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[zen-l-ith] /ˈzɛn l ɪθ/
noun, Petrography
a rock fragment foreign to the igneous rock in which it is embedded.
Also called inclusion.
1900-05; xeno- + -lith
Related forms
xenolithic, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for xenolith
  • Each xenolith studied tells a slightly different story.
  • Any rock material carried by lava but not genetically related to it can be called a xenolith.
  • Faint layering can be seen in granite between hammerhead and xenolith.
British Dictionary definitions for xenolith


a fragment of rock differing in origin, composition, structure, etc, from the igneous rock enclosing it
Derived Forms
xenolithic, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for xenolith

1894, from xeno- "foreign, strange" + -lith "stone."

Online Etymology Dictionary, © 2010 Douglas Harper
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xenolith in Science
  (zěn'ə-lĭth', zē'nə-)   
A rock fragment foreign to the igneous mass in which it occurs. Xenoliths usually become incorporated into a cooling magma body when pieces of the rock into which the magma was injected break off and fall into it. Compare xenocryst.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for xenolith

rock fragment within an intrusive igneous body that is unrelated to the igneous body itself. Xenoliths, which represent pieces of older rock incorporated into the magma while it was still fluid, may be located near their original positions of detachment or may have settled deep into the intrusion, if their density is greater. Xenoliths can be contrasted with autoliths, or cognate xenoliths, which are pieces of older rock within the intrusion that are genetically related to the intrusion itself. The general term for all such incorporated bodies is inclusions. Xenoliths are usually reconstituted through the processes of contact metamorphism, in which heat and fluids cause mineralogic and chemical changes in the parent rock of the xenolith; a study of these changes can give information on the temperature and composition of the magmatic body

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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