basalt

basalt

1. a fine-grained dark basic igneous rock consisting of plagioclase feldspar, a pyroxene, and olivine: the most common volcanic rock and usually extrusive

2. a form of black unglazed pottery resembling basalt

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

basalt

A dense, dark gray volcanic rock, often full of small cavities, used as a building stone. See also: Stone

Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

basalt

[bə′sȯlt]

(petrology)

An aphanitic crystalline rock of volcanic origin, composed largely of plagioclase feldspar (labradorite or bytownite) and dark minerals such as pyroxene and olivine; the extrusive equivalent of gabbro.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

basalt

A dark, fine-grained, igneous rock used extensively for paving stones, but rarely for building stone.

McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Basalt

 

a magmatic rock. Basalt consists predominantly of plagioclase (labradorite); also present are pyroxenes, olivine, magnetite, sphene, apatite, and other minerals. The chemical composition of basalt is close to gabbro which is its analogue in depth. Almost completely crystalline basalts are called dolerites. Basalts which are greatly decomposed and altered by secondary processes are known as diabases and basalt-porphyry. Basalts which have erupted from large tectonic fissures over enormous areas of hundreds and thousands of square kilometers are called plateau-basalts or traps; after setting and cooling, their flows crack and form pillars separating closely adjoining pentagonal and hexagonal columns. Basalts are common among volcanic beds of all ages. Modern volcanoes also throw up basaltic lavas (on Kamchatka, the Hawaiian Islands, Iceland, New Zealand, and in many other regions). The origin of basaltic magma is one of the basic problems of geology. In the USSR, basalt is quarried in the Caucasus and the Ukraine (near Rovno). Basalt is a good building material and can be used for making gravel and block rubble, as well as for facing buildings. Basalt is durable and polishes well. For this reason, it has long been used for sculpture (ancient Egypt, Assyria, late Rome, Byzantium, and contemporary Armenia). It melts easily. Fused basalt is used in manufacturing acid-resistant chemical vessels, pipes, and strong current electric insulators.

REFERENCES

Levinson-Lessing, F. Iu. Petrografiia: Izbr. trudy, vol. 4. Moscow, 1955.
Zavaritskii, A. N. Izverzhennye gornye porody. Moscow, 1955.
Ioder, H. S., and C. E. Tilley. Proiskhozhdenie bazal’tovykh magm. Moscow, 1965. (Translated from English.)

V. P. PETROV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.