Chapter 6 test 2

Question 1

weathering

Answer 1

external process
physical breakdown and chemical alteration of rock at or near the earths surface.
mechanical and chemical

Question 2

mass wasting

Answer 2

external process

transfer of rock and soil downslope under the influence of gravity(landslides)

Question 3

Erosion

Answer 3

external process

the physical removal of material by mobile agents such as water, wind, ice or gravity

Question 4

mechanical weathering

Answer 4

breaking of rocks into smaller pieces

frost wedging, sheeting, salt crystal growth, biological activity

Question 5

frost wedging

Answer 5

alternate freezing and thawing of water in fractures and cracks promotes the disintegration of rocks.

Question 6

sheeting

Answer 6

exfoliation of igneous and metamorphic rocks at the earths surface due to a reduction in confining pressure. when overlying layers are eroded away, the outer layers expand and separate from the rock body. ex: joints

Question 7

Joints

Answer 7

fractures in the rock caused by expansion or rock, contraction of rock or cracking of rocks by mountain building forces.

Question 8

salt crystal growth

Answer 8

similar to frost wedging but instead of freeing water, salt crystals get inside and grow. occurs at seashores with a lot of sea spray.

Question 9

biological activity

Answer 9

disintegration resulting from plants and animals

Question 10

chemical weathering

Answer 10

breaks down rock components an the internal structure of minerals. water is usually involved
oxidation, dissolution, hydrolysis, spheroidal weathering

Question 11

oxidation

Answer 11

oxygen dissolved in water will cause oxidation which weakens materials with iron in them.

Question 12

dissolution

Answer 12

process by which carbonic acid in the water dissolves rocks such as limestone

Question 13

hydrolysis

Answer 13

carbonic acid reacts with feldspar and breaks it down to produce clay

Question 14

spheroidal weathering

Answer 14

causes physical changes by rounding corners.

forms when angular rock is chemically weathered as water enters joints

Question 15

differential weathering

Answer 15

rocks do not weather uniformly due to regional and local factors. an important factor is rock composition.

Question 16

regolith

Answer 16

rock and mineral fragments produced by weathering

Question 17

soil

Answer 17

a combination of mineral and organic matter, water, and air.
50% is made of disintegrated rock and minerals plus Humus
50% is made of pore spaces between solid particles where nutrient water and air cirulate

Question 18

factors controlling soil formation

Answer 18

parent material
time
climate
plants and animals
slope

Question 19

parent material

Answer 19

residue soil, parent material is the underlaying bedrock

transport soil, forms in a place on parent material that has been carried from elsewhere and deposited

Question 20

Time

Answer 20

amount of time for soil formation varies for different soils depending on geological and climate conditions.
it can take 80-400 years for .5in of soil

Question 21

climate

Answer 21

most influential control of soil formation

key factors are temperature and percipitaion

Question 22

plants and animals

Answer 22

organisms influence the soils physical and chemical properties.
also furnish organic matter to the soil

Question 23

slope

Answer 23

steep slopes often have poorly developed soils

Question 24

soil profile

Answer 24

soil forming processes operate from the surface downward.
vertical differences are called horizons- zones or layers of soil
-O horizon, A Horizon, E Horizon, B Horizon, C Horizon

Question 25

O Horizon

Answer 25

organic matter

O and A make up topsoil

Question 26

A Horizon

Answer 26

Humus and mineral matter
high biological activity
together the O and A horizons make up topsoil

Question 27

E Horizon

Answer 27

Little organic matter

zone of eluviation and leaching

Question 28

B Horizon

Answer 28

zone of acumulation

Question 29

C Horizon

Answer 29

partial altered parent material

Question 30

Laterite

Answer 30

a tropical soil that hardens to brick when vegetation is stripped away and sun backs the surface

Question 31

Paleosoil

Answer 31

an ancient soil that is buried. it can provide clues to past climates and landscapes

Question 32

bauxite

Answer 32

the worlds largest source of aluminum

concentrated in fragile tropical s oils