Weathering and Erosion

WEATHERING

Process of rock disintegration into mineral due to stresses

Degree of weathering on rocks depends on: Minerals and stress

Influenced by various factors (Temperature & Climate)

Rule of thumb: Minerals formed under high temperature and resistant (Vice versa) pressure=less

Results to higher susceptibility to different forms of weathering

No transportation involved

Happens on specific location

Precedes erosion

EROSION

Process where the surface of the earth is worn away

Bits of rocks/soil are move from one place to another

Usually caused by agents of dispersal (wind, water, ice or gravity)

Happens at the top of the mountains

Can also happen under the soil

Can result to creation of wetlands at the mouth of rivers

Indicator: Muddy waters

SUMMARY

Weathering

a process of rock disintegration due to biological, chemical, and mechanical stresses.

Erosion

a process where portions of the Earth's surface such as soil and rocks particles are moved from one place to another

*The main difference between weathering and erosion is that there is involvement of material transport in weathering

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Describing how rocks undergo Weathering

Weathering

process where rocks are broken down into smaller pieces, worn away, or dissolved

caused by abiotic and biotic factors

Weathering Agents:

Water

Temperature Atmospheric

Biotic

Rate of weathering is affected by:

amount of exposed surface area

mineral composition of rock

prevailing climate

Types of Weathering

Chemical Weathering

Major Processes:

1. Dissolution

2. Hydrolysis

3. Oxidation

Mechanical or Physical Weathering

Major Processes:

1. Frost wedging

2. Exfoliation

3. Thermal expansion and contraction

Organic or Biological Weathering

Chemical Weathering

changes due to chemical activities

modifies rock composition

agents of chemical

weathering:

Oxygen

rainwater

carbon dioxide

acids

Products of chemical weathering:

Clays minerals = Ex. Chlorite

Metal ores = Ex. Iron

Oxide minerals = Ex. Manganese

Chemical Weathering: Major Processes

1. Dissolution

elements dissolve in water

Ex. Salt dissolving in water

2. Hydrolysis

positive ions are replaced by active hydrogen ions that comes with water

Ex. Salt dissolving in water

3. Oxidation

oxygen interacts with minerals

Ex. Rusting of iron metal

Mechanical or Physical Weathering

due to physical stresses

changes the physical attributes but composition stays the same

occurs due to changes in temperature and pressure

Mechanical or Physical Weathering: Major Processes

Frost wedging

Exfoliation

Thermal expansion and contraction

Frost Wedging Ex. Splitting of rocks

key agent is water

affected by changes in temperature

exerts force on the rack which leads to cracking and separation of particles

common in high altitude areas

Exfoliation Ex. Half dome

detachment of sheets of rocks due to instability in pressure

pressure inside the rock is greater than pressure on surface of the rock permitting expansion

Thermal Expansion and Contraction

Alternate expanding and contraction of crystals due to heating and cooling

Extreme and sudden change in temperature

Biological Weathering

plants, animals, and microorganisms as agents of rock disintegration

integration of mechanical and chemical weathering

plants growing on rocks

lichen and algae inhabiting rock surface

lichen releases organic acids the minerals are consumed by the algae

process increases susceptibility of rocks to mechanical and chemical weathering

Weathering is the process of rock disintegration into smaller mineral components due to various stresses, without involving transportation of materials.

Erosion is the process whereby the surface of the Earth is worn away and bits of rocks or soil are moved from one place to another, typically caused by agents such as wind, water, ice, or gravity.

Weathering is caused by various stresses, including biological, chemical, and mechanical factors, and is influenced by temperature, climate, mineral composition, and the amount of exposed surface area of rocks.

Yes, the causes of weathering are considered both biotic and abiotic, where biotic factors include the activities of plants, animals, and microorganisms, and abiotic factors encompass physical and chemical processes such as temperature changes, water, and atmospheric conditions.

The three types of weathering are chemical weathering, which alters rock composition through chemical reactions; mechanical (or physical) weathering, which breaks rocks into smaller pieces without changing their composition; and biological weathering, where living organisms contribute to the breakdown of rocks through physical or chemical means.

Weathering is the process that breaks down rocks and minerals into smaller pieces through various physical, chemical, and biological means without moving those particles, while erosion involves the transportation of these weathered materials from one location to another by agents such as wind, water, ice, or gravity, highlighting that weathering focuses on disintegration and alteration, whereas erosion emphasizes displacement and movement.