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Definition
| slow but powerful process that attacks even the hardest rocks largely IN PLACE where rocks originally formed |
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| host of processes by which moving water, wind ice, and crashing surfaces carries away pieces of rock from the exposed weathered bedrock and deposits them elsewhere |
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Definition
| loose, fragmented surface material that is the raw material for many types of sedimentary rock |
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Definition
| breaking a mineral or rock into smaller pieces WITHOUT CHANGING CHEMICAL MAKEUP |
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| breaks mineral or rock into smaller pieces and CHANGES CHEMICAL MAKEUP to a more stable makeup |
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Term
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Definition
1. impact and abrasion (rocks and minerals colliding during transport or when loose transported material scrapes across exposed bedrock surfaces)
2. wetting & drying of rocks (clay minerals & expansion vs. shrinking)
3. freeze-thaw activity (FROST WEDGING - when water trapped in pores or cracks in a rock turns to ice, expands, enlarging cracks in rocks, thawing exposes cracks allowing for water to seep in and weather more)
4. Crystal growth (salts - saltwater deposited, water evaporates, leaving crystals exerting great pressure in cracks, calcite)
5. Exfoliation - breaking in concentric layers, outer layers expand and contract (cracking off, peels apart like an onion) |
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Term
| Weathering as affected by climate |
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Definition
Arid climate:
- mechanical weathering dominates
- overall slow
Humid:
- chemical dominates
- both mechanical & chemical weathering high |
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Term
| Factors Affecting Chemical Weathering |
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Definition
- CLIMATE - wetter = more chemical weathering
- LIVING ORGANISMS - exposes subsurface rocks to weathering agents by burrowing, decomposing organisms increase CO2 level in soil - carbonation
- TIME - longer time = more weathering
- MINERAL STRUCTURE & COMPOSITION - strength & number of chemical bonds |
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Term
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Definition
| upper few meters of regolith that SUPPORTS PLANT LIFE, containing mineral & organic material, water & air |
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Definition
| loose rock blanket, fragmented material covering much of the Earth's land surface |
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Definition
| rock of sediment from which soil develops - mineral content determines both nutrient richness of roil and amount of soil produced |
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Definition
| amount of precipitation received & temperature controls rate of chemical weathering and so rate of soil formation |
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| physical features of a landscape, such as mountains and valleys, steepness of slopes, shapes of landforms, affects soil accumulation areas |
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Definition
| infiltrating water dissolves substances in upper layers of soil and transports them to lower levels, developing distinct weathering zones - each called a SOIL HORIZON |
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Term
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Definition
| USDA classification of vertical succession of soil horizons in a given location - O, A, E, B & C horizons |
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Definition
| loose organic matter - forested environments and wet areas, partially decomposed but still recognizable fibers of plant matter - lots of bacteria, fungi, algae, insects - contributing CO2, organic acids, and oxygen |
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Term
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Definition
| inorganic mineral matter mixed with humus (dark-colored, carbon-rich substance derived from more completely decomposed organic material from O) |
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Term
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Definition
| (E for eluviation - process by which water removes material from soil horizon) light colored zone below A with little or no organic material - light color results from removal of soluble compounds from upper few meters of regolith |
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Term
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Definition
under O A & E, ILLuviation - materials dissolved or transported mechanically from the upper horizons end up here
- red & yellow color with build-up of clay & oxide components by translocation / insituweathering or chemical precipitation |
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Term
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Definition
| distinct carbonate-rich horizon WITHIN OR BELOW B horizon at depth to which annual rainfall penetrates |
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Definition
| lowest zone of significant weathering - parent material that has only partially weathered and still retains most of its original appearance |
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Definition
| consists of O A & E horizons |
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Definition
| weathering in place (space?) |
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Term
| SOIL VS. CLIMATE ( Categories of Soil ) |
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Definition
1. humid temperate
2. humid tropical
3. hot arid
4. wetland, cool moist - temperate - arctic |
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Term
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Definition
| PEDALFER - clay & iron-oxide rich B horizon, CaCO3, leached, silica preserved |
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Term
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Definition
| LATERITE - bright red color, iron & aluminum oxide in B horizon, silica leached or in gel form, when upturned and dried by sun turns very hard - like quartz concrete |
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Definition
| PEDOCAL - salt and calcite precipitates in B, almost no oxide / clay formation, CaCO3 cements called CALICHE or CALCRETE, common in Southern Arizona, cemented horizons, calcium carbonate not always apparent in parent soil - dust from dried lakes rich in calcium carbonate blows in from elsewhere, settles and dries, forms concrete - not many things grow |
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Term
| Wetland, Cool Moist Temperate - Arctic |
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Definition
| organic-rich, peaty with leached minerals below, areas where moisture that comes down from precipitation doesn't evaporate much, soil remains very moist, slows breakdown and decomposition of organic material, lots of layers of material - PEAT MOSS |
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Definition
| the A horizon that has been disturbed and mixed together with the top of B and O horizons by PLOWING |
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Definition
fossil or ancient soil, not forming under present conditions - representing some past period of soil formation (weathering period)
- burried paleosol, relict paleosol - at modern land surface but inconsistent with current conditions |
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Term
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Definition
| when valley forms, we can tell if erosion happened before or after valley by seeing if valley has soil formed already in the bottom |
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