Formed in place, without transportation, by the disintegration of the
underlying rock or by the accumulation of organic material; said of some
soils, etc. Fay
a. Solid fragmental material that originates from weathering of rocks and
is transported or deposited by air, water, or ice, or that accumulates by
other natural agents, such as chemical precipitation from solution or
secretion by organisms, and that forms in layers on the Earth's surface at
ordinary temperatures in a loose, unconsolidated form; e.g., sand, gravel,
silt, mud, alluvium. AGI
b. Strictly, solid material that has settled down from a state of
suspension in a liquid. In the singular, the term is usually applied to
material held in suspension in water or recently deposited from
suspension. In the plural, the term is applied to all kinds of deposits,
and refers to essentially unconsolidated materials. CF:deposit
AGI
a. adj. Pertaining to or containing sediment; e.g., sedimentary deposit or
a sedimentary complex. AGI
b. Formed by the deposition of sediment (e.g., a sedimentary clay), or
pertaining to the process of sedimentation (e.g., sedimentary
volcanism).---n. A sedimentary rock or deposit. AGI
a. Mineral matter introduced into the coal substance during its
accumulation. See also:extraneous ash
b. Ash in coal derived from the mud mixed up with plant debris during the
formation of coal. Tomkeieff
A clay that has been geologically transported from the site of its
formation and redeposited elsewhere. The English ball clays, for example,
are secondary kaolins. CF:primary clay
Dodd
A sedimentary rock of ore grade; an ore deposit formed by sedimentary
processes, e.g., saline residues, phosphatic deposits, or iron ore of the
Clinton ore type. AGI
The description and classification of sedimentary rocks.
Syn:sedimentography
The study of the composition, characteristics, and origin of sediments and
sedimentary rocks. AGI
A rock resulting from the consolidation of loose sediment that has
accumulated in layers; e.g., a clastic rock (such as conglomerate or
tillite) consisting of mechanically formed fragments of older rock
transported from its source and deposited in water or from air or ice; or
a chemical rock (such as rock salt or gypsum) formed by precipitation from
solution; or an organic rock (such as certain limestones) consisting of
the remains or secretions of plants and animals. The term is restricted by
some authors to include only those rocks consisting of mechanically
derived sediment; others extend it to embrace all rocks other than purely
igneous and completely metamorphic rocks, thereby including pyroclastic
rocks composed of fragments blown from volcanoes and deposited on land or
in water. Syn:stratified rock; derivative rock. AGI
Rocks formed by the accumulation of sediment in water (aqueous deposits)
or from air (eolian deposits). The sediment may consist of rock fragments
or particles of various sizes (conglomerate sandstone, shale); of the
remains or products of animals or plants (certain limestones and coal); of
the product of chemical action or of evaporation (salt, gypsum, etc.); or
of mixtures of these materials. Some sedimentary deposits (tuffs) are
composed of fragments blown from volcanoes and deposited on land or in
water. A characteristic feature of sedimentary deposits is a layered
structure known as bedding or stratification. Each layer is a bed or
stratum. Sedimentary beds as deposited lie flat or nearly flat.
See:stratified rocks
a. A tuff containing a subordinate amount of nonvolcanic detrital
material. AGI
b. A deposit of reworked tuff and other detrital material. AGI
a. The act or process of settling particles by mechanical means from a
state of suspension in air or water. AGI
b. Method of classification by exploitation of free-falling rates of
minute (subsieve) particles. Pryor, 4
Apparatus used to measure settling rate of small particles dispersed in
liquid. One scale-pan is immersed in the mixture, and the balance is
adjusted by increasing the counterweight at suitable time intervals.
Alternatively, a float is suspended, and the compensating external weight
is reduced as the density of the suspension surrounding the float is
reduced by settlement of its solids. Pryor, 3
A test used when selecting materials for stabilized road construction and
concrete. Soil, after pretreatment, is shaken up in water and allowed to
settle out. The change in specific gravity of the suspended matter with
time is measured, and the equivalent diameter is calculated from Stokes'
law. See also:organic test; Stokes' law. Hammond
The direction in which sediments were laid down. Uranium mineralization
often follows such trends, owing to increased porosity, carbon
precipitants, and other factors. Ballard
A layer or deposit formed under essentially constant physical conditions,
distinguished from other units by differences in grain size and/or fabric,
indicating changes in velocity and/or direction of flow.
The dilution and settling of sediment in a cloud as it advects from a
point source.
The scientific study of sedimentary rocks and of the processes by which
they were formed; the description, classification, origin, and
interpretation of sediments. AGI
A long open tube fixed above the core barrel in the shot-drill method of
exploratory boring. The enlarged space above the sediment tube reduces the
upward velocity of the flushing water and the coarse chippings are
deposited in the tube where they are retained until drawn up to the
surface. Also called calyx; sludge barrel. Nelson