Glossary Terms Flashcards
A fan shaped deposit of alluvium, laid down by a stream where it emerges from an upland to less steeply sloping terrain
alluvial fan
Material such as clay, silt, sand and gravel deposited by modern rivers and streams
alluvium
A unit layer, 1 cm or more thick, that is visually or physically more or less distinctly separable from other layers above and below in a stratified sequence
bed
The solid rock that underlies the soil and the regolith, or that is exposed at the surface
bedrock
Soil containing sufficient calcium carbonate, often with magnesium carbonate, to effervesce visibly with cold 0.1N (10%) hydrochloric acid
calcareous soil
A zone of essentially saturated soil just above the water table. The size distribution of the pores determines its extent
capillary fringe
As a particle size term: a size fraction less than 0.002mm in equivalent diameter
clay
Containing large amounts of clay, or having properties similar to those of clay
clayey
A substance in a state of fine subdivision, whose particles are 10(-4) to 10(-7) in diameter
colloid
The resistance of a material to deformation or rupture
consistence
The gradual reduction in volume of a soil mass resulting from an increase in compressive stress
consolidation
Slow mass movement of soil and soil material down rather steep slopes primarily under the influence of gravity, but aided by saturation with water and by alternate freezing and thawing. In engineering: general slow displacement under load
creep
The force required to crush a mass of dry soil, or conversely the resistance of a mass of dry soil to crushing
crushing strength
To separate the individual components of compound particles by chemical or physical means or both. To cause the particles of the dispersed phase of a colloidal system to become suspended in the dispersion medium
deflocculate
A fan shaped area at the mouth of a river formed by deposition of successive layers of sediment brought down from the land and spread out on the bottom of a basin. Where the stream current reaches quiet water, the bulk of the coarser load is dropped and the diner material is carried farther out. Recognized by nearly horizontal beds termed bottomset, overlain by more steeply inclined and coarser textured beds called foreset beds
delta
material left in a new position by a natural transporting agent such as water, wind, ice or gravity or by the activity of man
deposit
An elongate or oval hill of glacial drift, commonly glacial till, deposited by glacier ice and having its long axis parallel to the direction of ice movement
drumlin
Wind-built ridges and hills of sand formed in the same manner as snowdrifts. They are startwater, ed by come obstruction, such as a bush, boulder, or fence that causes an eddy or thwarts the sand laden wind. Once begun they offer further resistance and they grow to form various shapes
dunes
sand or silt or both deposited by the wind
eolian deposit
The wearing away of the land surface b running water, wind, ice or other geological agents including such processes as gravitational creep. Detachment and movement of soil or rock by water, wind, ice or gravity
erosion
A transported rock fragment different from the bedrock where it lies. The term is generally applied to fragments transported by glacier ice or by floating ice
erratic
A winding ridge of irregularly stratified sand, gravel, and cobbles deposited under the ice by a rapidly flowing glacial stream
esker
A term used in soil mechanics for the portion of a soil finer than a number 200 US. standard sieve
fines
A term describing the consistence of a moist soil that offers distinctly noticeable resistance to crushing, but can be crushed with moderate pressure between the thumb and forefinger
firm
The land bordering a stream, built up of sediments from overflow of the stream and subject to inundation when the stream is at flood stage
flood plain
All sediments, past and present, deposited by flowing water, including glaciofluvial deposits. Wave worked deposits and deposits resulting from sheet erosion and mass wasting are not included
fluvial deposits
A consistence term pertaining to the ease of crumbling soils
friable
Freezing and thawing of moisture in materials and the resultant effects on these materials and on the structures of which they are a part of with which they are in contact
frost action
The raising of a surface caused by ice and glacial meltwater or rafted by icebergs. This term includes till, stratified drift and scattered rock fragments
glacial drift
Unstratified glacial drift deposited directly by ice and consisting of clay, sand and gravel and boulders intermingled in any proportion
glacial till
Material moved by glaciers and subsequently sorted and deposited by streams flowing from the melted ice. The deposits are stratified and may occur in the form of outwash plains, deltas, kames, eskers and kame terrances
glaciofluvial deposits
An unsorted mixture of rocks, boulders, sand, silt, and clay deposited by glacial ice. The predominant material is till, but some stratified drift is present. Most of the till is thought to have accumulated under the ice by lodgement; but some till has been let down from the upper surface of the ice by ablation. Usually in the form of undulating plains having gently sloping swells, sags, and enclosed depressions
ground morraine
A layer of soil or soil material approximately parallel to the land surface. It differs fro adjacent genetically related layers in properties such as colour, structure, texture, consistence and chemical, biological and mineralogical composition
horizon
The proportionality factor in Darcy’s law as applied to the viscous flow of water in a soil, that is, the flux of water per unit gradient of the hydraulic potential
hydraulic conductivity
The elevation with respect to a specified reference level at which water stands in a piezometer connected to the point in question in the soil
hydraulic head
The conditions through which water naturally passes from the time of precipitation until it is returned to the atmosphere by evaporation and is ready again to be precipitated
hydrologic cycle
A soil characteristic determining of describing the maximum rate at which water can enter the soil under specified conditions including the presence of excess water
infiltration rate
A soil made up of mainly mineral particles (<17% carbon)
inorganic soil
Atom, group of atoms, or compound that is electrically charged as a result of the loss of electrons (cation) or the gain of electrons (anion)
