| A | B |
|---|
| weathering | process that decomposes rock and convert them to loose gravel, sand, clay and soil are called |
| erosion | carry off weathered rock and minerals |
| common types of erosion | rain, running water, wind, glaciers, and gravity |
| Mechanical weathering | also called physical weathering reduces soild rock to small fragments but does not alter the chemical composition |
| chemical weathering | when air and water chemically react with rock to alter its compsition and mineral content |
| five different processes that cause mechanical weathering | Pressure-release fracturing, frost wedging, abrasion, organic activity, thermal expansion and contraction |
| frost wedging | water expands when freezes, water accumulates in a crack and then freezes its expansion pushes the rock apart |
| abrasion | rocks, grains of sand, and silt collide |
| thermal expansion and contraction | when rock heats or cools faster than its interior, the surface expands or contracts faster then the interrior |
| rusting | ex of oxidation |
| salt cracking | growing crystals exert tremendous forces, enough to loosen mineral grains and widen cracks |
| exfoliation | process in which larger plates or shells split away like layers of an onion (ex. granite ) |
| soil | also called regolith |
| humus | litter decomposes sufficiently that you can no longer determine the origin of individual pieces |
| soil horizions | O A B C bedrock |
| O horizion | mostly organic matter |
| A horizion | topsoil - high concentration of organic matter |
| B horizion | subsoil - clay and cations leached from A horizon |
| C horizion | weathered rock |
| Debris flow | more than half particles larger than sand size |
| earthflow and mudflow | movement of fine grain - large amouns of water |
| rockslide | newly detached segment of bedrock |
| slide | tress on slump blocks remain rooted |
