In geology, the term describes a piece of rock, mineral, or other foreign material that is trapped inside another rock or mineral. These enclosed fragments can provide significant insights into the history and formation of the host material. A classic example is a xenolith, a fragment of country rock included within an igneous intrusion. Another instance is a mineral crystal enclosed within a larger crystal of a different mineral.
The presence of these enclosed materials is invaluable for geochronology and petrogenesis studies. By analyzing the composition and age of the trapped substance, researchers can deduce information about the conditions and timing of the host’s formation. Examination can reveal the source regions of magmas, the pressures and temperatures experienced during metamorphism, and the sequence of events that shaped a particular geological setting. Their study has contributed substantially to the understanding of Earth’s dynamic processes throughout geological time.
