Weathering and Soil

Question 1

Weathering

Answer 1

The process by which larger rocks get broken down into smaller pieces

Question 2

The means by which rocks can be weathered

Answer 2

physical means, chemical means, or both

Question 3

Erosion

Answer 3

The removal of weathered products

Question 4

Soil

Answer 4

A mixture of mineral and organic matter

Question 5

Soil horizons

Answer 5

The distribution of soil layers

Question 6

What are the Soil horizons

Answer 6

O Horizon
A Horizon
B Horizon
C Horizon
R Horizon

Question 7

O Horizon

Answer 7

The organic zone containing dead and decaying plant and animal remains; it’s normally dark in colour because of the large amount of humus

Question 8

Humus

Answer 8

Organic material (in the O Horizon)

Question 9

A Horizon

Answer 9

The surface layer of soil
Contains a mixture of organic material and mineral matter and is darker than the O Horizon

Question 10

The most productive and nutrient-rich portion of the soil horizon

Answer 10

The A horizon

Question 11

E horizon

Answer 11

A zone of leaching below the A horizon (only in some soils) where nutrients move out of it down toward the bedrock leaving behind iron; it’s generally lighter in colour

Question 12

B horizon

Answer 12

The “subsoil” or “zone of accumulation,” which consists of a variety of substances (organics, clay, small rocks)

Question 13

C horizon

Answer 13

The substratum
The parent material. Its composition is highly dependent on the type of bedrock below and usually contains fragments of the bedrock

Question 14

Loam

Answer 14

a soil that contains approximately equal amounts of clay, silt, and sand

Question 15

The desirable consistency of the A horizon

Answer 15

Loam

Question 16

The R horizon

Answer 16

Bedrock
The rock unit underlying the soil

Question 17

chemical weathering

Answer 17

when a rock disintegrates due to chemical reactions that happen within the environment

Question 18

The main process at work in caves

Answer 18

carbonic acid dissolving calcite in limestone

Question 19

The result of rocks rusting if iron is present

Answer 19

iron oxides like hematite or limonite

Question 20

mechanical weathering

Answer 20

the breakdown of rocks by physical or mechanical processes

Question 21

frost wedging

Answer 21

water gets into cracks in rocks, freezes, and expands, making the cracks in the rocks even bigger

Question 22

root wedging

Answer 22

roots from plants force open small fractures in rocks, which opens the door for other weathering processes

Question 23

pressure release/unloading

Answer 23

a type of mechanical weathering in which a rock
fractures because of expansion due to a heavy overlying pressure being removed.

Question 24

isostatic rebound

Answer 24

occurs when something heavy like glacial ice or large amounts of rock are removed from an area, the landscape underneath will respond by expanding upward (in pressure release mechanical weathering)

Question 25

Ways that moving water weathers rocks

Answer 25

abrasion hydraulic action cavitation

Question 26

Abrasion

Answer 26

Rocks smoothed by contact with sediment and other rocks

Question 27

Hydraulic action

Answer 27

the breaking apart of rocks by the sheer force of moving water

Question 28

cavitation

Answer 28

occurs when very fast moving water flows over small depressions in bedrock; small vacuum bubbles form and then implode, which damages the rock

Question 29

True or False: Wind is incredibly effective at weathering

Answer 29

False

Question 30

groundwater sapping

Answer 30

a process that occurs as groundwater pushes from the inside to the outside of a rock face.

Question 31

spheroidal weathering

Answer 31

when rocks (usually granites) become weathered into rounded shapes because at least two sets of perpendicular joints crisscross the granite

Question 32

differential weathering

Answer 32

when one rock type weathers faster than another.