Geology Chapter 4

Soil

A combination of mineral and organic matter, water, and air; that portion of the regolith that supports plant growth.

Slide

A movement common to mass-wasting processes in which the material moving downslope remains fairly coherent and moves along a well-defined surface.

Weathering

The disintegration and decomposition of rock at or near Earth's surface.

Mass Wasting

The downslope movement of rock, regolith, and soil under the direct influence of gravity.

Slump

The downward slipping of a mass of rock or unconsolidated material moving as a unit along a curved surface.

Erosion

The incorporation and transportation of material by a mobile agent, such as water, wind, or ice.

Frost wedging

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

Mechanical Weathering

The physical disintegration of rock, resulting in smaller fragments.

Creep

The slow downhill movement of soil and regolith

Sheeting

a mechanical weathering process characterized by the splitting-off of slablike sheets of rock.

Debris Flow

a relatively rapid type of mass wasting that involves a flow of soil and regolith containing a large amount of water. Also called mudflows.

Flow

a type of movement common to mass-wasting processes in which water-saturated material moves downslope as a viscous fluid.

Fall

a type of movement common to mass-wasting processes that refers to the free falling of detached individual pieces of any size.

Talus

an accumulation of rock debris at the base of a cliff.

Exfoliation Dome

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

External processes

process such as weathering, mass wasting, or erosion that is powered by the Sun and transforms solid rock into sediment.

Earthflow

the downslope movement of water-saturated, clay-rich sediment. most characteristic of humid regions.

Regolith

the layer of rock and mineral fragments that nearly everywhere covers Earth's surface.

Parent Material

the material upon which a soil develops

Chemical Weathering

the processes by which the internal structure of a mineral is altered by the removal and/or addition of elements.

Rockslide

the rapid slide of a mass of rock downslope along planes of weakness.

Differential Weathering

the variation in the rate and degree of weathering caused by such factors as mineral makeup, degree of jointing, and climate.