xenolith

n.(geology) a piece of rock of different origin from the igneous rock in which it is embedded

1. The granite contained a xenolith of dark basalt, suggesting it came from a nearby volcanic region.
   花岗岩中含有一块深色玄武岩捕虏岩，这表明它来自附近的火山区。
2. Geologists examine xenoliths to determine the composition and properties of the Earth's mantle.
   地质学家研究捕虏岩以确定地幔的组成和性质。