a. A sedimentary layer deposited or presumed to have been deposited during
the course of a year; e.g., a glacial varve. AGI
b. A dark band (in a salt stock) of formerly disseminated anhydrite
crystals that accumulated upon being freed by solution of the enclosing
salt. AGI
The annual value of a property is the estimated annual surplus of revenue
over expenditure in process of liquidating the mineral reserves. In the
usual case, that of a property owned by a company, it is the dividend
estimated maintainable annually over the whole computed life, the regular
distribution of mining profit. Truscott
A ring bearing that carries the radial load of a shaft. If a ball bearing,
the balls are held in a race and run on a hard band around the shaft.
Petroleum Age
A drainage pattern in which streams follow a roughly circular or
concentric path along a belt of weak rock, resembling in plan a ringlike
pattern. It is best displayed by streams draining a maturely dissected
structural dome or basin where erosion has exposed rimming sedimentary
strata of greatly varying degrees of hardness, as in the Red Valley, which
nearly encircles the domal structure of the Black Hills, SD. AGI
A kiln having compartments. Standard, 2
a. The positive pole of an electrolytic cell. Webster 3rd
b. The terminal at which current enters a primary cell or storage battery;
it is positive with respect to the device and negative with respect to the
external circuit. McGraw-Hill, 1
c. The electropositive pole. AGI
d. The electrode at which electrons leave a device to enter the external
circuit; opposite of cathode. See also:electrode
e. The negative terminal of a primary cell or of a storage battery that is
delivering current. Webster 3rd
In an electrolytic cell, the enclosure formed by a diaphragm around the
anodes. ASM, 1
Specially shaped copper slabs used as anodes in electrolytic refinement,
and resulting from the refinement of blister copper in a reverberatory
furnace. ASM, 1
The effect produced by polarization of an anode in the electrolysis of
fused salts. It is characterized by a sudden increase in voltage and a
corresponding decrease in amperage due to the anode being virtually
separated from the electrolyte by a gas film. ASM, 1
A copper- or nickel-refining furnace, in which blister copper or impure
nickel is refined.
Metals used for electroplating. They are as pure as commercially possible,
uniform in texture and composition, and have the skin removed by
machining. In addition to pure single metals, various alloys are produced
in anode form, such as Platers' brass and Spekwite, the latter yielding a
white plate harder than nickel. Brady, 2
A deposit of insoluble residue formed from the dissolution of the anode in
commercial electrolysis. Sometimes called anode slime. In copper refining,
this slime contains the precious metals that are recovered from it.
ASM, 1; CTD
Remnants of anode copper retrieved from electrolytic refining of the
metal. Pryor, 3
Metals or metal compounds left at, or falling from, the anode during
electrolytic refining. The plural form is often used.
In the electrical self-potential method of geophysical prospecting, if the
chemical composition of the soil or subsoil is such as to give electrical
polarization, the zone of electropositive potential is the anodic zone.
AGI
a. A departure from the expected or normal. AGI
b. The difference between an observed value and the corresponding computed
value. AGI
c. A geological feature, esp. in the subsurface, distinguished by
geological, geophysical, or geochemical means, which is different from the
general surroundings and is often of potential economic value; e.g., a
magnetic anomaly. AGI
d. Any deviation from conformity or regularity. A distinctive local
feature in a geophysical, geological, or geochemical survey over a larger
area. An area or a restricted portion of a geophysical survey, such as a
magnetic survey or a gravity survey, that differs from the rest of the
survey in general. The anomaly might be associated with petroleum, natural
gas, or mineral deposits, or provide a key to interpreting the underlying
geologic structure. Drilling for economic mineral deposits might be
conducted in the area of a geophysical anomaly. In seismic usage, anomaly
is generally synonymous with subsurface structure or material properties,
but it is also used for spurious or unexplainable seismic events or for
local deviations of observed signals which cannot be conclusively
attributed to a unique cause. See also:hydrochemical anomaly
AGI
e. A gravity anomaly is the difference between the theoretical calculated
gravity and the observed terrestrial gravity. In comparing any set of
observed data with a computed theoretical curve, the difference of an
observed value and the corresponding computed value, or the observed minus
the computed value. Excess observed gravity is a positive anomaly, and a
deficiency is a negative anomaly. See also:Bouguer anomaly;
free-air anomaly; isostatic anomaly. AGI
f. A crystallographic anomaly is the lack of agreement between the
apparent external symmetry of a crystal and the observed optical
properties. Schieferdecker
g. Any departure from the normal magnetic field of the Earth is a magnetic
anomaly. It may be a high or a low, subcircular, ridgelike or valleylike,
or linear and dikelike. AGI
Obsolete syn. for a triclinic crystal system. See also:triclinic
a. A triclinic mineral, 4[CaAl2 Si2 O8 ] ;
plagioclase series of the feldspar group, with up to 10 mol % NaSi
replacing CaAl; white to gray; in ultramafic intrusive igneous bodies and
skarns. Syn:calcium feldspar; calcium plagioclase; calciclase;
lepolite.
b. A pure calcium end member of the plagioclase series.
A triclinic mineral, 4[(Na,K)AlSi3 O8 ] ; feldspar group;
occurs in tabular crystals with prismatic cleavage; colorless or white; in
felsic volcanic rocks. CF:orthoclase
A plutonic rock composed almost entirely of plagioclase, usually
labradorite. It is a monomineralic equivalent of gabbro but lacks
monoclinic pyroxene. CF:andesinite
Introduction of, or replacement by, anorthosite. AGI