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44 Cards in this Set
- Front
- Back
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Earth Structure
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crust-mantle-liquid outer core-solid core
Asthenosphere below lithosphere |
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mantle
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depth of 2900 km
67% of total mass |
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Inner core
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mass of 1450km
made of iron/nickel and iron silicate poles determined by inner core |
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plate tectonics
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continental sized plates slide across asthenosphere
different rotation speeds creates magnetic waves in space |
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land form
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elevation, slope, aspect, soil type, exposed rock
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dynamic earth
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magma - solidification - rocks - weathering - debris - sediment erosion - load - sediment deposition - magma
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3 forces for plate tectonics
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ridge push - molten rock rises in mid ocean ridges
Mantle drag - crusts riding the mantle slab pull - one crust pulling on another |
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soil
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minerals, organisms, gases, liquids
fundamental interface between 4 spheres |
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Regolith
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inorganic material that results in rock weathering
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climate factor in soil
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temp + moisture are key to soil formation
slope and drainage are different |
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soil contains
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bacteria, fungi, plants, and animals
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bioturbation
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organisms displacing and mixing regolith particles
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earthworms
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tunnels and water
crumbly surface digestive actions, lessens erosion casts excreted rearrange material in soil Nitrification promoted |
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time and soil
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slow processes
depends on parent material and environment degradation and erosion occurs only in a few years soil is a non-renewable resource |
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soil components
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half of volume of average soil is sand or silt
smallest particles are clay clay attracts cations (positively charged ions) organic matter is small percent Litter- leaves and twigs Humus - black gelatinous organic matter |
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soil properties
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half of volume of soil is "pore space"
pores filled with air and water |
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soil water
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capillary - surface tension
hygroscopic - thin film residue combined - chemically bound water gravitational - infiltration from above |
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field capacity
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when soil can't hold anymore water
runoff and evapotranspiration get rid of it |
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wilting point
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plants don't have enough water
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soil - water balance
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cool temp. = less evapotranspiration + water surplus
warmer temp = more evap + water surplus |
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soil color
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black and dark brown = large humus content
red and yellow = high iron oxide content |
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soil texture
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feel for particle size
porosity and permeability; pores and drainage |
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colloids
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particles smaller than one micrometer
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ph scale and soil
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alkaline solutions are not soluble
acid solutions dissolve nutrients before plants absorb |
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cation exchange capacity (CEC)
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a measure of soils fertility
ability to hold or release elements CEC is relative to organic content |
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soil horizons
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O - top decaying layer
A - mineral matter and humus E - zone of eluviation and leaching B - accumulation of clay C - partly altered parent material R - unweathered parent material |
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Pedogenic regime: Laterization
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rapid weathering, dissolution, decomposition
requires significant annual moisture surplus low CEC Red brick color, termed latosols |
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PR: Podzolization
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limited vegetation nutrient requirements
acidic plant litter effective leaching gray color, podsols |
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PR: Gleization
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Poor drainage, acidic
water logged, anaerobic conditions muddy soils and gley soils |
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PR: Calcification
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Semiarid climates with little leaching
little percolating water, lots of capillary action productivity can be different in different places |
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PR: Salinization
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Semiarid areas, capillary action brings up water
intense evaporation salts of chloride, sulfate, sodium |
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Stream
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Any channeled flow of water
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overland flow
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unchanneled downslope of water
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interfluve
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higher land above valley walls separates adjacent valleys
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stream discharge
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the amount of water in a stream over time
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fluvial erosion
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Splash erosion - water hits and excavates land
Sheet - overland flow Rill - Channeled sheet erosion gully - very deep |
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Perennial and intermittent streams
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almost always flowing
seasoned with wet/dry seasons ephemeral: short term response to runoff (down poors) |
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floods
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most erosional excavating happens during floods
stream gages used to measure flow characteristics |
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Laminar flow
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fluid flows parallel without lateral mixing
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Stream channel patterns
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Straight - short indicative
Sinuous - irregular and gentle curvature Meandering - highly variable curvature braided - multiple interwoven channels |
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Consequent streams
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follows slope of land
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Subsequent streams
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Channel follows land form features
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Antecedent streams
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existed before the new uplift occurred
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superimposed streams
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exist on higher plain
eroded away original stream channel pattern |
