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An igneous rock consisting almost entirely of plagioclase feldspar, especially the labradorite variety.

[French anorthose, a kind of feldspar (Greek an-, not; see a-1 + Greek orthos, straight) + -ite.]

an·or′tho·sit′ic (-sĭt′ĭk) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


resembling or consisting of anorthosite
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
From this evidence and from looking at the highlands' topography and density, scientists concluded that the early Moon must have been nearly totally molten, covered by an ocean of magma in which low-density minerals floated to the top (forming an anorthositic crust) while denser, iron-rich minerals such as olivine sank to the bottom, ultimately becoming the mantle.
Alipour, "Synchronous activity of anorthositic and S-type granitic magmas in Chah-Dozdan batholith, Neyriz, Iran: evidence of Zircon SHRIMP and Monazite CHIME dating," Journal of Sciences, Islamic Republic of Iran, vol.
The view of the lunar landscape is described as "the world of rocks" The only two categories of the compositions of the crust found on the lunar surface are the highlands: Lighter and Anorthositic Surface, and the lunar maria: Darker and Basaltic Planes.
Lunar geology can be roughly broken down into two categories-the anorthositic highlands, rich in calcium and aluminum, and the basaltic "maria," giant impact basins filled with solidified lava flows that are abundant in iron and magnesium.
The drilling has intersected packages of both cumulate and intrusive style magnetite-ilmenite mineralisation intercalated with gabbroic and anorthositic country rock.
H.: 1977, Regional geobarometry in the contact aureoles of the anorthositic Nain Complex, Labrador, Jour.
The complex contains many individual mafic layered intrusions of tholeiitic affinity and structurally complex coeval anorthositic and felsic instrusions.