Picrite


Also found in: Dictionary, Wikipedia.
Related to Picrite: Oceanite, ankaramite

picrite

[′pi‚krīt]
(petrology)
A medium- to fine-grained igneous rock composed chiefly of olivine, with smaller amounts of pyroxene, hornblende, and plagioclase felspar.

Picrite

 

an effusive rock composed of augite and olivine. Pi-crite also contains admixtures of hornblende, biotite, and or-thopyroxene and of various secondary minerals, including ilmenite, magnetite, and apatite. The olivine is often altered and replaced by serpentine, as well as by iddingsite, chlorite, and sometimes actinolite.

Picrites are holocrystalline. However, they sometimes contain a certain amount of glass inset with augite and olivine (picrite porphyry). The chemical composition of picrites is 38–41 percent SiO2, 5-10 percent Al2O3, and 20-29 percent MgO.

References in periodicals archive ?
'To our knowledge, the Luenha picrites are the first lava samples that could originate from the plume source that has been previously inferred from various geological and geophysical data on the Karoo province.
Pre-Qualification Criteria: Firms should either have past experience of supplying picrite plant or have experience of supplying similar explosive manufacturing plants with requisite and proven technology for manufacturing picrite.
However, the present exposures of picrites in the Deccan province are limited and their PGE contributions seem quite insufficient to approach the magnitude of the K-T Ir anolmaly (Sutherland, 1994).
Extraction is continuing on unmineralized gabbroic dolerite and picrite.
Tenders are invited for Tender For Bags Calico For M T Propellant And Picrite Bag Made Out Of Calico Cloth As Per C.F.A.
Tenders are invited for Plant For Manufacture Of Nitroguanidine (Picrite) Plant Of Capacity 1000 Mt / Annum Alongwith Associated Civil Works On Turn Key Basis As Per Ofi Specification
Tenders are invited for O.T.E.: Loading, Unloading & Shifting Of Picrite Filled Cardboard Boxes Of Net Wt.
The petrogenesis of Gorgona komatiites, picrites and basalts: new field, petrographic and geochemical constraints.
The geochemistry and petrogenesis of the Late-Cretaceous picrites and basalts of Curacao, Netherlands Antilles: A remnant of an oceanic plateau.
These rocks were first interpreted as komatiites (Alvarado et al., 1997) and then as picrites resulting of accumulation processes (Hauff et al., 2000) because the textures are porphyritic rather than spinifex.
These rocks contain more than 18 wt% MgO (Le Bas 2000) and are distinguished from other magnesium-rich rocks, such as picrites and meimechites, by having spinifex texture (characterized by spectacular arrays of subparallel or randomly-oriented skeletal, platy and bladed olivine crystals set in a glassy groundmass; Fig.
Edwards Basalt Formation--which is in turn disconformably overlain by the Widgiemooltha Komatiite Formation (olivine peridotites to picrites).