The theory of mantle plumes states that mantle plumes originate deep in the mantle, perhaps at the core-mantle boundary. Plumes originate from a thermal anomaly (an unusually hot patch) and rise buoyantly through the mantle because they are hotter than the surrounding rock. The plume consists of a large head and narrow tail (shaped kind of like a mushroom). When the plume hits the base of the lithosphere, it spreads out and also undergoes decompression melting (i.e. melting due to a decrease in pressure), producing large volumes of magma.The resulting volcanic centers are known as hot spots.
Mantle plumes have been a topic of scientific debate in recent years. While most earth scientists accept the theory, there are many who question it and propose alternate explanations of hot spots.
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