Rocks And Weathering

Front 1

Weathering

Back 1

Disintegration of rocks and minerals in situ without affecting its chemical composition

Front 2

Mechanical weathering

Back 2

Physical disintegration of rocks without affecting their components.

Front 3

Chemical Weathering

Back 3

Decomposition of rocks in situ

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The Peltier diagram

Back 4

-Illustrates the relationship between the amount of regolith depositied with the rainfall and temperature of a climate.

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Block disintegration

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Splitting of rocks along joints

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Granular disintegration

Back 6

When individual grains of sand are broken off (normally through salt crystalization)

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Bilogical Weathering

Back 7

Disintegration of rock due to action of plants + animals
i.e. roots grow into crevices, widen them instigating block disintegration

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Chelation

Back 8

When humic acid (composed by decomposed vegetation) are released and these acids attack clay/other minerals - releasing iron + aluminium

Front 9

Oxidation (rusting)

Back 9

When iron reacts with oxygen to produce reddish-brown coating (rust)

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Carbonation

Back 10

Form of chemical weathering
- occuring in rocks with calcium carbonate (chalk, limestone, rainfall combined with carbon dioxide/organic acid forming weak carbonic acid. Calcium carbonate reacts with acidic water forming calcium bicarbonate (soluble)

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Hydrolosis

Back 11

Form of chemical weathering:
- occuring in granite - reacts with acidic water forming kaolin (china clay), silicic acid, potassium hydroxyl - kaolin left. as the other 2 are removed in solution

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Hydration

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Chemical weathering-
-Certain minerals absorb water, expand and change
i.e. gypsum changing to anhydrate

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Frost shattering
or Freeze thaw

Back 13

Water freezes in rocks and expands- causing rock crevices to widen
(common in areas of fluctuation temperatures)

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Exfoliation/Onion-skin layering

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The expansion and contraction of rock Outer layer heats and cools more rapidly = causing stress and the outer layer to peel off.

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Spheroidal Weathering

Back 15

A form of chemical weathering

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Spheroidal Weathering

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A form of chemical weathering:
creates rounded boulders - creates domed monoliths*; whenever a rock experienced a massive drop in pressure and ambient heat (mostly in
granites)

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Dilatation

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Material stretched beyond normal means
(physical weathering)

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Sheer Stress

Back 18

Stress applied tangentialy to the surface of the rock

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Mass Movement

Back 19

The detachment and downslope movement of weathered + unweathered material (rock, regolith etc)

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Slope Creep

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Imperceptibly slow downslope movement of regolith (normally occuring in regions of high vegetation density)

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Solifluction

Back 21

Slow viscuous downslope movement of waterlogged regolith

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Fall

Back 22

Detached blocks of bedrock topple from a cliff face or steep slope. (where mechanical weathering is active on exposed rock surfaces and joint systems)

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Avalanche

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Rockfall material pulverised by impatc at cliff/slope foot and continues to travel downslope- at great speed.Velocity is sustained by a cushion of air trapped beneath the mass.

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Slide

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Rock slide:
Blocks become detached from underlying rocks and side over
Debris slide:
The slithing of weathered regolith debris over bedrock

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Slump

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Slope failure when 1 or more slope segments slip with a downward and outward Rotational slip along a concave-up slip surface
(common where stronger rocks overlie weaker, deformable beds)

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Flow

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Downslope movement of regolith containing much water; materials flow as viscuous flurry.
Debris flows: more coarse materials
Mudl flows: finer material