What does xenolith mean?
A xenolith is a fragment of rock physically enclosed within a different, usually igneous, rock mass. The term is especially important in geology because xenoliths can preserve evidence about the origin, history, and ascent of magma: granite may contain pieces of the surrounding country rock, while volcanic rock may carry fragments upward from depth. Geologists use the word as a precise technical label rather than a synonym for every inclusion, because the enclosed material is foreign to its host. In descriptions of granite, basalt, and other igneous bodies, xenoliths may be characterized by their composition, such as “mafic xenolith.” A xenolith is a useful reminder that igneous rock can incorporate and preserve material from its surroundings rather than forming as a completely uniform substance.
nounA xenolith is a fragment of rock enclosed within a larger mass of different rock, especially igneous rock. It is a specific type of inclusion whose material is foreign to the surrounding host rock.
- A fragment of foreign rock enclosed within a larger, usually igneous, rock mass.
"The quarry exposed a dark xenolith embedded in the pale granite."
"Geologists studied the xenoliths trapped in the granite to understand the composition of the surrounding terrain."
"A block containing a conspicuous xenolith was displayed in the museum's geological collection."
The standard plural of xenolith.
"Numerous xenoliths occur along the margins of the granite intrusion."
A xenolith is a geological stowaway: a piece of foreign rock carried by magma and locked inside a new rock mass.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of xenolith
The term was formed in the nineteenth century from Greek xénos, meaning “foreign” or “stranger,” and lithos, meaning “stone.” The same Greek element underlies words such as xenobiotic, xenogeneic, xenophile, and xenon, although those words developed through separate formations.
Related word forms
How xenolith is actually used
This is primarily a specialist geological term. It should not be used for an inclusion of any kind unless the enclosed material is demonstrably foreign to its host rock.
Easily confused with xenolith
An endolith is a rock fragment enclosed within another rock, whereas a xenolith is specifically an enclosed fragment of material foreign to its host.