megatermelt

Megatermelt is a hypothetical geological process that describes the melting of large volumes of rock deep within the Earth's mantle. It is a concept that arises in discussions of mantle dynamics and the generation of large igneous provinces. The term suggests a scale of melting far beyond that typically associated with normal mantle convection or the formation of small intrusions.

The idea behind megatermelt is that under specific conditions, perhaps related to mantle plumes or the accumulation of radioactive isotopes, a significant portion of the mantle could undergo adiabatic decompression melting, leading to a massive outpouring of magma. This magma would then rise to the surface and erupt, forming extensive lava flows and intrusive bodies that characterize large igneous provinces.

While the term itself is not a universally accepted or formally defined geological term, it serves as a descriptive shorthand for exceptionally large-scale magmatic events. The processes that would lead to megatermelt are thought to involve deep-seated mantle upwelling, potentially from the core-mantle boundary, that brings hotter, less dense material closer to the surface. As this material rises, it experiences reduced pressure, causing it to melt.

The consequences of a megatermelt event could be profound, including significant volcanic activity, atmospheric changes due to the release of gases, and potentially influencing global climate. The study of large igneous provinces provides evidence for the kinds of immense magmatic events that the concept of megatermelt attempts to describe.