Pumice and scoria are examples of glassy igneous rocks that contain a lot of ______.
A) vesicles
B) phenocrysts
C) volatiles
D) xenoliths

Question

Pumice and scoria are examples of glassy igneous rocks that contain a lot of ______. 
A) vesicles 
B) phenocrysts 
C) volatiles 
D) xenoliths

Quizplus · Accepted Answer

Pumice and scoria are both formed from rapidly cooling lava with a high gas content. As the lava rapidly cools, the gas is unable to escape and becomes trapped, creating voids or vesicles in the resulting rock. Therefore, option A (vesicles) is the best choice.

Pumice and Scoria Are Examples of Glassy Igneous Rocks That