Chapter 6 Terms

Front 1

WEATHERING

Back 1

physical/mechanical breakdown (disintegration) and chemical alteration (decomposition) of rock at Earth’s surface

Front 2

Erosion

Back 2

physical removal of material by mobile agents: e.g. water, wind, ice, gravity. Exposes fresh unaltered rock to weathering.

Front 3

Physical weathering

Back 3

is the physical removal of material by wind, water, gravity, etc.

Front 4

Chemical weathering

Back 4

is the chemical alteration of a material that dissolves or degrades that material

Front 5

Frost wedging

Back 5

water freezing within cracks expands

freeze-thaw

Front 6

root wedging

Back 6

when roots pop up out of the ground and remove rock

Front 7

Salt Wedging

Back 7

evaporation of water rich in dissolved species will lead to growth of crystals in cracks
- exerts force.

Calcite (CaCO3), Gypsum (CaSO4), Halite (NaCl).

Front 8

Thermal Expansion

Back 8

large daily temperature changes
cause thermal strain (expansion & contraction).

Front 9

unloading

Back 9

uplift& erosion reduces pressure

Front 10

Exfoliation

Back 10

is the term used to describe rocks that are flaking apart in large sheets

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Dissolution

Back 11

promoted by acid water

Front 12

Hydrolysis

Back 12

reaction of mineral with water.

Hydrogen ion attacks and replaces other ions.

Front 13

Oxidation

Back 13

Loss of an electron via chemical reaction (often due to exposure to oxygen)

Front 14

LEO

Back 14

Lose an Electron = Oxidation

Front 15

GER

Back 15

Gain an Electron = Reduction

Front 16

Iron released from ferromagnesian silicates:

Back 16

e.g. olivine, pyroxene, amphibole, biotite mica.

Front 17

Regolith

Back 17

Layer of weathering products at the Earth’s surface:
rock and mineral fragments.

Front 18

Soil

Back 18

Combination of mineral and organic matter plus water and air.
The portion of the regolith that can support the growth of plants.

Front 19

Humus

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Decayed remains of animal and plant life (organic matter)
- essential part of soil.

Front 20

Residual soil

Back 20

developed on bedrock.

Front 21

Transported soil:

Back 21

on unconsolidated deposits

Front 22

Factors Controlling Soil Formation

Climate

Back 22

Most influential control.
Key factors are temperature and precipitation.

Front 23

Factors Controlling Soil Formation

Time

Back 23

Amount of time for soil formation varies for different soils depending on geologic and climatic conditions.

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Factors Controlling Soil Formation

Plants and animals:

Back 24

Influence soil physical & chemical properties. Microorganisms, worms.

Front 25

Factors Controlling Soil Formation

Topography:

Back 25

steep vs. gentle slopes.

Front 26

Topsoil

Back 26

rich in humus much biological activity

Front 27

Bedrock

Back 27

unweathered parent rock