A fault in which the net slip lies between the direction of dip and the
direction of strike. Syn:diagonal-slip fault
The narrow prismatic part of a blast furnace immediately above the
crucible. Fay
A scarp along a fault line, where the topographically low area is on the
upthrown block. CF:resequent fault-line scarp
a. In seismic prospecting, the person in charge of the recording crew,
including the shooters and linemen. The observer must maintain the
electronic equipment and decide on the best shooting and detector
arrangement as well as the best instrumental settings for getting records
of optimum quality. The observer operates the recording equipment in the
field, often with the help of an assistant. In conventional recording, or
in tape recording when photographic monitors are run, the observer or an
assistant develops the record in the recording truck immediately after it
is shot. Also called operator. Dobrin
b. In gravity and magnetic prospecting, a person who secures the
instrument readings, e.g., on a torsion balance or magnetometer.
AGI
A black or dark-colored volcanic glass, usually of rhyolite composition,
characterized by conchoidal fracture. It is sometimes banded or has
microlites. Usage of the term goes back as far as Pliny, who described the
rock from Ethiopia. Obsidian has been used for making arrowheads, other
sharp implements, jewelry, and art objects. Syn:Iceland agate
AGI
Lightweight, siliceous fireclay, acid-resisting brick, burned to a
glasslike mass.
a. That axis that bisects the obtuse angle of the optic axes of biaxial
minerals. Fay
b. The angle >90 degrees between the optic axes in a biaxial crystal, bxo.
CF:optic angle
See:cat's-eye; tiger's-eye.
To take in and retain (a substance) in the interior rather than on an
external surface; to sorb. Used esp. of metals sorbing gases; e.g.,
palladium occludes large volumes of hydrogen. Webster 3rd
Contained in pores (said of gas occluded in coal). Mason
Any of several gases that enter a mine atmosphere from pores, as feeders
and blowers, and also from blasting operations. These gases pollute the
mine air chiefly by the absorption of oxygen by the coal, and in addition
by chemical combination of oxygen with carbonaceous matter, for example,
from decaying timbers, rusting of iron rails, burning of lights, and
breathing of humans and animals. These gases include oxygen, nitrogen,
carbon dioxide, and methane. Kentucky
a. Taking up or incorporation of liquids in solids or of gases in liquids.
AGI
b. See:absorption
An occupant of a tract of land, as the word ordinarily is used, is one who
has the use and possession thereof, whether he resides upon it or not.
Ricketts
As used in the mining law, it is equivalent to possession, and the right
to locate is included in the right to occupy, and incident to a location
is the right of possession; but mere occupancy of the public lands and
making improvement thereon gives no vested right therein as against a
location made in pursuance of law. Ricketts
a. The name current is usually restricted to the faster movements of the
ocean, while those movements that amount to only a few miles a day are
termed drifts. AGI
b. A nontidal current constituting a part of the great oceanic
circulation. Examples are gulf stream, kuroshio, and equatorial currents.
AGI
See:Mid-Atlantic Ridge; mid-ocean ridge.
See:trench
Apparatus used aboard ships to bring up quantity samples of the ocean
bottom deposits and sediments. Hunt
The broad field of science that includes all fields of study that pertain
to the sea. This includes the studies of boundaries of the ocean, its
bottom topography, the physics and chemistry of seawater, the
characteristics of its motion, and marine biology. Hy
A name given to various native earthy materials used as pigments. They
consist essentially of hydrated ferric oxide admixed with clay and sand in
varying amounts and in impalpable subdivision. When carrying much
manganese ochers grade into umbers. They are either yellow, brown, or red.
The best reds are sometimes obtained by calcining the yellow varieties.
They are called burnt ochers. Others are obtained by calcining copperas or
as a residue from roasting pyrite. In general, the native yellows and
browns are varieties of limonite and the native reds are varieties of
hematite. One variety of red ocher is known as scarlet ocher. Their value
as pigments depends not only on the depth of color but also on the amount
of oil required as a vehicle. Syn:terra sienna
CCD, 2