Environmental Engineering Reference
In-Depth Information
Insolation weathering A form of mechanical weathering in which rock-mass
disintegration is attributed to diurnal thermal expansion and contraction; this form of
fatigue failure is apparently most effective in a moist environment.
Intact rock - mass strength The peak strength of a rock mass capable of resisting shear;
Mohr-Coulomb criteria define it as comprising internal cohesion, friction strength and
normal stress.
Interception The process which catches and stores precipitation in a vegetation layer,
where it may be used, evaporated or transmitted on towards the ground.
Internal deformation The change of shape and volume of a mass of Earth material due
to a change in the nature or arrangement of its internal properties; a process by which
material moves under its own mass.
Interspecific competition Competition between distinct species.
Interstitial ice Individual or fused ice crystals occupying the voids of a soil or rock.
Intertidal zone The zone lying between low-water and high-water marks which
fluctuates in width and height range with the monthly tidal cycle.
Intraspecific competition Competition between individuals of the same species.
Intrazonal A class of soils whose profiles are dominated by local factors (e.g. geology,
topography).
Intrusion An igneous rock mass of intrusive origin forming a subsurface batholith , dyke ,
pluton or sill and exposed at the land surface only by subsequent erosion.
Intrusive A description of molten igneous material which penetrates surrounding rock
and cools and solidifies before reaching Earth's surface.
Ion An atom which has lost or gained one or more negatively charged electrons.
Ion antagonism The blocking of the uptake of one cation by the presence in excess of
another (e.g. excess calcium inhibiting iron uptake).
Ionic substitution The replacement of one or more ions in a crystal structure by ions of
similar size and charge, without altering the crystal structure.
Island arc A narrow belt of intense seismovolcanic activity, containing arcs of active
volcanoes flanked by an outer ocean trench and inner marine basin, marking the
surface expression of a B-subduction zone.
Isomorphous substitution The replacement of one atom by another of similar size in the
crystal structure of clay minerals, without disrupting the structure.
Isostasy The equilibrium condition in which lighter crust 'floats' on denser mantle and
whose relative proportions from one place to another maintain Earth's shape.
Isostatic adjustment The vertical and lateral displacement of crust and lithosphere in
order to maintain or restore isostatic equilibrium.
Joint A fracture between the constituent parts of a rock mass, usually caused by its
contraction on cooling or drying.
Jökulhlaup A flash flood of glacier meltwater from a subglacial or glacier-margin lake
due to failure of an ice dam.
Kame A steep, isolated mound of glaciofluvial sand and gravel deposited in contact with
glacier ice.
Kame moraine An irregular ridge of glaciofluvial sediments marking a glacier terminus,
formed either by the wholesale meltwater reworking of a moraine or the coalescence
of kames and kame terrace fragments.
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