Unit 7 notes Weathering What is it Disintegration and Decomposition of rocks Where does it happen At or near the surface of the Earth Weathering What does this process look like Weathering ID: 802875
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Slide1
Weathering, Soil, and Wasting
Unit 7 notes
Slide2Weathering
What is it?
Disintegration and Decomposition of rocks
Where does it happen?At or near the surface of the Earth
Slide3Weathering
What does this process look like?
Slide4Weathering
Why does it happen?
It is the response of Earth’s materials to the changing environment.
Slide5Weathering
How many types are there?
Mechanical
Chemical
Slide6Weathering- Mechanical
A physical process
Rocks are broken into smaller and smaller pieces, each retaining the characteristics of the original (parent) material
Slide7Weathering- Mechanical
Frost Wedging
Water enters and fills cracks in the rock. It will expand when the water freezes and push the rock apart more.
Slide8Weathering- Mechanical
Talus Slopes
The pile of rocks that forms at the base of a vertical rock formation. Most often the result of frost wedging.
Slide9Weathering- Mechanical
Unloading
Large scale loss of rocks off of the original parent material
Slide10Weathering- Mechanical
Sheeting is also known as exfoliation.
What is exfoliation on people?
Slide11Weathering- Mechanical
Sheeting-
When large masses of rock (particularly igneous) are exposed and large flat pieces are broken off due to a reduction in pressure
Slide12Weathering- Mechanical
Thermal Expansion
What happens when you heat something up?
Cool something down?
Slide13Weathering- Mechanical
Biological activity
Plants, animals (including humans), lichens, mosses
Plant roots will wedge in between rocks to seek water. Lichens will actually digest the surface of rocks for nutrients. And humans will do what we do…
Slide14Weathering- Chemical
Carbonic Acid-
H
2CO3 is produced when CO
2
dissolves in H
2
O.
Water vapor in the air undergoes this reaction.
Slide15Weathering- Chemical
How carbonic acid works on Feldspar…
2 KAlSi
3O8 + 2 H
2
CO
3
+ H
2
0
Al
2
Si
2
O
5
(OH)
4
+ 2KHCO
3
+ 4SiO
2
What it looks like…
Slide16Weathering- Chemical
Rocks that undergo this process tend to take on a spherical shape.
Slide17Soil
“Science, in recent years , has focused more and more on the Earth as a planet, one that for all we know is unique-where a thin blanket of air, a thinner film of water and the thinnest veneer of soil combine to support a web of life of wondrous diversity in continuous change.”
Jack Eddy 1993
Slide18Soil
Regolith
The surface layer of the Earth that is composed only of weathered rock and mineral fragments
Slide19Soil
What is it?
A combination of weathered mineral particles, organic matter, water, and air
What makes for good soil?A mixture of approximately 50% regolith and 50% humus (decayed organic material)
Slide20Soil
This is where erosion fits into the mix.
Slide21Soil
As materials are eroded, certain minerals and elements can be left behind or concentrated to form ore and mineral deposits.
Slide22Mass Wasting
Large movements of rock and/or soil in a downhill direction
Slide23Mass Wasting
Triggers of mass wasting
Water saturation
Slide24Mass Wasting
Triggers of mass wasting
Oversteepened
slopes
Slide25Mass Wasting
Triggers of mass wasting
Vegetation- or rather removal of vegetation
Slide26Mass Wasting
Triggers of mass wasting
Earthquakes