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137 Cards in this Set
- Front
- Back
- 3rd side (hint)
In situ decomposition of rocks and minerals
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Weathering
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transport of weathered material
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Erosion
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most important factor that determines type of weathering
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climate
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C
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disintegration of rock without chemical changes
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physical/mechanical weathering
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chemical/mineralogical composition of rock altered
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chemical weathering
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disintergration of rock due to changes in volume associated with pressure changes as the rock moves to the surface
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unloading
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large mound of granite shaped like an onion associated with unloading
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exfoliation dome
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water seeps into rock and freezes, form of physical weathering, forms talus
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freeze/thaw
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water pushed through rock by freezing water near the surface, produces felsenmeers
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hydrofracturing
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produced by hydrofracturing, large fields of broken up boilders and cobbles
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felsenmeers
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salt water percolates into rock cracks, when water evaporates, salt crystals form breaking the material
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crystal growth
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repeated heating and cooling of rocks causing rock to break apart
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thermal expansion/contraction
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repeated wetting and drying of shales causes rocks to break apart
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wetting and drying
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mud cracks
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dessication cracks
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mud sticks to rock edge, after drying, it shrinks and pulls grain off
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colloidal plucking
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trees, people, etc introduce weathering
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organic
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rocks falling on other rocks
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gravitational impact
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two important things in chemical weathering
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1. Surface area
2. Water |
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Why is water important in chemical weathering?
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Exposes fresh surfaces.
Medium for elemental exchange. Takes part in a chemical reaction. |
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Types of chemical weathering:
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Dissolution
Oxidation/Reduction Ion Exchange Hydrolysis Carbonization Hydration |
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disruption of mineral in water into ions
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dissolution
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mineral loses electron to oxygen
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oxidation
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mineral gains an e-, occurs mostly below water table
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reduction
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substitute one element for another element in a mineral without changing mineral structure
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ion exchange
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way of expressing mobility
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Ion exchange
IP=charge/radius |
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chemical addition of H+ and OH- ions into a structure to create a new mineral
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hydrolysis
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carbonization
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minerals containing K, Na, Ca, Mg interact with cation from carbonic acids to form some sort of CaCO3
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addition of water into mineral structure to form a new mineral
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hydration
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most important control on weathering
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climate
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9 Controls on Weathering
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1. Availability of water.
2. Circulation of water. 3. Vegetation 4. Parent material 5. Temperature 6. Pressure 7. Topography 8. Time 9. Aspect |
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Weathehring rates are dependent on:
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1. Parent material
2. Vegetation 3. Climate 4. Topography 5. Time |
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Product of granular disentigration
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Grus
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weathering of angular edges into rounded edges
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Spheroidal weathering
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bold, isolated outcrop that rises drastically from the ground and can be meters high
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tors
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weathering that looks like honeycomb on the side of the cliff, the cause is hydrolysis
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cavernous weathering
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weathered residue that becomes differentiated at depth into horizons
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soil
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layers of soil
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O-> organic
A-> zone of leaching B-> zone of accumulation C-> no weathering |
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larger scale than tors, these are remnant rocks in hot/dry zones
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inselburgs
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broken up pieces of rock
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regolith
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ancient soil no longer going through soil forming processes
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paleosol
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landforms are interplay of what three things?
