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

Question

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

Quizplus · Accepted Answer

High-grade metamorphic rocks are produced at greater temperatures and pressures than low-grade metamorphic rocks. This is because they have undergone more intense metamorphism and have been subjected to more extreme conditions of heat and pressure. The mineral composition of the rocks may vary depending on the type of rock and the specific conditions of metamorphism, but it is not necessarily the case that high-grade rocks always contain more quartz and feldspar than low-grade rocks or that they are produced closer to the surface. Additionally, high-grade metamorphic rocks are not produced at cooler temperatures but greater pressures, as stated in choice D.

Consult the Figure Below