What are mantle xenoliths?

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. Mantle Xenolith (Peridotite)

Where are xenoliths found?

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.

Where do xenoliths typically come from?

Xenoliths most often occur in igneous rocks. For those of you who are a little rusty on Geology 101, igneous rocks are rocks which form by the cooling and solidification of molten material– either magma or lava. As magma or lava migrates and cools to form igneous rock, it may pick up inclusions of foreign rock.

How old are xenoliths?

Many western U.S. xenoliths have been dated at 1.7 Ga.

Are all xenoliths the same?

They have a different color and density than the surrounding igneous rock. Xenoliths can be as small as a grain of sand or as large as a football, and as long as several meters. Xenoliths and xenocrysts are affected by temperature. A xenolith may lose its unique qualities if it melts into the surrounding magma.

Which is older the granite or xenoliths?

We can safely say that granite has to be older. It was already solid rock when it was intruded by mafic lamprophyric magma that scraped some pieces off of granitic rock and embedded them within the solidifying magma. Inclusions of foreign rocks that are found in igneous rocks are named xenoliths.

Is granite older than basalt?

Basalt can form in a few days to months, whereas granite plutons can take millions of years to cool and harden. Basalt is more common in oceanic crust while granite is more common in continental crust.