Igneous rocks with a two-stage intrusive-extrusive origin are recognized by a texture that is:
A) aphanitic.
B) porphyritic.
C) glassy.
D) phaneritic.
E) pyroclastic.

Question

Quizplus · Accepted Answer

Porphyritic texture in igneous rocks indicates a two-stage cooling process: slow cooling at depth (forming larger crystals) followed by rapid cooling at or near the surface (forming smaller crystals).

Igneous Rocks with a Two-Stage Intrusive-Extrusive Origin Are Recognized by a Texture