Question

Approximately how much of the Earth's crust is composed of Pyroxene?

• A. More than 50%
• B. Exactly 25%
• C. 10%
• D. Less than 1%

Answer 1

Answer:

C. 10%

Pyroxenes

Pyroxenes are a group of inosilicate minerals, meaning their silicate tetrahedra are arranged in single chains. They form an important component of the Earth's crust, particularly in mafic and ultramafic igneous rocks.

Key Properties and Occurrence:

• Pyroxenes are typically dark-colored minerals, ranging from green to brown and black.

• Their crystal structure features two distinct cleavage directions that intersect at approximately 87 and 93 degrees, a characteristic feature used in mineral identification.

• Common examples of pyroxenes include augite, enstatite, and diopside.

Geological Importance:

• Pyroxenes play a crucial role in the formation of various rock types such as basalt, gabbro, and andesite.

• They are also found in metamorphic rocks formed under high temperatures and pressures.

• The presence and type of pyroxenes in a rock can provide valuable insights into the origin, cooling history, and geological processes that shaped the rock.

• Minerals belonging to the pyroxene group are estimated to constitute approximately 10% of the Earth's crust by weight.