Chapter 6 Weathering And Soil

Front 1

chemical weathering, p 185

Back 1

a process changing a mineral's internal structure by removing elements, or adding elements, or both.

Front 2

differential weathering, p 196

Back 2

variations in both the rate and degree of weathering. Differential weathering is affected by mineral makeup, degree of jointing (cracking), and climate.

Front 3

dissolution, p 187

Back 3

a form of chemical weathering. Dissolution is the process of dissolving into a homogeneous solution. Dissolution goes on when acid dissolves limestone.

Front 4

eluviation

Back 4

a process by which material dissolved or suspended in water within soil moves down or sideways as rainwater moves through the soil

Hint 4

comment: eluvium is residual deposits of soil, dust, and rock particles produced by the action of the wind. But the root of the word comes from water . . ."eluere", to wash out

Front 5

erosion, p 185

Back 5

the transportation of materials by a moving agent such as water, ice, or wind

Front 6

exfoliation dome, p 186

Back 6

large, dome-shaped structure, usually composed of granite, formed by sheeting

Front 7

external processes, p 184

Back 7

weathering, mass wasting, or erosion powered by solar energy or gravity. These processes change solid rock into organic-free sediment (regolith).

Front 8

frost wedging, p 186

Back 8

the mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices.

Front 9

horizon, p 201

Back 9

a layer in a soil profile

Front 10

humus, p 197

Back 10

Organic matter in soil produced by the decomposition of plants and animals

Front 11

hydrolysis, p 190

Back 11

A chemical weathering process where minerals on a rock's surface are altered by reactng with molecules derived from the splittng apart of water. The water breaks up into hydrogen ions (paired hydrogen atoms) and hydroxyl ions (a molecule made of paired oxygen and hydrogen).

Front 12

internal process, p 185

Back 12

A process such as mountain building or volcanism that derives its energy from the earth's interior. Internal processes elevate the Earth's surface.

Front 13

leaching, p 203

Back 13

the depletion of soluble materials from the upper soil by downard percolating water.

Hint 13

leaching is eluviation of dissolved materials by water. The water is usually a bit acidic.

Front 14

mass wasting, p 185

Back 14

gravity-caused movement of rock, regolith, and soil down a slope

Front 15

mechanical weathering, p 185

Back 15

the physical disintegration of rock resulting in small fragments (this dis NOT chemical breakdown)

Hint 15

physical disintegration can speed up chemical breakdown by making the pieces smaller and smaller and thus easier to dissolve

Front 16

oxidation, p 185

Back 16

the removal of one or more electrons from an atom in a compound. Oxidation got its name because many elements can combine with oxygen by losing an electron. When substances oxidize, they become less rigid and increasingly unstable chemically.

Hint 16

Common oxides are of iron and aluminum
red soil = iron oxide
yellow soil = aluminum oxide

Front 17

parent material, p 198

Back 17

the material underground from which a soil develops

Front 18

regolith, 197

Back 18

soil without any biological material (plants or animal remains). Regolith is everywhere where rocks break down. If it mixes with organic remains, regolith becomes soil.

Hint 18

The surface of the moon is covered with regolith, not with soil.

Front 19

sheeting, p 186

Back 19

a mechanical weathering process where slablike sheets or rock split off from the main rock mass.

Front 20

soil, p 197

Back 20

a combination of mineral and organic matter, water, and air. Soil is that part of the regolith that supports plant growth.

Front 21

soil profile, p 201

Back 21

a vertical section through a soil, showing its succession of horizons and the underlying parent material

Front 22

soil taxonomy, p 204

Back 22

a soil classification with six hierarchical categories based on soil characteristics. The system recognizes 12 soil orders.

Hint 22

OMIT - we're not going into this

Front 23

spheroidal weathering, p 194

Back 23

any weathering process producing spherical shape from an initially blocky shape

Front 24

talus slope, p 186

Back 24

the sloping accumulation of rock debris often piling up at the base of a cliff. see the diagram on page 702

Hint 24

talus can also be called "Scree"

Front 25

weathering, p 185

Back 25

either disintegration or decompostition (or both) of rock at or near the earth's surface

Front 26

top soil

Back 26

The uppermost two soil horizons where biological activity occurs. Top soil includes the O horizon where loose organic matter accumulates as humus together with the
A horizon which consists of both organic and mineral matter.

Front 27

subsoil

Back 27

The lower two horizone in a soil profile where mosts of the chemical activity occurs. Subsoil consists of the E horizon (the zone of eluviation and leaching)together with the
B horizon (zone where leached materials are deposited and accumulate.

Front 28

saprolite

Back 28

soft, partially decomposed rock at the base of a soil profile. Saprolite is rich in clay and remains in its original place. Much of Arlington, Virginia, is covered by saprolite.