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Weathering, Soil, and WastingUnit 7 notesWeatheringWhat is it?Disintegration and Decomposition of rocks Where does it happen?At or near the surface of the Earth

WeatheringWhat does this process look like?

WeatheringWhy does it happen?It is the response of Earths materials to the changing environment.

WeatheringHow many types are there?MechanicalChemical

Weathering- MechanicalA physical processRocks are broken into smaller and smaller pieces, each retaining the characteristics of the original (parent) material

Weathering- MechanicalFrost WedgingWater enters and fills cracks in the rock. It will expand when the water freezes and push the rock apart more.

Weathering- MechanicalTalus SlopesThe pile of rocks that forms at the base of a vertical rock formation. Most often the result of frost wedging.

Weathering- MechanicalUnloadingLarge scale loss of rocks off of the original parent material

Weathering- MechanicalSheeting is also known as exfoliation. What is exfoliation on people?

Weathering- MechanicalSheeting-When large masses of rock (particularly igneous) are exposed and large flat pieces are broken off due to a reduction in pressure

Weathering- MechanicalThermal ExpansionWhat happens when you heat something up?Cool something down?

Weathering- MechanicalBiological activityPlants, animals (including humans), lichens, mossesPlant 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

Weathering- ChemicalCarbonic Acid-H2CO3 is produced when CO2 dissolves in H2O. Water vapor in the air undergoes this reaction.

Weathering- ChemicalHow carbonic acid works on Feldspar2 KAlSi3O8 + 2 H2CO3 + H20 Al2Si2O5(OH)4 + 2KHCO3 + 4SiO2

What it looks like

Weathering- ChemicalRocks that undergo this process tend to take on a spherical shape.

SoilScience, 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 1993SoilRegolithThe surface layer of the Earth that is composed only of weathered rock and mineral fragments

SoilWhat is it?A combination of weathered mineral particles, organic matter, water, and airWhat makes for good soil?A mixture of approximately 50% regolith and 50% humus (decayed organic material)

SoilThis is where erosion fits into the mix.

SoilAs materials are eroded, certain minerals and elements can be left behind or concentrated to form ore and mineral deposits.

Mass WastingLarge movements of rock and/or soil in a downhill direction

Mass WastingTriggers of mass wastingWater saturation

Mass WastingTriggers of mass wastingOversteepened slopes

Mass WastingTriggers of mass wastingVegetation- or rather removal of vegetation

Mass WastingTriggers of mass wastingEarthquakes