography: Weathering and Rock Types

These flashcards cover key concepts about weathering types and rock classifications according to the lecture notes.

Weathering

The breaking down of rocks into smaller pieces due to exposure to different elements.

Types of Weathering

Mechanical (Physical), Chemical, and Biological weathering.

Mechanical Weathering

Physical breaking down of rock without changing their chemical composition.

Chemical Weathering

The breakdown of rocks through chemical composition/reactions, altering their chemical makeup.

Biological Weathering

Weathering caused by living organisms, such as plants and animals, that produce weak acids.

Igneous Rock

Formed from cooled and solidified magma; can be extrusive (volcanic) or intrusive (platonic).

Sedimentary Rock

Formed from fragments of other rocks compressed and hardened in layers (strata).

Metamorphic Rock

Formed from existing rocks changed by heat or pressure.

Freeze-thaw Weathering

Occurs in cold climates when water freezes in rock cracks, expanding and causing the rock to crack.

Exfoliation Weathering

Peeling off outer layers of rock due to thermal expansion and contraction.

Salt Crystal Growth

Saltwater penetrates rock surfaces, and crystals from evaporation exert pressure, causing disintegration.

Oxidation

The reaction of oxygen with minerals, particularly iron, leading to rust formation (iron oxide).

Carbonation (Acid Rain)

Rainwater containing carbon dioxide forms carbonic acid, which dissolves limestone and other carbonate rocks.

Hydrolysis

Water reacts with silicate minerals to form clays, altering the rock structure.

Factors Affecting Weathering

Climate, rock type, rock structure, vegetation, relief, and human activity impact the rate of weathering.

Hoff's Law

The rate of chemical weathering increases 2-3 times for each 10°C temperature rise up to 60°C.