Which of the following lists the rocks in the order of increasing grain size and increasing grade for regionally metamorphosed mud rocks?
A)phyllite, slate, schist
B)schist, slate, phyllite
C)slate, phyllite, schist
D)slate, schist, phyllite

Question

Quizplus · Accepted Answer

Regionally metamorphosed mud rocks begin as fine-grained sedimentary rocks, such as shale or mudstone. As they undergo metamorphism, they develop foliation and recrystallize, making the grain size larger. Slate has the smallest grain size, followed by phyllite and then schist. Therefore, the correct order is slate, phyllite, schist, making choice C the correct answer.

Which of the Following Lists the Rocks in the Order