GENERAL GEOLOGY

Detailed explanation-1: -Sometimes magma carries fragments of unmelted rock, called xenoliths, within it. Melting of xenoliths can also alter the composition of magma, as can re-melting of crystals that have settled out of the magma.

Detailed explanation-2: -Xenoliths can be a piece of rock trapped in a piece of sedimentary rock, but this is rare. Xenoliths have also been found in meteorites, or rocks from outer space that have crashed into Earth. The xenoliths in meteorites were formed from collisions with other objects outside the Earths atmosphere.

Detailed explanation-3: -Mantle xenoliths are rocks from the Earth’s upper mantle that became enveloped in magma when it erupted from deep underground. In the Oki Islands, mantle xenoliths are found within basalt lava, which erupted 4 million to 400, 000 years ago. The Earth’s interior can be roughly divided into three parts.

Detailed explanation-4: -« Back to Glossary Index. A piece of foreign rock that has been incorporated into a magma body. This can be a different type of magma, or a mantle xenolith, a rock from the mantle brought up near the surface.

Detailed explanation-5: -A xenocryst is an individual foreign crystal included within an igneous body. Examples of xenocrysts are quartz crystals in a silica-deficient lava and diamonds within kimberlite diatremes.