What is a flood basalt?
Q: What is a flood basalt?
A: A flood basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava.
Q: How large can flood basalts cover?
A: Flood basalts have covered areas as large as an entire continent in prehistory, creating great plateaus and mountain ranges.
Q: What causes flood basalts?
A: Flood basalts are caused by the combination of continental rifting and its associated melting, along with a mantle plume producing vast quantities of a basaltic magma.
Q: Where do flood basalts start from?
A: Flood basalts start at between 100 and 400 km depth, in the asthenosphere.
Q: What is necessary for partial melting to occur on such a large scale?
A: It is necessary to have a large heat input in order for partial melting to occur on such a large scale as that of the traps, expelling huge quantities of lava.
Q: Where does this heat input come from?
A: The heat input comes from near a hotspot, resulting in a mixture of magma from the depths of the hotspot with superficial magma produced by a mantle plume.
Q: How do we know that Earth has periods of higher activity rather than being in uniform steady state?
A: We know that Earth has periods of higher activity rather than being in uniform steady state because floods basalts have erupted at various times throughout Earth history - they are clear evidence for this fact.
