a. The formation, accumulation, or deposition of material in layers;
specif. the arrangement or disposition of sedimentary rocks in strata.
See also:bedding
b. A structure produced by deposition of sediments in strata; a stratified
formation, or stratum. It may be due to differences of texture, hardness,
cohesion or cementation, color, internal structure, and mineralogic or
lithologic composition. AGI
c. The state of being stratified; a term describing a layered or bedded
sequence, or signifying the existence of strata. AGI
d. A structure produced by deposition of sediments in beds or layers
(strata), laminae, lenses, wedges, and other essentially tabular units.
AGI
In relatively unventilated cavities in coal mines, such as wastes, it is
frequently found that the methane percentage or concentration is higher at
roof level, lower at midheight, and least at floor level. This is termed
stratification of methane. See also:combustible gases layer
Nelson
See:bedding plane; stratification of methane.
Formed, arranged, or laid down in layers or strata; esp. said of any
layered sedimentary rock or deposit. See also:bedded
See:sedimentary rock
a. Derivative or stratified rocks may be fragmental or crystalline; those
that have been mechanically formed are all fragmental; those that have
been chemically precipitated are generally crystalline; and those composed
of organic remains are sometimes partially crystalline.
Syn:sedimentary rocks
b. Rocks arranged in layers. Shell
a. Said of a special type of strata-bound deposit in which the desired
rock or ore constitutes, or is strictly coextensive with, one or more
sedimentary, metamorphic, or igneous layers; e.g., beds of salt or iron
oxide, or layers rich in chromite or platinum in a layered igneous
complex. AGI
b. Having the form of a layer, bed, or stratum; consisting of roughly
parallel bands or sheets, such as a stratiform intrusion. Incorrect
spellings: strataform, stratoform. AGI
c. Bedded or layered. Bateman, 2
A geologist who specializes in stratigraphy.
Pertaining to the composition, sequence, and correlation of stratified
rocks.
The arbitrary, but systematic arrangement, zonation, or partitioning of
the sequence of rock strata of the Earth's crust into units with reference
to the many different characters, properties, or attributes that the
strata may possess (Hedberg, 1958). AGI
a. The influence of stratigraphic features on ore deposition, e.g., ore
minerals selectively replacing calcareous beds. CF:structural control
AGI
b. The degree of understanding of the stratigraphy of an area; the body of
knowledge that can be used to interpret its stratigraphy or geologic
history. AGI
See:stratigraphy
a. For normal faults, the width of the gap between two parts of a
disrupted bed, measured in the direction of the faulted bedding plane.
Schieferdecker
b. For reverse faults, the width of the overlap between two parts of a
disrupted bed, measured in the direction of the faulted bedding plane.
Schieferdecker
A borehole drilled specif. to obtain a detailed record of the character
and composition of the rock formation penetrated and not for the purpose
of locating a mineral deposit. See also:record hole
See:geologic section
The thickness of the strata that originally separated two beds brought
into contact at a fault. Syn:stratigraphic throw
A chronologic succession of sedimentary rocks from older below to younger
above, essentially without interruption; e.g., a sequence of bedded rocks
of interregional scope, bounded by unconformities. AGI
See:stratigraphic separation; throw.
a. The science of rock strata. It is concerned not only with the original
succession and age relations of rock strata but also with their form,
distribution, lithologic composition, fossil content, geophysical and
geochemical properties; indeed, with all characters and attributes of
rocks as strata; and their interpretation in terms of environment or mode
of origin, and geologic history. All classes of rocks, consolidated or
unconsolidated, fall within the general scope of stratigraphy. Some
nonstratiform rock bodies are considered because of their association with
or close relation to rock strata. Syn:stratigraphic geology
AGI
b. The arrangement of strata, esp. as to geographic position and
chronologic order of sequence. AGI
c. The sum of the characteristics studied in stratigraphy; the part of the
geology of an area or district pertaining to the character of its
stratified rocks. AGI
d. A term sometimes used to signify the study of historical geology.
AGI
e. That branch of geology that treats of the formation, composition,
sequence, and correlation of the stratified rocks as parts of the Earth's
crust.
f. That part of the descriptive geology of an area or district that
pertains to the discrimination, character, thickness, sequence, age, and
correlation of the rocks of the district.
A system whereby the in situ orientation of a core sample can be
reproduced on the surface. A line is inscribed on the smoothed bottom of a
borehole, and its azimuth relationship with a compass direction
photographically recorded. When cored and removed from the borehole, the
inscribed line can be used as a guide in orienting the core on the
surface. Long
a. A bed or layer of rock; strata, more than one layer. Fay
b. A layer greater than 1 cm in thickness. Pettijohn, 1
c. A tabular or sheetlike body or layer of sedimentary rock, visually
separable from other layers above and below; a bed. The term is more
frequently used in its plural form, strata. CF:lamina