A crystal in an igneous rock which is not derived from the original magma.
- ‘The xenocrysts provide evidence that earlier Neoproterozoic rocks were present in the region and that locally rocks date back to 1929 Ma.’
- ‘This could represent a xenocryst derived from Archaean basement rocks of the region.’
- ‘Xenoliths, which are pieces of wall rock, or xenocrysts, which are single mineral grains that originate from xenoliths, can commonly be recognized at outcrops of magmatic rocks.’
- ‘We interpret these grains as xenocrysts from an older source terrain from which the granitic protolith of sample MS 3 may have been derived by anatectic melting.’
- ‘Again, the lack of zircon xenocrysts in this sample does not allow discrimination between these alternatives.’
Late 19th century: from xeno- ‘foreign’ + crystal.
We take a look at several popular, though confusing, punctuation marks.