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1. Driving forces
2. Resistive framework 3. Time |
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once stress is released, rock returns back to original shape/position
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elastic deformation
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rock remains deformed after stress is released
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plastic deformation
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behaves like a fluid
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plastic
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point at which a material no longer behaves elastically
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elastic limit
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amount of force required to cause failure
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strength
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amount of force required to break in direction of force
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shear strength
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amount of force required to break on a perpendiculat plane
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tensile strength
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amount of force require to crush a rock
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compressive strength
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mechanical resistance to relative motion of adjacent masses
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friction
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slow and steady continuous plastic deformation
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crepe
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Two types of friction:
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1. Sliding friction
-well defined plane -static -dynamic 2. Interna friction |
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Effects of moisture:
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cohesion
surface tension fluid pressure |
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2 Ways to measure shear:
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1. Direct shear test
2. Triaxle Test (accounts for confining pressure) |
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ratio of driving forces to resistive forces
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Safety factor
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Two main types of mass movements
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1. Flow
2. Slip |
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Difference between flow and slip
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Slip- well defined surface
Flow- no well defined surface |
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Naming mass movement depends on:
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mechanism and material
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slow, down-slope movement of saturated soil
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solifluction
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rapid downward sliding along a plane
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landslide
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rock breaks loose and falls through the air
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rockfall
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forward rotation of a block while it falls
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toppling
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curved surface from which mass movement moves away from
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slump
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unsorted incoherent mixture of Earth with water or ice that moves downslope rapidly
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debris avalanche
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narrow valley in side of mountain where debris avalanches are common
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couloirs
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rock fused together during debris avalanche
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frictionite
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slow downslope viscous flow of saturated, fine grained material
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earthflow
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not as fine grained as earth flow
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debris flow
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heterogenous mixture of rock and debris
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mud flow
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high speed debris avalanche that moves downslope
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sturzstroms
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black substance on geologic surface
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desert varnish
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Surface to clouds
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evaporation
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clouds to surface
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precipitation
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surface to subsurface
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infiltration
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surface to ocean
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runoff
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discharge
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volume/time
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intensity
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amount of precipitation/unit time
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how often an event of a certain magnitude reoccurs
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Recurrence interval, #years in record/rank
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lines connecting maximum maximum precipitation in a 24 hour period
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isopluvial map
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annual average precipitation
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isohyet map
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amount of precipitation preceding a rainfall event
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antecedent precipitation
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amount of precipitation that falls and never reaches the ground
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interception
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Types of interception
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1. Transpiration
2. Throughfall 3. Stemflow |
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Infilltration depends on...
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porosity
permeability |
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empty space within soil and rocks
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porosity
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ability of rocks and soil to transmit fluids
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permeability
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movement of water as a broad sheet
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Horton overland flow
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smallest (cm-in) unit which precipitation can form
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rill
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many rills gathered together
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gulley
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flow longer than just a couple of days, but not year round
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euphermal
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elevation between top and base of a stream
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stage height
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is when stream tops stream banks
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flood stage
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max flood stage during an event
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crest
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plot of discharge vs. time
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hydrograph
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Shallow water=
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higher velocity
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5 Ways a river carries material
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1. Dissolution
2. Flotation 3. Ice 4. Suspension 5. Bedload |
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way of transport in which water dissolves minerals and transport them
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dissolution
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debris floats on the water due to surface tension
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flotation
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form of transportation which carries impurities
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ice
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velocity can keep objects from settling
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suspension
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anything that is being carried that is in contact with the bed of the river
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bedload
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type of bedload that bounces along bed
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saltation
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type of bedload in which transport material is always in contact with the bed
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traction
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Difference between valley and channel...
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Channel is where the water is flowing at any given time and the valley is much larger
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area between the channel and valley
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floodplain
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stream is straight with little, if any, variation
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straight stream
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stream has channels that bifrucate and merge back together, but are permanent
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anastomosing
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stream has channels that bifrucate and come back together, but they are not permanent
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braided
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stream with a sinuous path
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meandering
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whole scale movement of a meandering stream most commonly along deltas or oceans
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avulsion
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stream length/valley length
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sinuosity
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any stream that flows within the vally of a parallel stream
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yazoo stream
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elevated areas directly ouside the channel, but stil in the valley
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levee
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stream that has reached equilibrium between discharge load and slope
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graded stream
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more sediment than water, so net deposition
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aggradation
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more water than sediment, so net erosion
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degradation
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Type of degradation that cuts into bed
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incision
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rapid increase in velocity of water can cause bubbles, when bubbles pop they can create shockwaves that break rocks
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cavitation
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Order of Streams
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1st- smallest
2nd- 2 1st 3rd- 2 2nd 4th- 2 3rd |
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Drainage density
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length (sum)/area
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river flows with the slope of the land
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consequent stream
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river has no preferred direction
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insequent stream
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selective headward erosion following courses along weakness
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subsequent streams
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originally consequent stream, but has been modified to flow in opposite direction
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obsequent stream
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once obsequent stream, now consequent stream again
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resequent stream
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Drainage pattern like branches
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dendritic
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parallel lined drainage pattern
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trellis
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parallel, but branching
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rectangular
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streams go away from a central point
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radial
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streams flow to a point
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centripetal
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leading edge of incision
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knickpoint
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one stream captures another
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stream capture
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drainage divide shifts so that one river's drainage captures another
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Abstraction
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tributary captures the original trunk
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autocapture
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old valley that is left high and dry due to stream capture
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wind gap
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one meandering river meanders into another
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intercision
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gently sloping, concave upward, graded surface of erosion that cuts across rocks of varying resistance with a thin veneer of alluvum
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pediment
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