diabase

American  

[dahy-uh-beys] / ˈdaɪ əˌbeɪs /

noun

Petrology.

1. a fine-grained gabbro occurring as minor intrusions.

2. British. a dark igneous rock consisting essentially of augite and feldspar; an altered dolerite.

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diabase British  

/ ˈdaɪəˌbeɪs /

noun

1. an altered dolerite

2. another name for dolerite

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diabase Scientific  

/ dī′ə-bās′ /

1. 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.

2. Also called dolerite

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Other Word Forms

• diabasic adjective

Etymology

Origin of diabase

1810–20; < French, equivalent to dia- (error for di- two) + base base ¹

Example Sentences

The diabase of the Newark areas is almost exclusively confined to the red sandstone, and the dike at Leesburg cutting the limestone conglomerate is almost the only occurrence of that combination.

From History and Comprehensive Description of Loudoun County, Virginia by Head, James William

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

At Gympie, the auriferous area is confined to veins traversing a crystalline diorite, or within a certain limit of its boundary, marked by the presence of fossiliferous diabase tufas.

From Early Days in North Queensland by Palmer, Edward

The best-known locality is Fronolen near Tremadoc in North Wales, where crystals of the thin tabular habit occur with crystallized quartz, albite and anatase on the walls of crevices in diabase.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" by Various

In the eastern Thuringian Fichtelgebirge the upper division is represented by Clymenia limestone and Cypridina slates with Adorf limestone, diabase and Planschwitzer tuff in the lower part.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" by Various