| Term | Definition |
|---|
| Weathering | the decompocition and disintegration of rocks and minerals at the earth's surface by a mechanical and chemical process |
| pot holes | are evidence of weathering |
| Why do rocks weather? | Rocks are exposed to wind, water, ice and biological processes |
| physical and chemical are | two types of weathering |
| physical weathering | the breakdown of rocks into smaller pieces, without a change in composition |
| Types of agents | frost, plants, wind, temperature, abrasion, animal action, and human action |
| Frost Action | freezing and thawing causes rocks to crumble (example pot holes) |
| Plant Action | plants roots grow in the cracks of rocks and push them apart |
| Abrasion | rocks grind against each other by streams, wind, moving ice, and gravity |
| Temperature Changes | rocks are often exposed to large temperature changes such as those resultingfrom forest fires. This can cause rocks to crack |
| Chemical weathering involves reactions between | minerals and oxygen, water, and/or carbon dioxide |
| Chemical weathering prevails in | warm and humid places |
| Oxidaiton | minerals unite with oxygen forming new weaker substance (ex. rust) |
| Physical weathering by frost action is dominate in what type of climate? | Temperature changing above or below freezing |
| chemical weathering is dominant in a | humid and warm climate |
| hydration | rocks dissolve in water (ex. salt) |
| carbonation | combines with water to make a weak acid, carbonic acid |
| sink holes | are an example of chemical weathering and is when water dissolves limestone |
| caves form when | water seeps underground and disolves limestone below |
| frost wedgings | freezing water expands causing stress on surrounding rock material |
| plant action | plant roots grow in the cracks of rocks and gradually push them apart |
| temperature changes | rocks are often exposed to large temperature changes such as those resulting from forest fires. This can cause rocks to crack |
| What is the end result of weathering? | Soil Formation |
| Soill | is the mixture of rock particles and organic matter |
| Soil is the product of | the weathering of rocks, includes organic matter |
| Factors effecting the type of soil are | climate (most important factor), bedrock material (soil takes on characteristics of the parent rock), and time |
| Humus | organic matter (leaves) decompose and forms soil |
| horizons | soil over time develop horizontal layers |
| Climate | is the most important factor in determining the type of soil that will form |
| soil are transported by | wind, moving water, and glaciers |
| residual sediment | weathered rock remaining in its place of origin |
| transported sediment | transported from its place of origin (most common type) |
| Erosion | the process by which sediments are transported |
| agents of erosion | running warer, waves, glaciers, wind, and humans |
| running water | is the dominant agent of erosion |
| What is the force behind erosion? | Gravity |
| mass movements | sediments move directly down hill from gravity (ex. earthquakes, land slides, mud flows, and wave erosion) |
| What factors lead to mass movement? | gravity versus friction, what reduces the friction that holds the sediments in place |
| What 3 ways fo streams carry sediment? | dissolved minerals carried in solution, collloids, large particles bounced along bottom |
| colloids | particules up to a hundred times smaller than that those in suspesion that are, however, likewise uspended in a solution. |
| stream velocity | varies within the bends |
| maximum stream velocity is found | on the outside of bends |
| minimum velocity is found | on the inside of bends |
| Besides the outside bends, where else is the streamsvelocity the greatest? | In the deepest part (because of friction) |
| Deposition is dominant when | stream velocity is slowest |
| meander | a curve in a stream |
| source | where the river begins |
| mouth | where the river ends |
| delta | deposit of sediment formed at the mouth where the flows |
| The youthful stage of a stream has | waterfalls, lakes, and rapids, also the downcutting is greater than side cutting |
| V shaped valleys are produced by | rivers |
| U shaped valleys are produced by | glaciers |
| The Maturity Stage of a stream has | flood plain forms (side cutting is greater than down cutting), gentle gradient develops, meanders, ox bow lakes |
| Old Age Stage has a | valley floor becomes wider than the stream |
| Overall effect of sediments eroded by streams: | running water bumps rocks together (abrasion) producing rounded and smooth sediments |
| wind erosion | sand blasting produces a pitted surface, lower levels of rock are sandblasted causing a mushroom effect, can cause rocks with flat sides |
| waves are caused by | wind, tsnamis, and tides |
| Sediments often have characteristics that | indicate how they were transported |
| How were these eroded? | Stream or waves, wind, and gravity |
| wind produces | pitted or frosted surfaces |
| gravity erosion | produces sharp angular sediments |
| Deposition | the process by which sediments are released or dropped from an erosional system |
| Why does most deposition occur in lakes or oceans? | Because, running water is the biggest erosional system |
| What are other agents of deposition? | They are wind and glaciers |
| Dissolved particles are | left behind as the water evaporates (examples: salt, stalactites) |
| What causes deposition from moving water? | As a stream slows down, it will deposit sediments it can no longer carry. Larger heavier particles settle out first. |
| What happens when water movement completely stops? | All sediments settle out except for colloids |
| What factors affect deposition rates? | particle shape and size |
| particle shape | rounded particles settle faster than flatter material |
| particle size | large particles settle faster than small particles |
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