Compared to low-grade metamorphic rocks,high-grade rocks ____________.
A) always contain more quartz and feldspar
B) are produced closer to the surface, high in the stratigraphic column
C) are produced at greater temperatures and pressures
D) are produced at cooler temperatures, but greater pressures

Question

Quizplus · Accepted Answer

High-grade metamorphic rocks are produced at greater temperatures and pressures than low-grade metamorphic rocks. The mineral assemblage and texture of high-grade rocks can vary greatly, but they typically contain minerals that are stable at high temperatures and pressures, such as garnet, staurolite, and kyanite. Low-grade rocks, on the other hand, typically form at shallower depths and lower temperatures and pressures, and may contain minerals like chlorite, muscovite, and biotite. The presence of quartz and feldspar is not necessarily indicative of the grade of metamorphism.

Compared to Low-Grade Metamorphic Rocks,high-Grade Rocks ____________