a. Any ancient land; specif. an extensive area (such as the Canadian
shield) of ancient crystalline rocks reduced to low relief by
long-continued erosion and from which the materials of later sedimentary
deposits were derived. AGI
b. A region of older land, behind a coastal plain, that supplied the
material of which the coastal-plain strata were formed. AGI
c. A term proposed by Maxson and Anderson (1935) for the land surface of
the old-age stage of the cycle of erosion, characterized by subdued
relief. AGI
A thick sequence of nonmarine, predominantly red sedimentary rocks,
chiefly sandstones, conglomerates, and shales, representing the Devonian
System in parts of Great Britain and elsewhere in northwestern Europe.
AGI
Scrap derived from consumer goods that have outlived their usefulness in
the economy; it includes discarded white goods, automobiles, electrical
equipment, machinery, etc.
Silver made to appear old by the application of graphite and grease.
Scot. Old or abandoned workings. Fay
Mine working that has been abandoned, allowed to collapse, and perhaps
sealed off. Unless proper safeguards are taken, old workings can be a
source of danger to workings in production particularly if they are
waterlogged and their plan position is uncertain.
See also:inrush of water
Leaf-shaped masses of stromeyerite (or other minerals) in a matrix of
chalcocite (or other mineral). AGI
Ch3 (CH2 ),CH:CH(CH2 )7 COOH ; a
mono-unsaturated fatty acid used in ore flotation; insoluble in water; and
soluble in alcohol, ether, and in most other organic solvents.
CCD, 2
See:hematite
See:hematite
An epoch of the early Tertiary Period, after the Eocene and before the
Miocene; also, the corresponding worldwide series of rocks. It is
considered to be a period when the Tertiary is designated as an era.
AGI
A triclinic mineral, (Na,Ca)[(Si,Al)AlSi2 O8 ] ; plagioclase
series of the feldspar group; has NaSi (albite) 10 to 30 mol % and CaAl
(anorthite) 90 to 70 mol %; pseudomonoclinic with prismatic cleavage and
characteristic polysynthetic twinning commonly visible on cleavage traces;
white; may be chatoyant; a common rock-forming mineral in igneous and
metamorphic rocks of intermediate to high silica content; forms the entire
mass in some anorthosites; less commonly a vein mineral.
A former name for manganoan siderite, (Fe,Mn)CO3 .
A meteorite containing a small amount of metallic iron. AGI
Peat poorly supplied with nutrients. Tomkeieff
An orthorhombic mineral, Cu2 AsO4 (OH) ; adamantine to
vitreous; a secondary mineral in copper deposits.
A continuous-type filter made in the form of a cylindrical drum with
filter cloth stretched over the convex surface of the drum. The drum
rotates slowly about a horizontal axis, and the lower part is immersed in
a tank containing the pulp to be filtered. Arrangement of pressure and
suction pipes on the interior of the drum permits the application of
suction to the filtering surface. As the filter passes through the tank,
it picks up a layer of solid material and emerges carrying a layer of
filter cake. Syn:continuous filter
A mineral group including fayalite, Fe2 SiO4 ; forsterite,
Mg2 SiO4 ; liebenbergite, (Ni,Mg)2 SiO4 ; and
tephroite, Mn2 SiO4 ; orthorhombic; olive green, grayish
green, brown, or black; members intermediate in the forsterite-fayalite
crystal solution series are common rock-forming minerals in gabbros,
basalts, peridotites, and dunites; alters hydrothermally to serpentine.
Fayalite occurs in some granites and syenites, forsterite in thermally
metamorphosed dolomites, and tephroite in iron manganese ore deposits and
their associated skarns. Syn:peridot; chrysolite; olivinoid.
See:dunite
a. In the International Union of Geological Sciences classification,
Syn:dunite
b. An olivine-rich ore-bearing igneous rock that also contains other
pyroxenes and/or amphiboles. Syn:leucochalcite
An olivinelike substance found in meteorites. See also:olivine
Standard, 2