Term
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Definition
| breakdown of rock materials |
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Definition
| transport of broken-down materials |
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Definition
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| low thermal conductivity, causes rocks to expand ant the surface but not at depth, differential stress & spalling |
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Definition
| confining P goes down when overlying rocks are removed - sheets form perpendicular to the direction of P release, mirroring surface topography |
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Term
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Definition
| hydration of salts/minerals - expansion exfoliation (large scale), spheroidal weathering (small scale) - corners weather first |
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Term
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Definition
| caused by frost action, plant roots, mineral precipitation |
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Definition
| rainwater is mildly acidic, dissolving some minerals in rocks |
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| two stages of chemical weathering |
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Definition
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Term
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Definition
| geochemical - rotten rock/saprolites (mostly in tropics) |
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Term
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Definition
| biologic - pedochemical weathering, produces soils |
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Term
| oxidation, where it occurs |
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Definition
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Term
| reduction, were it occurs |
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Definition
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Term
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Definition
| atoms dissolved from a mineral, structure becomes unstable |
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Term
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Definition
| reaction between mineral elements & H ion of dissociated water (orthoclase -> kaolinite) |
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Definition
| weathering surface that forms a crust over the rock, more resistant to further weathering because dissolvable cement is gone |
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Definition
| small cavities in rock formed by dissolution of CaCO3 cement |
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Term
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Definition
| substitution of ions in solution for those held by mineral grains, most effective in clay minerals (travertine terraces) |
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Term
| relative mobility of cations |
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Definition
Ca2+ > Mg2+ > Na+ > Fe2+ > Si4+ > Ti4+ > Fe3+ > Al3+
(most mobile to least mobile) |
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Term
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Definition
olivine, anorthire
pyroxenes, Ca-Na plag
amphiboles, Na-Ca plag
biotite, albite
K-feldspars
muscovite
quartz
(least to most stable) |
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Term
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Definition
| residuum resulting from weathering over an extended period of time |
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Term
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Definition
| mostly organic, made of muds, clays & muds are leached down to subsequent horizons |
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Term
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Definition
| transitional, most minerals are leached, rich in clays & Fe & Al oxides |
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Term
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Definition
| underlying parent material essentially unmodified by soil-forming processes, regolith |
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Term
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Definition
| not much A, little organic material |
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Term
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Definition
| not much A, organic matter destroyed by insects, water, high temp |
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Term
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Definition
| s=f(cl,o,r,p,t) -> climate, biota, topography, parent material, time |
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Term
| most dominant factor controlling soils on a large scale |
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Definition
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Term
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Definition
| general trends of soil development under specific climatic and vegetation controls |
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Term
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Definition
| podzolization, laterization, calcification |
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Term
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Definition
removal of Fe &/or Al from A to B
humid temperate climates, esp forest vegetation, acidic soils
end product: resistant primary minerals (quartz), Fe & Al hydrates, kaolinitic clays |
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Term
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Definition
occurs due to high precipitation and temperature, intense leaching and oxidation (tropics, humid)
organic accumulation is inhibited
silica is leached, leaving Fe & Al hydrated oxides in gibbsite
RED |
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Term
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Definition
occurs in subhumid to arid, where precipitation in insufficient to drive soil water down to water table
ions mobilized in A, reprecipitation in B
depth of carbonate zone is a function of annual precip & approx the vertical depth of leaching |
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Term
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Definition
| grains sliding past one another on planar surfaces, varies with moisture, smoothness of plane surface mineralogy |
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Term
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Definition
| particles move upward & over one another, varies with moisture, mineralogy, density of packing |
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Term
| total normal stress equation |
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Definition
| total normal stress = effective normal stress + pore pressure |
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Term
| factors increasing shear stress (promote failure) |
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Definition
removal of lateral support - erosion (rivers, ice, waves), human activity (quarries, road cuts)
addition of mass - natural (rain, talus) human (fills, ore stockpiles, buildings)
earthquakes
regional titling
removal of underlying support - natural (undercutting, solution, weathering) human (mining)
lateral pressure - natural (swelling, freezing expansion, water addition) |
