Geology Reference
In-Depth Information
Acknowledgments
I
wish to acknowledge Maurice Deul and Robert F. Chaiken, my supervisors at the US Bureau of Mines, who
generously shared their extensive knowledge of coal geology and coal-mine fires.
Important Terms
Angiosperms
A flowering seed plant, as opposed to nonflowering seed plants (gymnosperms), such
as conifers.
Allochthonous
Formed or produced elsewhere than in its present place; applied to coal or peat that
originated from plant material transported from its place of growth.
Autochthonous
Formed or produced in its current location; applied to coal or peat that originated at the
place where its constituent plants grew and decayed.
Barrier pillar
A solid block or rib of coal, etc., left unworked between two mines for security against
an influx of H
2
O. The unmined block of coal between adjacent mines or between the
mine workings and the outcrop.
Carbonaceous shale
A coal-like material containing too much mineral matter to be considered coal,
frequently formed by an influx of inorganic sediment into the coal swamp.
Coalification
Processes in response to diagenetic and metamorphic agents that determine the genetic
and metamorphic history of coalbeds.
Removal of hydroxyl ions (OH
-
) from a compound or radical.
Dehydroxylation
Demethylation
Removal of a methyl group (CH
3
) from a compound.
Dip
The angle at which a stratum or any horizontal feature is inclined to the horizontal.
Drift coal
Coal that originates from an accumulation of plant material that has been transported
from its place of growth, allochthonous coal.
Epeirogenic
Pertaining to the uplift and subsidence of extensive areas of the earth
'
s crust.
Epigenetic
Pertaining to a mineral deposit formed later than the enclosing rock; in ore petrology,
mineral deposits of later origin than the enclosing rocks or to the formation of
secondary minerals by alteration.
Ether cleavage
The reaction of an ether (CH
3
-
CH
3
) containing molecule with a strong acid (HBr)
to form an alkyl halide (CH
3
Br) and an alcohol (CH
3
OH).
O
-
Eustatic
Pertaining to worldwide changes of sea level that affect all the oceans.
Exothermic
A chemical reaction producing heat.
Hilt
'
s Rule
In a vertical sequence at any given point in a coalfield, the rank of the coal of the
successive seams increases with increasing depth.
Lignin
The major noncarbohydrate portion of wood, an amorphous polymeric substance that
cements the fibrous portions (cellulose) together.
Lithotype
A macroscopically visible band in humic coals.
Maceral
An elementary microscopic constituent of coal, analagous to mineral as used in
petrography; organic units composing the coal mass, having the termination -inite; i.
e., vitrinite, exinites, and inertinites.
Pitch
In structural geology, the angle that a line in a plane makes with a horizontal line in
that plane.
Proximate composition
The compounds contained in a mixture, particularly the concentrations of moisture,
volatile matter, mineral matter and fixed carbon in coal.
