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 formed at greater temperatures and pressures compared to low-grade rocks. This results in the development of new minerals and the recrystallization of existing minerals, leading to changes in texture and mineralogy. The amount of quartz and feldspar present in the rock is not a distinguishing factor between low-grade and high-grade metamorphic rocks. The depth at which these rocks are formed is not necessarily related to their grade.

Consult the Figure Below