A term applied to combustion in which all of the fuel is not burned; e.g.,
leaving unburned carbon in ashes. CF:imperfect combustion
Newton, 1
a. Melting accompanied by decomposition or by reaction with the liquid, so
that one solid phase is converted into another; melting to give a liquid
different in composition from the original solid. An example is orthoclase
melting incongruently to give leucite and a liquid richer in silica than
the original orthoclase. CF:congruent melting
b. A crystalline compound that dissociates into another compound and a
melt of different composition upon heating. CF:congruent melting
A process by which material contributing to coal formation responds to
diagenetic and metamorphic agencies of coalification and becomes a part of
the coal without undergoing any material modification.
See also:coalification
The quantity of coal or coke taken by a single sweep of the sampling
instrument. BS, 2
A former outcrop concealed by or buried beneath younger unconformable
strata. AGI
See:encrustation
The condition in sedimentation in which each floc or particle settles
freely; i.e., its movement is not influenced in any way by other flocs or
particles in suspension. Mitchell
This core may be 6 by 7, 7 by 7, 6 by 19, or 7 by 19 (number of strands
laid together and ropes twisted together) construction, and the individual
wires shall be of an appropriate grade of steel in accordance with the
best practice and design, either bright (uncoated), galvanized, or drawn
galvanized wire. See also:wire-strand core
Hydrous calcium and magnesium borate mineral, CaMg[B3 O3
(OH)5 ]2 .6H2 O , as monoclinic crystals from the
Inder borate deposits, Kazakhstan. Named from locality.
See also:metahydroboracite
A monoclinic mineral, MgB3 O3 (OH)5 .5H2 O ;
forms nodular aggregates or acicular crystals; named from the locality,
Inder, Kazakhstan.
See:key bed
A contour line shown on a map in a distinctive manner for ease of
identification, being printed more heavily than other contour lines and
generally labeled with a value (such as figure of elevation) along its
course. It appears at regular intervals, such as every fifth or sometimes
every fourth contour line (depending on the contour interval).
Syn:accented contour
A fossil that, because of its wide geographic distribution and restricted
time range, can be used to identify and date the strata in which it
occurs. CF:guide fossil
A structural surface used as a reference in analyzing the geologic
structure of an area. AGI
A mineral developed under a particular set of temperature and pressure
conditions, thus characterizing a particular degree of metamorphism. When
dealing with progressive metamorphism, it is a mineral whose first
appearance (in passing from low to higher grades of metamorphism) marks
the outer limit of the zone in question. CF:typomorphic mineral
AGI
This is found by the formula: water content of test sample-water content
at plastic limit/index of plasticity. This gives a value of 100% for clay
at the liquid limit, and zero at the plastic limit, and is the reverse of
the consistency index. Hammond
The difference between the water content of clay at its liquid and plastic
limits, showing the range of water contents over which the clay is
plastic. Hammond
A number n found by dividing the velocity of light in a vacuum c by the
velocity of light in a transparent substance. Isometric crystals are
isotropic and have one index of refraction; all other symmetries are
anisotropic. Hexagonal, trigonal, and tetragonal crystals have two
principal indices; orthorhombic, monoclinic, and triclinic crystals have
three principal indices. Determination of indices of refraction of a
mineral is a major means of mineral identification. See also:dispersion;
interference. Syn:immersion method; optical mineralogy;
refractive index. CF:transmitted light
Properties that can be used to identify the soil type. The properties are
of two kinds: (1) soil grain properties and (2) soil aggregate properties.
Nelson
Tests to determine index properties that in turn serve to identify the
soil type and indicate its consistency. Nelson
A hexagonal mineral, Mg2 Al4 Si5 O18 ; the
high-temperature polymorph of cordierite; in sediments fused by a burning
coal seam in India. Named for the locality.