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Term
| factors decreasing shear strength (promote failure) |
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Definition
weathering - disintegration, hydration, base exchange, solution, dyring
pore water - buoyancy, capillary tension
structural changes - remolding, fracturing |
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Term
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Definition
Gs = resisting / driving = shear strength / shear stress
Gs > 1 stable |
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Term
| three basic types of mass movements |
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Definition
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Term
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Definition
| cohesion blocks of material move on a well-defined surface of sliding, no internal shearing within the sliding block |
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Term
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Definition
| move entirely by differential shearing within the transported mass - no clear plane at the base, velocity decreases from surface down |
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Term
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Definition
| disrupting forces act perpendicular to the ground surface by expansion of materials, facilitates downslope movement |
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Term
| amount of soil moved by splash depends on |
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Definition
| kinetic energy of raindrops, type & amount of soil exposed, steepness of slope |
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Term
| shear stress equation (water) |
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Definition
| shear stress = (specific weight of water)(flow depth)(topographic gradient) |
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Term
| universal soil loss equation |
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Definition
| soil loss = (erodability)(rainfall)(slope length)(steepness)(cropping)(conservation) |
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Term
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Definition
time
lithology
climate
process |
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Term
| slopes in humid, temperate regions |
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Definition
convex (soil creep) -> straight -> concave (soil wash)
continuous veg cover = soil, high weathering rates, fine material
slow movements - creep & heave |
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Term
| slopes in semiarid/arid regions |
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Definition
cliff -> debris slope -> plain
less veg & precip, mass movements occur at a high angle, creep less important than wash
debris doesnt get transported very far, little water, less weathering, less soil |
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Term
| slope development with time |
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Definition
| slope decline, slope replacement, parallel retreat |
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Term
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Definition
steep upper slope erodes more rapidly than basal zone, flattening of overall angle, with a convexity on the upper slope and concavity on lower slope
>>earthquake, falts |
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Term
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Definition
steepest angle progressively replaced by upwards expansion of gentler slope developed near base, enlarges overall concavity of profile, which can be segmented/smoothly curved
>>creep, wash, rockfall |
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Term
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Definition
maintain constant angles on steepest part of slope
>>talus, creep, wash |
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Term
| type of downslope movement of precip depends on |
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Definition
| infiltration capacity of surface (soil texture & structure, vegitation, antecedent moisture, other surface conditions), intensity and duration of precip |
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Term
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Definition
| function of slope angle, nature of surface |
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Term
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Definition
| function of vegitation, nature of surface |
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Term
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Definition
| F of overland flow > R of surface being eroded |
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Term
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Definition
| rainbeat, thread flow, sheet flow, rill flow, small channels |
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Term
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Definition
percolines - zones of greater soil in depth & moisture content
pipes - horizons/surfaces of limite permeability w/ enlarged pores |
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Term
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Definition
occurs in saturated zone, percolines meet the surface as seeps/springs
sapping network controlled by direction of groundwater flow |
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Term
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Definition
| occurs in unsaturated zone, above water table, differences in permeability create hydraulic head, differential erosion |
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Term
| basic steps in network growth |
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Definition
initiation of channels
elongation through headward growth
elaboration/branching as tributaries are added |
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Term
| ratios represent linear, areal & relief morphometric components of the basin |
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Definition
linear - stream number
areal - drainage density
relief - relief ratio, hypsometric integral |
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Term
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Definition
discharge = width*depth*velocity
= Area*velocity |
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Term
| controls on sediment yield |
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Definition
climate
vegetation
basin size - small, high sediment yield due to steep slopes & channels
elevation & relief
rock type/erosional resistance - cataclastic sed rocks have higher sed yield than crystalline rocks
land use |
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Term
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Definition
describe how energy is distributed in a flow = driving/resisting
R<500 laminar
R>750 turbulent |
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Term
| external resistance caused by |
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Definition
particle size
bedforms
vegetation
channel irregularities
structures |
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Term
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Definition
| amount of sediment being carried by water - increases in sed decrease resistance, turbulence effects decrease, mixing within fluid decreases |
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