| A | B |
|---|
| weathering | process that breaks down rocks into smaller pieces |
| mechanical weathering | breaks apart rocks without changing chemical composition |
| ice wedging | the cycle of freezing and melting that breaks rocks apart |
| chemical weathering | occurs when water, air, or other substances react with minerals in rocks |
| oxidation | occurs when a substance is exposed to oxygen and water |
| climate | pattern of weather in a particular area over a period of time |
| soil | mixture of weathered rock, decaying organic matter, mineral fragments, water and air |
| humus | organic matter found in soil |
| soil profile | vertical section of soil layers |
| horizon | a soil layer |
| leaching | occurs when soil materials dissolved in water are carried down through soil layers |
| desertification | the formation of a desert |
| horizon A | also known as topsoil, may be covered with litter |
| horizon B | less evolved layer, below Acontains material moved down by leaching |
| horizon C | bottom layer of soil, contains materials leached from B |
| litter | consists of leaves, twigs and other organic material |
| carbonic acid | weak acid that reacts with limestone, may form caves |
