Environmental Engineering Reference
In-Depth Information
Feedback
The property of a system such that, when change is introduced via one of the
variables in the system, its transmission through the system leads back to a change in
the original variable.
Felsenmeer
A German term for
blockfield
.
Felsic
A mnenomic from
fel
dspar and
si
li
c
ate, which identifies the silicate-rich igneous
rocks characterized by their light-coloured, acidic minerals.
Fetch
The extent of open water over which a dominant wind develops a wave system.
Field capacity
The maximum volume of water held in the voids of a soil when
gravitational drainage is complete, comprised of
capillary
and
hygroscopic
water.
Firn
A stage in the transformation of snowpack towards glacial ice, with a density of
0·4-0·5 × 10
3
kg m
−3
.
Fissure
A wide fault or tension crack in the land surface often associated with a linear
volcanic eruption.
Fixation
The transformation in soil of a plant nutrient from an
available
to an
unavailable state.
Fjord
A long, deep rock basin excavated by an
outlet
or valley glacier between high rock
walls and flooded by the sea during deglaciation.
Flandrian stage
The current global
temperate stage
, more or less synonymous with the
Holocene, which commenced
c
. 10,000 years BP.
Flexural isostasy
Localized isostatic adjustment peripheral to, and in an opposite
direction from, an area of crustal loading or unloading; due to flexure or
creep
in the
lithosphere.
Flocculation
The aggregation of individual suspended clay particles into larger masses,
with consequential implications for their sediment dynamics.
Flood basalt
An extensive basalt flow extruded from continental rifts and fissures which
forms distinctive terrestrial land surfaces.
Flood plain
A lowland land surface prone to episodic river floods and associated alluvial
sedimentation.
Flow regime
The range of styles of stream flow and their related
bed forms
and modes of
sediment transport.
Flow tuff
A lithified form of volcanic ash which once moved as a
pyroclastic flow
and
contains evidence of that movement, often in the form of parallel extruded minerals.
Fluid stressing
The erosive power of a stream contributed by fluid shear stress at the
stream bed.
Flysch
Submarine
turbidite
sediments eroded from an orogenic belt during uplift and
therefore located in adjacent
trench
or
back-arc
zones.
Föhn
An equivalent of the
chinook
wind in the European Alps.
Fold
A compressional or gravitational
plastic
deformation of Earth materials which has
bent and shortened a previously planar mass.
Foliation
A close-spaced planar texture in rock acquired by the alignment of platy
minerals during
metamorphism
.
Force
Mass × acceleration measured in newtons, N (SI units).
Fore arc
A zone lying between and parallel to the
trench
and
volcanic arc
of a
B-
subduction
zone, consisting of an outer ridge and an inner basin.
Fore
-
arc basin
A narrow marine basin lying just offshore of a volcanic
island arc
in a
B-
subduction
zone.