gabbro

Definitions

  • WordNet 3.6
    • n gabbro one of a family of granular intrusive rocks
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Webster's Revised Unabridged Dictionary
    • n Gabbro (Geol) A name originally given by the Italians to a kind of serpentine, later to the rock called euphotide, and now generally used for a coarsely crystalline, igneous rock consisting of lamellar pyroxene (diallage) and labradorite, with sometimes chrysolite (olivine gabbro).
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Century Dictionary and Cyclopedia
    • n gabbro A rock of varied lithological character, essentially, according to the present general acceptation of the name among lithologists, a crystalline-granular aggregate of plagioclase and diallage, with which often occur magnetite (or menachanite) and apatite. Often the diallage is associated with a rhombic pyroxene (bronzite or hypersthene, two closely allied members of the augite or pyroxene family), and when this predominates the rock passes into what is called norite. Olivin is also frequently present, and the predominance of this mineral gives rise to combinations to which the names olivin-gabbro and olivin-norite have been given. The original gabbro of Von Buch, now called saussurite-gabbro, is one of the many alterative forms of gabbro proper, which is perhaps the most perplexing of all rocks in respect to the manifold nature of the alterations it is liable to undergo. In regard to the nomenclature of many of these there is not much present unity among lithologists. Gabbro rosso (It., red gabbro), a rock occurring at the junction of the serpentine and the macigno (a micaceous sandstone) of Tuscany, is an altered sedimentary formation very variable in texture and composition. Gabbro verde (It., green gabbro), or gabbro simply, as it is sometimes called, is serpentine. The gabbro verde of Tuscany does not contain diallage; the rock called gabbro in Corsica, on the other hand, has crystals of diallage disseminated through the serpentine. Verde di Corsica (It., Corsica green), a variety of gabbro now called by Italians grani-tone and eufotide (euphotide), is the beautiful green stone extensively employed in the interior decorations of the Medicean chapel in Florence. It is a crystalline aggregate of saussurite and smaragdite (a grass-green variety of hornblende). See hypersthenite.
    • n gabbro It is proposed, in the field classification of igneous rocks in connection with the quantitative system of classification (1902), to use the term gabbro for all granular igneous rocks with dominant pyroxene and subordinate feldspar of any kind, with or without hornblende and mica. Such rocks would include the less feldspathic gabbros and norites, and some diorites. See rock.
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Chambers's Twentieth Century Dictionary
    • n Gabbro gab′ro a rock composed of feldspar and diallage—also Euphotide
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Etymology

Webster's Revised Unabridged Dictionary
It
Chambers's Twentieth Century Dictionary
It.

Usage

In literature:

These volcanic materials are pierced by serpentine, gabbro and granite.
"Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1" by Various
It may stop far below the surface and cool slowly, forming coarsely crystallized rocks of the granite and gabbro types.
"The Economic Aspect of Geology" by C. K. Leith
Lithologically they are crystalline schists, together with granite, diorite, gabbro and other igneous rocks.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 2" by Various
Peridotite and gabbro form much of the eastern peninsula (Banggai).
"Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5" by Various
The acid and basic plutonic rocks (gabbros and granophyres) of Tertiary time occur in Ardnamurchan.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5" by Various
Euphotide, Gabbro, and some Ophiolites.
"A Manual of Elementary Geology" by Charles Lyell
Diabases, gabbros, serpentines, soda-potash granites, &c., are found in the Eocene of the central and northern Apennines.
"Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6" by Various
Five yards away, perhaps, a great mass of purple gabbro hung over a patch of nearly snowless moss.
"Marriage" by H. G. Wells
Gabbro, Penig, Saxony; III.
"Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4" by Various
Their essential minerals are pyroxene, plagioclase and garnet: chemically they resemble the gabbros.
"Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3" by Various
The gneisses appear to be due in many cases to the crushing and shearing of deep-seated igneous rocks, such as granite and gabbro.
"The Elements of Geology" by William Harmon Norton
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