Mechanical (Physical) Weathering

Mechanical (Physical) Weathering

What causes it?

What happens?

What do the effects look like?

What causes it?

What happens?

What do the effects look like?

What is Mechanical Weathering?What is Mechanical Weathering? Mechanical Weathering is… …the physical breaking down of rock is

into smaller pieces.

Mechanical Weathering is… …the physical breaking down of rock is

into smaller pieces.

What can cause mechanical weathering?What can cause mechanical weathering? Pressure release Ice wedging/ freezing & thawing Animals burrowing Plant roots Abrasion by wind or water

Pressure release Ice wedging/ freezing & thawing Animals burrowing Plant roots Abrasion by wind or water

Mechanical weathering by release of pressureMechanical weathering by release of pressure

This is an example of exfoliation This is an example of exfoliation

Exfoliation is a kind of mechanical weathering that happens the pressure or stress on the rock is reduced (usually by the erosion of whatever was on top)

Exfoliation is a kind of mechanical weathering that happens the pressure or stress on the rock is reduced (usually by the erosion of whatever was on top)

Another example of exfoliation:Another example of exfoliation: Look for this kind of weathering in the core of mountain chains

like the Appalachians -

Look for this kind of weathering

in New Hampshire

Look for this kind of weathering in the core of mountain chains like the Appalachians -

Look for this kind of weathering

in New Hampshire

The OnionThe Onion

This shows a kind of exfoliation too This shows a kind of exfoliation too

Another onion…Another onion…

… the release of pressure on the outside of the rock allows the outer layers to spall

… the release of pressure on the outside of the rock allows the outer layers to spall

Mechanical weathering can be caused by plantsMechanical weathering can be caused by plants In this picture, the tree growth has enlarged the crack in the rock In this picture, the tree growth has enlarged the crack in the rock

Mechanical weathering by plantsMechanical weathering by plants Roots growing in the cracks in the rock force it apart Roots growing in the cracks in the rock force it apart

Mechanical Weathering by PlantsMechanical Weathering by PlantsThe growth of tree roots forces rocks apartThe growth of tree roots forces rocks apart

Mechanical Weathering by PlantsMechanical Weathering by PlantsRoot wedgingRoot wedging

Mechanical Weathering by IceMechanical Weathering by IceIce forces rock apart because it expands as it freezesIce forces rock apart because it expands as it freezes

Mechanical Weathering by IceMechanical Weathering by Ice Example of an environment in which weathering by ice occurs: Example of an environment in which weathering by ice occurs:

Mechanical Weathering by Wind AbrasionMechanical Weathering by Wind Abrasion The wind carries sand, and acts like sandpaper! The wind carries sand, and acts like sandpaper!

Mechanical Weathering by Wind AbrasionMechanical Weathering by Wind AbrasionWind abrasion has produced gorgeous landscapes on the

Colorado Plateau west of the Rockies!Wind abrasion has produced gorgeous landscapes on the

Colorado Plateau west of the Rockies!

Mechanical Weathering by Water AbrasionMechanical Weathering by Water Abrasion Sediment carried by water can scour rock like sandpaper! Sediment carried by water can scour rock like sandpaper!

Mechanical Weathering by Water AbrasionMechanical Weathering by Water Abrasion These beach rocks are scoured and polished by wave action: These beach rocks are scoured and polished by wave action:

Mechanical Weathering: ReviewMechanical Weathering: Review Rocks physically broken into smaller pieces:

Pressure release (exfoliation, spalling)

Rocks physically broken into smaller pieces: Pressure release (exfoliation, spalling)

Mechanical Weathering: ReviewMechanical Weathering: Review Plants and Animals: Plants and Animals:

Mechanical Weathering: ReviewMechanical Weathering: Review Ice Wedging and Freeze/ Thaw Ice Wedging and Freeze/ Thaw

Mechanical Weathering: ReviewMechanical Weathering: Review Abrasion by:

Wind

Water

Abrasion by: Wind

Water