Flood basalt province
Also called: Fissure eruption, Plateau basalt, Lava plateau, Volcanic plateau · Topic: Interior of the Earth: Earthquakes, Volcanoes and the Layered Earth · NCERT: Class 6, Ch 3 "Landforms and Life"; Class 11, Ch 3 "Interior of the Earth"
Meaning
A flood basalt province is a huge area covered by thick sheets of basalt lava. Very fluid lava pours out of fissures, which are long cracks in the ground, not a single vent. The lava spreads over thousands of square kilometres. Single flows can be over 50 m thick and hundreds of kilometres long. Layer upon layer, they build a flat-topped lava plateau. These are the largest outpourings of lava on earth.
Example
The Deccan Traps formed about 66 million years ago. They cover most of the Maharashtra plateau and were once much larger. The basalt weathers into fertile black soil. The Columbia Plateau (USA) and the Siberian Traps (Russia) are other examples.
Don't confuse with
- Shield volcano: also made of fluid basalt, but it erupts from a central vent and builds a broad dome. A flood basalt erupts from long fissures and builds a flat plateau.
- Supervolcano: also huge, but explosive. It throws out more than 1,000 cubic km of material and leaves a giant caldera.
Related concepts
- Volcano
- Magma
- Lava
- Pyroclastic material
- Active volcano
- Shield volcano
- Cinder cone
- Composite volcano
- Caldera
- Supervolcano