A term proposed by Pettijohn (1957) for a conglomerate that is not a
product of normal aqueous flow, but is deposited by such agents as
subaqueous turbidity slides and glacier ice; it contains more matrix than
gravel-sized fragments (pebbles may form less than 10% of the rock).
Examples include tillites, pebbly mudstones, and relatively structureless
clay or shale bodies in which pebbles or cobbles are randomly distributed.
Syn:conglomerate mudstone
A trigonal mineral, Fe3+2 (SO4 )3 .9H (sub
2) O ; dimorphous with coquimbite; pale violet; astringent tasting;
secondary; in oxidized iron sulfide deposits.
A triclinic mineral, Zn2 (AsO4 )(OH) ; rare; dimorphous with
adamite and isomorphous with tarbuttite; transparent; vitreous; pale
yellow; forms sheaflike aggregates and striated equant crystals; at the
Ojuela Mine, Durango, Mexico.
See:oil shale
A characteristic association or occurrence of minerals or mineral
assemblages in ore deposits, connoting contemporaneous formation.
CF:mineral sequence
a. Pertaining to paragenesis. AGI
b. Pertaining to the genetic relations of sediments in laterally
continuous and equivalent facies. AGI
In petrology, a gneiss formed by the metamorphism of a sedimentary rock.
CF:orthogneiss
Trade name for a nonrotating rope of 12 by 6 over 3 by 24 strand
construction. Hammond
A monoclinic mineral, NaAl2 (AlSi3 )O10 (OH)2;
mica group; pseudohexagonal with basal cleavage; forms fine-grained,
massive, scaly aggregates; occurs in metamorphic rocks and in soils; not
common as it is incompatible with potassium feldspar (albite plus
muscovite is more stable); rarely identified because of its similarity to
muscovite. Syn:soda mica
A variety of schist in which paragonite supplants muscovite or biotite.
A trigonal mineral, Bi2 (Se,S)3 ; paramorphous after
orthorhombic guanajuatite.
A mineral trimorphous with monoclinic hilgardite and triclinic hilgardite.
See also:hilgardite
A colorless hydrous zinc phosphate, Zn3 (PO4 )2 .4H
2 O , triclinic. Minute tabular or prismatic crystals; fan-shaped
aggregates. From Broken Hill, Northern Rhodesia; Salmo, BC.
English
An orthorhombic mineral, Pb4 FeSb6 S14 ; dimorphous
with jamesonite; metallic; black; distinguished by its X-ray pattern.
A monoclinic mineral, PbCl(OH); dimorphous with laurionite; soft; forms
white pseudo-orthorhombic prismatic crystals; a secondary mineral in lead
deposits.
Said of deposits laid down on the landward side of a coast, in shallow
fresh water subject to marine invasions. Thus, marine and nonmarine
sediments are interbedded; as exemplified in the lower part of the Coal
Measures, the nonmarine (paralic) predominate, with relatively thin marine
bands. CF:limnic
A coal basin that originated near the sea--as opposed to a limnic coal
basin. AGI
a. In survey work, incorrect reading of a graduation on an instrument if
the observer's eye is not truly normal to the graduated plate.
Pryor, 3
b. The change in bearing or apparent position of an object produced by a
change in the observer's position. NCB
c. The apparent displacement, or change in position, of the crosshairs of
a focusing telescope with reference to the image of an object, as the eye
is moved from side to side, when the focus of the eyepiece or objective is
imperfect. Seelye, 2
An electric blasting circuit in which the leg wires of each detonator are
connected across the firing line directly or in parallel through bus
wires. Syn:series-in-parallel circuit
Atlas
A method of connecting together a number of detonators that are to be
fired electrically in one blast. The electric detonators are connected to
two common points. Each detonator offers a path for the electric current,
independent of all the other detonators in the circuit, and therefore
calls for a higher amperage than a series circuit in which there is but
one path. Nelson
Group of parallel holes, not all charged with explosive, that creates the
initial cavity to which the loaded holes break in blasting a development
round. Pryor, 3