Weathering and soil

Question 1

Weathering occurs when the lithosphere (rocks) interacts with what 3 things

Answer 1

1. the atmosphere (gases),
2. the hydrosphere (water) and
3. The biosphere (organisms)

Question 2

Mechanical Weathering occurs when mechanical processes break large rocks into smaller fragments.

Answer 2

Frost Wedging – freezing and thawing of water in pores and fractures.
Sheeting (Exfoliation) – expansion producing rock sheets parallel to surface.
Biological Activity (Tree Roots) – growing roots wedge apart existing craacks in rocks.

Question 3

what is frost wedging

Answer 3

freezing and thawing of water in pores and fractures

Question 4

what is sheeting

Answer 4

expansion producing rock sheets parallel to surface

Question 5

what is biological activity

Answer 5

growing roots wedge apart existing cracks in rocks.

Question 6

Chemical Weathering involves? definition and then 3 types and their def

Answer 6

1. reactions among minerals and water and atmospheric gases.
2. Dissolution – reactions break apart molecules, which then disperse in water.
3. Hydrolysis – reactions consume mineral and water molecules, reorganizing them into new minerals and dissolved ions.
4. Oxidation – reactions with oxygen to form new substances by exchanging electrons.

Question 7

Clastic Sediment? what are the two types and their def?

Answer 7

Rock fragments and minerals – remaining from physical weathering.
Newly formed mineral grains – produced by chemical weathering.

Question 8

Chemical sediment?

Answer 8

Minerals precipitated from water – the ions composing these minerals are generated mostly by chemical weathering reactions.

Question 9

Several factors influence the type and rate of rock weathering. what 2 types are there and their def’s?

Answer 9

1. Rock characteristics – such as mineral composition/solubility and joints/cracks.
2. Climate – factors such as temperature and moisture..

Question 10

Major soil components 4 types and their def’s?

Answer 10

1. Inorganic materials – rock fragments and minerals that will not readily dissolve in water.
2. Soil water – original source is precipitation.
3. Soil air – voids not filled with water contain air or certain gases.
4. Organic matter – the decayed remains of plants and animals, collectively called humus.

Question 11

Soil profile?

Answer 11

the vertical cross section of a soil from the surface down to the parent material.

Question 12

Soil horizons?

Answer 12

occur in the soil profiles of well-developed soils that exhibit distinct layers that are distinguished by their physical and chemical properties.

Question 13

Soil scientists have observed that soil development is a function of five soil-forming factors. what are their names and def’s?

Answer 13

1. Parent material – weathered mineral matter (residual or transported) from which soil is formed.
2. Organisms– activity of plants, animals and micro-organisms.
3. Climate – effect of temperature and precipitation is very important to soil formation.
4. Topography (relief) – the slope of the landscape is an important influence on soil formation.
5. Time – soils develop toward a state of equilibrium (maturity) with their environment.