| A | B |
|---|
| mechanical weathering | the breaking apart of rocks without changing their chemical composition |
| The difference between mechanical and chemical weathering | the way the effect the composition of the rock |
| causes of mechanical weathering | ice, tree roots, water |
| causes ice wedging | water freezing and thawing |
| causes chemical weathering | when naturally formed acids, air and other substances react with the minerals in rocks |
| Why weathering is important | helps break rocks into smaller fragments to help form soil |
| Soil | a mixture of weathered rock, decaying organic matter, mineral fragments,water and air |
| humus | dark colored organic matter found in soil; made of decayed plants and animals |
| Horizon A has more of this than horizons B & C | humus, sediments, and minerals |
| occurs more rapidly in the A horizon than B & C | weathering |
| minerals found in B & C are dissolved and carried down to these layers by this process | leaching |
| found below Horizon C | parent rock |
| way in which soil erosion can be slowed | no-till farming, shelter belts |
| growing the same crops in the same fields year after year _____ | uses up all the nutrients in the soil |
| the process of erosion and deposition | wearing away, movement, and dropping of materials |
| plucking | process that adds boulder, gravel, and sand to the bottom of a glacier |
| deposit formed when the Mississippi River empties into the Gulf of Mexico | Delta |
| forms when water that is flowing down a steep slope loses energy as it begins flowing on level land | alluvial fan |
| similar to sanblasing | abrasion |
| This what boulders carried by glaciers gouge into rocks | striations |
| moving masses of ice and snow | glaciers |
| large striatons | glacial grooves |
| creep | occurs in climates with freezing and thawing |
| slump | occurs when underlying material is weakened and can no longer hold material on top |
| rockslide | occurs when rocks break loose and tumble down |
| mudslide | occurs in relatively dry areas after heavy rains |
| spring | formed when the water table is exposed at earth's surface |
| Hot spring | spring that is heated by molten rock |
| runoff carries pollutants into streams | how runoff pollutes streams |
| super continent | Pangaea |
| found on several continents and supported theory of continental drift | rocks and fossils |
| Glomar Challenger | obtained rock samples from the ocean floor by use of a drilling rig |
| mid-ocean ridges | underwater mountain chain |
| close to the mid-ocean ridge | youngest material of ocean floor is found here |
| lithospehere | made up of crust and upper mantle |
| floats on top of asthenospehre because of density differences | lithosphere |
| convection current | heating, rising, cooling, sinking |
| places where plate movements can be seen | plate boundaries |
| divergent plate boundaries | where plates move apart |
| convergent plate boundaries | where plates collide |
| transform fault boundaries | where plates slide past one another |
