| A | B |
|---|
| weathering | the process by which natural forces break down rocks |
| mechanical weathering | the breakdown of rock into smaller pieces of the same material without any change in its composition |
| exfoliation | the process in which layers or sheets of rock gradually break off |
| abrasion | the process of wearing down rock by friction |
| chemical weathering | the breakdown of rock by chemical reactions that change the rock's composition |
| humus | the decayed organic matter in soil |
| soil horizon | a soil layer with physical and chemical properties that differ from those of soil layers above or below it |
| soil profile | the soil horizons in a specific location;a cross section of soil layers that displays all soil horizons |
| desertification | the expansion of desert conditions in areas where the natural plant cover has been destroyed |
| erosion | the process in which weathered particles are picked up and moved from one place to another |
| deposition | the part of the erosion process in which sediment travels to a new location |
| mass wasting | the downhill movement of a large amount of rock or soil |
| drainage basin | an area of land in which water drains into a stream system |
| divide | a ridge from which water drains to one side or the other |
| floodplain | a flat area of land on either side of a stream that is underwater when the stream floods |
| alluvial fan | a fan shaped deposit of sediment at the base of a mountian |
| delta | an area of land at the end, or mouth, of a river that is formed by the buildup of sediment |
| sinkhole | an open basin that forms when the roof of a cave becomes so thin that it falls in |
| sandbar | a ridge of sand built up by the action of waves and currents |
| barrier island | a long, narrow island that develops parallel to a coast |
| loess | deposits of fine-grained,wind blown sediment |
| glacier | a large mass of ice that moves over land |
| till | sediment left directly on the ground by a retreating, glacier |
| moraine | the buildup of till left behind by a retreating glacier |
| kettle lake | a bowl-shaped lake that was formed as sediment built up around a block of ice left by a glacier |