ion
An irregular ridge or hill of stratified glacial drift deposited by glacial meltwater
kame
Depression left after the melting of a detached mass of glacier ice buried by drift
kettle
Material deposited in lake water and later exposed either by lowering of water level or by up lifting of the land. These sediments range in texture from sand to clays
lacustrine deposit
The various shapes of the land surface resulting from a variety of actions such as deposition or sedimentation (eskers, lacustrine basins) erosion (gullies, canyons) and earth crust movements (mountains)
landforms
The sudden, large decrease of the shearing resistance of a cohesionless soil. It is caused by a collapse of the structure by shock or other strain and is associated with a sudden, temporary transformation of the material into a fluid mass
liquefaction
The water content corresponding to an arbitrary limit between the liquid and plastic states of consistence of a soil. The water content at which a part of soil, cut by a standard-size groove, will flow together for a distance of 12mm under the impact of 25 blows in a standard liquid-limit apparatus
liquid limit
Material transported and deposited by wind and consisting of predominantly silt-sized particles
loess
A soft, unconsolidated earthy deposit consisting of calcium carbonate or magnesium carbonate, or both and often shells, usually mixed with varying amounts of clay or other impurities
marl
A general term for a variety of processes by which large masses of earth material are moved by gravity from one place to another
mass wasting
Rock derived from preexisting rocks, but differing from them in a physical, chemical and mineralogical properties as a result of natural geological processes, principally heat and pressure, originating within the earth. The preexisting rocks may have been igneous, sedimentary, or another form of metamorphic rock
metamorphic rock
A homogeneous naturally occurring phase, sometimes restricted to inorganic, crystalline phases
mineral
A specific aluminous member of the smectite group i.e. an expanding clay
montmorillonite
An accumulation of earth, generally with stones, carried and finally deposited by glacier
moraine
The rock from which the parent materials of soils are formed
parent rock
The determination of the various amounts of the different separates in a soil sample, usually by sedimentation, sieving or micrometry or a combination of these methods
particle size analysis
The amounts of various soil separates, in a soil sample, usually expressed as weight percentages
particle size distribution
The effective diameter of a particle measured by sedimentation, sieving or micrometric methods
particle size
A water table due to the “perching” of water on a relatively impermeable layer at some depth within the soil. The soil within or below the impermeable layer is not saturated with water
perched water table
The downward movement of water through soil; specifically, the downward flow of water in saturated or nearly saturated soil
percolation
Perennially frozen material underlying the solum. A perennially frozen soil horizon
permafrost
The ease with which gases and liquids penetrate or pass through a bulk mass of soil or layer of soil. The property of a porous medium that relates to the ease with which gases or liquids can pass through it
permeability
The negative logarithm of the hydrogen ion activity of a soil. The degree of acidity or alkalinity on a negative log scale of 1 to 14
pH
The breakdown of rock and mineral particles into smaller pieces by physical forces such as frost action and wind
physical weathering
The water content corresponding to an arbitrary limit between the plastic and semisolid states of consistence of a soil. The water content at which a soil will just begin to crumble when rolled into a thread approximately 3mm in diameter
plastic limit
The part of the bulk volume of soil not occupied by soil particles. Also known as interstices or voids
pores
The volume percentage of the total bulk not occupied by solid particles
porosity
Clayey material having the tendency to change from a relatively stiff condition to a liquid mass when it is disturbed
quick clay
To fill all the voids between soil particles with liquid. To fill to capacity as the absorption complex with a cation species; for example H saturated
saturate
A rock formed from materials deposited from suspension or precipitated from solution and usually more or less consolidated
sedimentary rock
- A soil separate consisting of particles between 0.05mm (0.75 in engineering system) and 0.002mm in diameter
- A soil textural class
silt
Any mineral occurring as part of or in the soil. A natural inorganic compound with definite physical, chemical and crystalline properties occurring in the soil
soil mineral
The unconsolidated material on the immediate surface of the earth that serves as a natural medium for the growth of plants. The naturally occurring unconsolidated material on the surface of the earth that has been influenced by parent material, climate, macro, and micro-organisms, and relief, all acting over a period of time to produce material that may differ from the material from which it was derived in many physical, chemical, mineralogical, biological and morphological properties
soil
An equation relating to the terminal settling velocity of a smooth, rigid sphere in a viscous fluid of known density and viscosity to the diameter of the sphere when subjected to a known force field. It is used in the particle size analysis of soils by the hydrometer method
Stoke’s law
The arrangement of sediments in layers or strata marked by a change in colour, texture, dimension of particles and composition. Layers of sediments that separate readily along bedding planes because of different sizes and kinds of material or some interruption in deposition that permitted changes to take place before material was deposited
stratification
A ridge-like accumulation of drift built chiefly along the terminal margin of a valley glacier or the margin of an ice sheet mainly the result of deposition by ice, or formation by ice thrust or both
terminal moraine
The relative proportions of the various soil separates in a soil (clay, silt, sand, and coarse fragments)
texture
The layer of soil moved in cultivation; the Ah horizon; presumably fertile soil material used to top-dress, road banks, gardens and lawns
topsoil
Elevation at which the pressure in the water is zero with respect to the atmospheric pressure
water table
