Pegmatites,which Often Occur in Dikes,are Unusual Among Shallow Intrusive Rocks

question 60

Multiple Choice

Pegmatites,which often occur in dikes,are unusual among shallow intrusive rocks in that they

• A) possess porphyritic texture.
• B) possess exceptionally coarse grains.
• C) are mineralogically identical to basalt.
• D) are glassy,cooling so rapidly that crystals do not have time to form.