Question

Earth's layers formed as result of differentiation. During differentiation, elements and compounds formed varied layers of minerals. Minerals with low densities tend to crystalize from magma at cooler temperatures; minerals with greater densities crystalize at higher temperatures. Think about the zones or layers of the Earth. We would expect the rocks in the upper mantle of the lithosphere to have a high proportion of
A finely crystallized, dense minerals.
B heavier, denser minerals such as galena.
C less dense minerals that form rocks such as granite.
D minerals that contain heavy metals such as iron and nickel.

Answer 1

D

The upper mantle is composed of dense, mafic/ultramafic minerals (e.g., olivine and pyroxene) that are rich in iron and magnesium. These higher-temperature, higher-density minerals are concentrated in the mantle. (Choices A and C describe felsic/quick-cooled or crustal materials; B names galena, a lead sulfide not characteristic of mantle rocks.)