A roughly circular mound-shaped bulge that builds up from the slow eruption of viscous felsic lava from a volcano is called:

Correct option is B

Lava domes form from the slow eruption of highly viscous felsic lava, resulting in a mound-shaped bulge near the volcanic vent.

Information Booster

1. Lava domes are rich in silica, making the lava thick and slow-moving.
2. These domes often collapse, leading to pyroclastic flows.
3. Famous examples include Mount St. Helens and Mount Pelee.
4. They form in both stratovolcanoes and independent eruptions.
5. Felsic lava typically contains rhyolite or andesite.
6. Lava domes indicate high-pressure magma chambers.

Additional Knowledge

• (a) Cinder cone: Small, steep-sided volcanoes formed from pyroclastic fragments.
• (b) Lava domes: Correct answer; mound-like features due to viscous lava.
• (c) Maars and tuff ring: Formed by explosive eruptions interacting with groundwater.
• (d) Caldera: Large volcanic crater formed by a collapsed magma chamber.