Question

Peridotite, which is composed almost entirely of dark silicate minerals and is believed to make up much of Earth’s upper mantle, has a composition that is _____.

granitic

ultramafic

andesitic

basaltic

Description

Answer 1

ultramafic is the answer

Answer 2

The right option is; ultramafic

Peridotite is a dense, coarse-grained plutonic rock that is composed mostly of the minerals olivine and pyroxene. The composition of peridotite is ultramafic, as the rock has less than 45% silica and it has high magnesium content with significant amount of iron. Peridotite is economically valuable because it is a source rock for diamonds, and it is the major constituent of the upper part of the Earth's mantle.