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How can lava flows form a plateau?
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mountain
Mount Sir Donald in the Selkirk Mountains, British Columbia,
looms
above
a segment of the Trans-Canada Highway.
A plateau can be formed when extensive lava flows, known as flood basalts or traps, along with volcanic ash, bury the preexisting terrain.1
This process typically occurs through the following mechanisms:
- Fissure Eruptions: Volcanic vents in the form of long fissures often erupt voluminous amounts of fluid lava, which can build up thick lava plateaus.2
- Distance of Flow: Because the lavas and ash are often carried long distances from their sources, the resulting topography is not dominated by individual volcanoes or volcanic centers.1
- Accumulation: The thickness of the resulting volcanic rock can reach tens to hundreds of meters, creating a top surface that is typically very flat, though it may later be marked by sharply incised canyons and valleys.1
These volcanic plateaus are commonly associated with hot spots and are often the result of rare, large-scale eruptions. Notable examples include the Columbia Plateau in the United States and the Deccan Traps in India.13