Soils And Geomorphology Flashcards
Define geomorphology
The scientific study of landscapes and land forms on the earth’s surface and the processes is acting on them
Characteristics of the Active layer in a permafrost environment
The surface layer characterized by freezing and thawing on a seasonal basis
Define aggradation
Filling in a stream channel with sediment usually associated with low discharges and or heaving sediment loads
Scouring and downcutting of a stream channel usually associated with high discharges
Degradation
Erodibility
The relative susceptibility of a soil to erosion
The k-factor
US soil conservation service term for a value used in the universal soil loss equation representing relative erodibility
Erosion
The removal of rock debris through moving water, wind, or glaciers.
Geomorphic system
A physical system comprised of an assemblage of landforms linked together by Geomorphic processes
What is a hard pan soil layer and how is it formed
A cemented layer in the soil usually 2 to 4 feet under the surface. Formed chemically by lime, iron, or silicate materials deposited at the same level and cementing the soil particles together.
Define mass wasting
The movement of rock and soil down slope under the influence of gravity. Examples include rockfalls, slumps, debris flows.
What events can cause mass wasting
Can be caused by rain fall, seismic activity
How is a moraine Landform formed
Comprised of material left behind by a moving glacier usually soil and rock
Soil types from smallest to largest
Clay (0.002 mm or smaller)
Silt (0.002 - 0.05)
Sand (2 - 0.05)
Describes the soil changes from soil to semisolid to plastic to liquid as water is added to dry soil
Atterberg limits
Moisture content in the soil at the threshold between semi solid and plastic
Plastic limit
Moisture content in the soil at the threshold between plastic and liquid.
Liquid limit
Moisture content in the soil at the threshold between solid and semisolid
Shrinkage limit
Symptoms of compacted soils
Poor aeration, reduced infiltration. Caused by the space between soil particles being greatly reduced or eliminated
What would cause a blueish tint in a soil
Anaerobic soils (conditions resulting from a restriction of oxygen in the soil)
Bearing capacity
The measure of the soil to decrease in volume under the pressure of a given weight
The minimum moisture content at which a soil will flow under its own weight
Liquid limit
The ability of a soil to return to its original shape after being subjected to a load condition
Soil elasticity
Surficial geology
Concerning the study of materials near or at the earths surface
What can be learned from boreholes on site
Depth to bedrock
Hydric soil
Soil which is either permanently or periodically saturated with water
Soils devoid of oxygen most often occurs in wetlands
Anaerobic
Soil particles transported by wind
Aeolian
A type of soil with characteristics resulting from prolong saturation and anaerobic conditions
Hydric soil
Shear strength
The ability of a soil to hold together under pressure from a downhill force
Which soil texture type is most susceptible to erosion
Silt
Soil amendments that increase pH (make it less acidic)
Lime Wood ash Oyster shells Calcium nitrate Industrial CO (burned lime)
Soil amendments that decrease pH (make it less alkaline)
Pine needles/sawdust Iron sulfate Calcium sulfate Sulfur/sulfuric acid Acidic Peat Aluminum Sulphate
Ideal pH range for maximum absorption of nutrients
5.5-6.5
Resistance to crushing or buckling force
Compressive strength
The method of mechanically increasing the density of soil by reducing the total pore space
Compaction
Angle of repose
Steepest angle before slumping
Angle of repose of drained sand
33%
Angle of repose of boulders
45%
Angle of repose of loam
45%
What percentage make up of sand/silt/clay makes loam?
20% clay 40% silt 40% sand
What is a good NPK ratio?
3-1-2
A high pH would mean a soil is -
Alkaline
A low pH would mean a soil is -
Acidic
What test should be performed to determine the maximum density of a soil
Proctor test
Typical features and causes of alkaline soils
pH 7-14
usually associated with areas of lower rainfall, micronutrients may be less available
