Earth/Environmental Science Essential Vocabulary
Chapter 5
1. Mechanical weathering- the physical disintegration of rock, resulting in
smaller fragments
2. Frost wedging- the mechanical breakup of rock caused by the expansion of
freezing water in cracks and crevices
3. Talus- an accumulation of rock debris at the base of a cliff
4. Exfoliation- type of weathering caused by reducing pressure on a rock
surface, allowing slabs of outer rock to break off in layers
5. Chemical weathering- the processes by which the internal structure of a
mineral is altered by the removal and/or addition of elements
6. Regolith- the layer of rock and mineral fragments that nearly everywhere
covers Earth’s surface
7. Soil- a combination of mineral and organic matter, water, and air; that portion of
the regolith that supports plant growth
8. Soil Horizon- a layer of soil that has identifiable characteristics produced by
chemical weathering and other soil-forming processes
9. Soil Profile- a vertical section through a soil showing its succession of
horizons and the underlying parent material
10. Pedalfer- soil of humid regions characterized by the accumulation of iron
oxides and aluminum-rich clays in the B horizon
11. Pedocal- soil associated with drier regions and characterized by an
accumulation of calcium carbonate in the upper horizons
12. Laterite- a red, highly leached soil type found in the tropics that is rich in
oxides of iron and aluminum
13. Mass Movement- the downslope movement of rock, regolith, and soil
under the direct influence of gravity
14. Rockfall- occurs when rocks or rock fragments fall freely through the air
15. Rockslide- occurs when a mass of rock slides rapidly downslope along
planes of weakness
16. Slump- the downward slipping of a mass of rock or unconsolidated material
moving as a unit along a curved surface
17. Mudflow- quickly moving downhill flow of soil and rock fragments containing
a large amount of water
18. Earthflow- slow-moving downslope movement of water-saturated, clay-rich
sediment, most characteristic of humid regions
19. Creep- the slow downhill movement of soil and regolith