diabase
Americannoun
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a fine-grained gabbro occurring as minor intrusions.
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British. a dark igneous rock consisting essentially of augite and feldspar; an altered dolerite.
noun
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an altered dolerite
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another name for dolerite
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A dark-gray to black, medium-grained igneous rock consisting mainly of labradorite and pyroxene. Diabase is compositionally similar to andesite, but has coarser grains. It is commonly found in sills and dikes.
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Also called dolerite
Other Word Forms
- diabasic adjective
Etymology
Origin of diabase
1810–20; < French, equivalent to dia- (error for di- two) + base base 1
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The minerals of diabase are the same as those of dolerite, viz. olivine, augite, and plagioclase felspar, with subordinate quantities of hornblende, biotite, iron oxides and apatite.
From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" by Various
In the cores of the arches of Arenig cherts there are diabase lavas, tuffs and agglomerates which are typically represented on Bail Hill E. of Kirkconnel.
From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" by Various
When these rocks become fine-grained they pass gradually into ophitic diabase and dolerite; only very rarely does olivine enclose 378 felspar in this way.
From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" by Various
It is found in the greenstone and hornblende-schists of Batallack Head near St Just in Cornwall, and in diabase in the Harz; and small ones in Maine and in Northampton county, Pennsylvania, U.S.A.
From Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" by Various
The igneous rocks are commonly acid intrusives of a granite or porphyry type, less commonly intrusives of gabbro and diabase and surface lavas of rhyolite and basalt.
From The Economic Aspect of Geology by Leith, C. K. (Charles Kenneth)
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
