Naturally occurring molten rock, generated within the Earth and capable of
intrusion and extrusion, from which igneous rocks are derived through
solidification and related processes. It may or may not contain suspended
solids (such as crystals and rock fragments) and/or gas phases. Adj:
magmatic. AGI
Of, pertaining to, or derived from magma. See also:igneous
See:assimilation
The swelling up by differential heating of magma; e.g., by local
concentrations of radioactive matter. Schieferdecker
A process of re-solution in which an early formed phase, such a quartz
phenocryst, later becomes corroded or embayed as the result of some change
in the conditions affecting the solubility of the phase; sometimes
corrosion rims result. Syn:corrosion
See:igneous cycle
The process by which more than one rock type is derived from a parent
magma. CF:assimilation
magmatic disseminated ore deposit
See:assimilation
Straight magmatic mineral (ore) deposit, the formation of which has often
been ascribed to injection into the older country rock of liquefied
crystal differentiates, of residual liquid segregations, or of immiscible
liquid separations and accumulations. An older term.
Schieferdecker
An ore deposit formed by magmatic segregation, generally in mafic rocks
and layered intrusions, as crystals of metallic oxides or from an
immiscible sulfide liquid. Syn:magmatic deposit
Concentration of crystals of a particular mineral (or minerals) in certain
parts of a magma during its cooling and crystallization. Some ore deposits
(i.e., magmatic ore deposits) are formed in this way.
See also:differentiation
A process of magmatic emplacement or intrusion that involves detaching and
engulfing pieces of the country rock. The engulfed material presumably
sinks downward and/or is assimilated. See also:piecemeal stoping
AGI
Water contained in or expelled from magma. CF:juvenile water
AGI
One who believes that much granite is a primary igneous rock produced by
differentiation from basaltic magma. CF:transformist
Trademark for iron oxide heavy media systems for the purification of coal,
sand, gravel, and other similar materials. CCD, 2
A widely used medium for magnetic recording. It consists of a circular
platter of magnetically coated plastic material that rotates on a
turntable in the same way as a phonograph record. The magnetic channels,
each in contact with a fixed head aligned along a radius from the center,
are on concentric circular bands extending inward from the outer edge of
the disk. Dobrin
Magnesium oxide, MgO. A constituent of lime made from dolomitic limestone.
Barger; AGI; Mersereau, 2
See:pickeringite
Hydrated magnesium carbonate containing about 15% asbestos, used for heat
insulation. Also referred to as 85% magnesia. Osborne