A dacite is the volcanic equivalent to which plutonic rock?

• A. Granodiorite
• B. Granite
• C. Diorite
• D. Gabbro

Answer: (A)

Dacite and granodiorite share the same silica-rich, felsic chemistry, but one is fine-grained because it cooled quickly at the surface while the other is coarse-grained from slow cooling underground. The mineral mix lines up well: both contain quartz and plagioclase as major minerals, with granodiorite also having notable K-feldspar in addition to plagioclase. This combination mirrors what you’d expect in dacite, making granodiorite the plutonic counterpart to dacite.

Diorite would pair with andesite, granite with rhyolite, and gabbro with basalt, so those options don’t fit the same silica- and mineral-content relationship as dacite and granodiorite.