2MSL

2MSL refers to Twice the Saturation Melting Limit. It is a concept used in the study of melting in geological contexts, particularly within the Earth's mantle. The saturation melting limit, or MSL, represents the maximum degree of partial melting that a rock can undergo before its composition changes significantly, leading to the separation of melt from solid residue. This separation is often driven by the density difference between the melt and the remaining solid phases.

The concept of 2MSL acknowledges that under certain conditions, the melting process might extend beyond the initial saturation limit. This can occur due to factors such as changes in pressure, temperature, or the addition of volatile components like water or carbon dioxide. When 2MSL is reached, it suggests a more extensive melt extraction or a more complex melting regime than that described by the simple MSL. Understanding 2MSL is important for interpreting seismic data and understanding the generation of magma in various tectonic settings. It helps geologists to better model the processes of melt generation, segregation, and ascent within the Earth's interior, contributing to our understanding of mantle dynamics and volcanism.