| A | B |
|---|
| Mechanical weathering | the physical disintegration of rock, resulting in smaller fragments |
| Frost wedging | the mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices |
| Talus | an accumulation of rock debris at the base of a cliff |
| Exfoliation | type of weathering caused by reducing pressure on a rock surface, allowing slabs of outer rock to break off in layers |
| Chemical weathering | the process by which the internal structure of a mineral is altered by the removal and/or addition of elements |
| Regolith | the layer of rock and mineral fragments that nearly everywhere covers EarthÕs surface |
| Soil | a combination of mineral and organic matter, water, and air; the portion of the regolith that supports plant grown |
| Soil profile | a vertical section through a soil showing its succession of horizons and the underlying parent material |
| Pedalfer | soil of humid regions characterized by the accumulation of iron oxides and aluminum rick clays in the B horizon |
| Pedocal | soil associated with drier regions and characterized by an accumulation of calcium carbonate in the upper horizons |
| Laterite | a red, highly leached soil type found in the tropics that is rich in oxides of iron and aluminum |
| Mass movement | the downslope movement of rock, regolith, and soil under the direct influence of gravity |
| Rockfall | occurs when rocks or rock fragments fall freely through the air; common on steep slopes |
| Rockslide | occurs when a mass of rock slides rapidly downslope along planes of weakness |
| Mudflow | quickly moving downhill flow of soil and rock fragments containing large amounts of water |
| Earthflow | slow-moving downslope movement of water-saturated, clay-rich sediment; most characteristic of humid regions |
| Creep | the slow downhill movement of soil and regolith |
