WEATHERING: breakup of rock due to exposure to processes that occur at or near Earth’s surface

TWO TYPES:1. Mechanical (physically)2. Chemical (chemically)

Ice Wedging

MECHANICAL WEATHERING: Ice Wedging: ice freezes and expands w/in cracks and breaks apart rock

Abrasion: scraping

Exfoliation: peeling of surface layers

Root Wedging: roots push apart cracks in rocks

Abrasion

Exfoliation

Weathering by Living Things (Biomechanical/Physical)

Hydrolysis: chemical reaction of rock with water

Oxidation: exposure of rock to oxygen causes chemical reactions

Root Leaching: plants use minerals in rock as nutrients which cracks rocks

Carbonic Acid: acid rain (water + CO2)

CHEMICAL WEATHERING

Karst Topography- Caves!

Oxidation Oxidation of Desert Landscape

Root Leaching

Acid Rain- corrodes marble & limestone!

Karst Topography• Chemical weathering of limestone

& dolomite bedrock due to acid rain (hydrolysis)

• Lots of salt and gypsum minerals- highly soluble in water

• Forms caves and different landforms

Karst Landforms

Rates of Weathering Depend on…

1. Surface area exposure- the more surface area exposed, the faster the rate of weathering

2. Composition of rock- some minerals are weathered easier than others

3. Climates1. Warm, wet climates are conducive to BOTH

chemical and mechanical2. Cold, dry climates mechanical weathering

plays a greater role than chemical- ice, wind, snow/glacier movement

EROSION:transportation and movement of weathered sediments AGENTS:1. wind 4. gravity2. water 5. volcanoes3. glaciers

Wind

Water

Ice

Gravity

Volcanic Eruption

MASS WASTING

Talus – rock fragments that have been weathered from a cliff and pulled down by gravity

Types of Mass Wasting

1. landslide2. mudslides & mudflows3. creep4. slump

Creep

Slump

Mudflow

Earth flow• Landslide NatGeo• Man Catches Land

slide on Tape• Landslide in CA