Mechanical WeatheringMechanical Weathering

MackenzieMackenzieKevinKevinMattMattSamSam

MarissaMarissaVeronicaVeronica

Mechanical WeatheringMechanical Weathering

• Mechanical weathering includes several processes that break rock into smaller pieces. (physical disintegration)

TypesTypes

• Mechanical weathering is broken down into two main categories frost action and pressure release

Frost WedgingFrost Wedging• The expansion of freezing water in rock

cracks which push the rock further apart

• Water in cracks can expand as much as 9%

• Leads to further cracking or parts of the rock splitting off

Frost HeavingFrost Heaving

• Lifts rock and soil upwards

• Ice forms under boulders and expands which pushes them upwards

• Causes cracks in roads during winter time

Pressure ReleasePressure Release

• Tectonic uplift causes rocks to near the surface of the earth crust

• As they near a pressure change occurs due to the removal of weight (other rocks on top)

• The removal of weight allows for the granite to expand upwards

Sheet JointsSheet Joints• Formed be pressure release

• Outer part of the rock expands more then the inner part

• These “sheets” of rock can break off due to gravity forming concentric slabs, this is known as exfoliation

Biological ActivityBiological Activity

• Plant growth such as growing roots can lead to the cracking of rocks

• Burrowing animals can also have an effect on rocks

Salt Crystals ( Haloclasty)Salt Crystals ( Haloclasty)• As water

evaporates in small cracks of rocks salt crystals can form

• These salt crystals exert pressure due to their expanded form, helps disintegrate

• Occurs in desert climates

AbrasionAbrasion• The process of breaking and chipping

away at rocks caused by the impact of other matter (grinding together, smashing etc)

ErosionErosion

• Erosion is caused by wind, rain and other processes or things which breaks down the surface of the Earth or rocks.

Pressure Release

Frost Heaving

Frost Wedging

Exfoliation

Sheet Joints

Erosion

Haloclasty

Abrasion

-Uplift of rocks caused by ice

-Splitting apart of rock by ice-Can break off due to gravity-The breaking of rocks

caused by impact of other object

-Process of spalling off rock layers

-The expansion of rocks due to the removal of weight on top

-Disintegration of rock (occurs in desert climates)

- The process of breaking things down