M2 Subtopic 2 Flashcards
External processes that occur on or near the Earth’s surface. They are driven by external forces such as solar energy and gravity
Exogenic Processes
Internal processes that originate within the Earth. They are driven by internal forces such as heat from the Earth’s interior and gravitational energy
Endogenic Process
The process by which rocks and minerals break down into smaller particles
through physical, chemical, and biological means
Weathering
Three Types of Weathering
Physical (Mechanical) Weathering
Chemical Weathering
Biological Weathering
Involves the breakdown of rocks and minerals into smaller pieces without changing their chemical composition
Physical Weathering (Mechanical Weathering)
Water seeps into cracks, freezes, expands, and eventually breaks the rock apart. Common in cold climates
Freeze-Thaw (Frost Wedging)
Rocks expand when heated and contract when cooled. Repeated temperature changes can cause the rock to crack
Thermal Expansion
Rocks and particles scrape against each other, causing them to wear
down. Common in windy areas and riverbeds
Abrasion
Layers of rock peel off due to pressure release or thermal expansion
Exfoliation
Involves the chemical alteration of minerals within rocks, leading to their breakdown
Chemical Weathering
Water reacts with minerals to form new minerals and soluble salts. For example, feldspar in granite reacts with water to form clay minerals
Hydrolysis
Minerals react with oxygen, often leading to rust formation. Common in rocks containing iron.
Oxidation
Carbon dioxide dissolved in water forms carbonic acid, which reacts with minerals like limestone, causing them to dissolve
Carbonation
Minerals dissolved directly in water, such as halite (rock salt) dissolving in rainwater
Solution
Involves the breakdown of rocks by living organisms
Biological Weathering
Roots grow into cracks in rocks, exerting pressure and causing the rock to break apart
Plant Roots
These organisms produce acids that chemically weather the rock surface.
Lichens and Mosses
Burrowing animals and insects can physically break down rocks
Animal Activities
Importance of Weathering
Soil Formation
Landscape Shaping
Nutrient Cycling