Lamprophyre


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Related to Lamprophyre: Ijolite

lamprophyre

[′lam·prə‚fī·ər]
(petrology)
Any of a group of igneous rocks characterized by a porphyritic texture in which abundant, large crystals of dark-colored minerals appear set in a not visibly crystalline matrix.

Lamprophyre

 

melanocratic igneous dike rock that differs from the corresponding igneous rocks to which it is genetically related by its sharply increased content of dark minerals (usually at least 30 percent of the rock). The color of lamprophyre varies from dark gray to black. Its constituents include feldspar (sometimes feldspathoid) and dark minerals (biotite, amphibole, pyroxene, and sometimes olivine). In the porphyritic varieties of lamprophyre the phenocrysts are usually represented by dark minerals—this is called lamprophyric texture. There are calcalkalic lamprophyres (spessartite, kersantite) and alkalic lamprophyres (camptonite, alnöite). Lamprophyres sometimes grade into porphyrites.

References in periodicals archive ?
They are petrographicaly identified as dolerites and lamprophyres. The dolerites are texturally basaltic, doleritic and gabbroic and are altered compare to lamprophyres.
Guo et al., "Mechanical property-variation under dynamic uniaxial compression and micro-mechanism of lamprophyre in saturated state," Journal of the China Coal Society, vol.
Hu, "The logging interpretation for Lamprophyre," ACTA Petrolei Sinica, vol.
In field measurement, before forced caving measures such as hydraulic fracturing and presplitting blasting, the first breaking span of the 20-meter-thick lamprophyre can reach about 110 m, and the periodic breaking span of the 20-meter-thick lamprophyre can reach between 65 m and 75 m.
The rock in the second vent is a quartz porphyry which also contains topaz, and there is a long contact zone into which a lamprophyre was intruded.
The Discover Abitibi Initiative (DAI) recently released the results of a lamprophyre study, designed to determine the diamond bearing potential of lamprophyres in Timmins, Kirkland Lake and Timiskaming areas.
In the Montreal area such rocks are mostly alkaline syenite, monzonite, basanite or alkali olivine basalt, and lamprophyre, especially camptonite (Hodgson, 1968; Eby, 1985).
0.025-0.015 Ga: An important intraplate event is the widespread Behm Canal event [#29a] of the Cordillera, which is also known as the Tertiary Lamprophyre Province.
The diatreme consists of a large mass of breccia intruded by bodies of phonolite, plagioclase phonolite (historically called latite phonolite), tephriphonolite (historically called syenite), and lamprophyre (historically called alkali basalt) (Kelley, 1996; Pontius, 1996).
Cabo Mining out of Vancouver has struck an interesting twist in Lorraine Township south of Cobalt with the discovery of diamonds in lamprophyre and associated heterolithic breccias, similar to diamond discoveries made in Wawa, he says.
There will also be lamprophyre sampling, kimberlite (diamond) geochemistry, a seismic profile and regional gravity surveys.