Rates of Weathering

Lubov McKoneLauren BrooksbyAndrew Beebe

Stephanie Zuritis

The Rate of Weathering

• The rate of weathering is the speed at which rock or soil is broken down.

Grand Canyon- 5-6 million years of

weathering

Niagra Falls- 12,000 years of weathering

Zion Canyon- 200 million years of

wind erosion

Rock Composition• The more soluble the minerals are that

compose the rock the faster the rock will weather.

LimestoneGranite

MicaRock Salt

Topography

Topography affects the rate of weathering because if you have rough

steep slopes, there is more area expose to rain, wind… Therefore, because of what we have learned from surface

area, we know that steeper slopes with weather faster than a flat area.

Other Things That Affect The Rate Of Weathering

• Plants and animals can affect the rate of weathering because if you are in a place where there are lots of plants and animals, they will be

walking, digging, burrowing and doing many things that would make rocks weather. So if you are in an area with more animals and plants, the

rocks may weather faster.

Amount of Exposure

(surface area) When a rock is broken into smaller pieces, usually through mechanical weathering, the surface area of the rock is increased, creating more surfaces to weather. This will increase the rate of weathering of the rock.

For example,

these broken up

halite crystals will

weather much faster

than this full halite

crystal.

Climate Rocks weather fastest in a hot,

wet, climate

This hot, arid climate has more weathering that is caused by wind (slower)….

Whereas weathering in this wetter climate depends more on water (faster)

Rock Composition

The Rock Salt composition is halite which can dissolve in water more easily.

Limestone is composed of calcite which will dissolve slower in water than the Rock Salt.

Surface Area

As a rock is broken up into more pieces the surface area of the rock increases. Which then lets mechanical and chemical weather more sides.