Shale is metamorphosed into three rock types: 1) a banded gneissic rock; 2) a rock with small mica crystals with a shiny aspect; 3) a very shiny rock with large mica crystals; and 4) a dull slate with cleavage. Which of the following lists these rocks in order of increasing metamorphic grade?
A) 1, 2, 3, 4
B) 4, 3, 2, 1
C) 2, 3, 4, 1
D) 4, 2, 3, 1
E) 3, 2, 4, 1

Question

Quizplus · Accepted Answer

The correct order from lowest to highest metamorphic grade is slate (a dull slate with cleavage), phyllite (a rock with small mica crystals with a shiny aspect), schist (a very shiny rock with large mica crystals), and gneiss (a banded gneissic rock). This sequence reflects the increasing degree of metamorphism and the changes in mineral size and banding that occur as the grade increases.

Shale Is Metamorphosed into Three Rock Types: 1) a Banded