A porphyritic texture where large crystals are embedded in a matrix of small crystal may form when_________ .
A) climate change causes crystals to cool at different rates
B) crystals of different compositions grow to different sizes
C) a magma that has partially crystallized slowly moves to a different location where it then cools rapidly
D) crystals of different compositions cool at different rates

Question

Quizplus · Accepted Answer

A porphyritic texture forms when magma cools in two different environments: initially, it cools slowly, allowing large crystals to form, and then it moves to a location where it cools rapidly, resulting in a matrix of smaller crystals. This is described in option C.

A Porphyritic Texture Where Large Crystals Are Embedded in a Matrix