Evolution of serpentinite oceanic textures across Alpine metamorphism: neutron radiography and computed tomography

Serpentinisation of oceanic mantle is one of the most important mineralogical reactions in the Earth Science. This reaction involves the interaction between the upper mantle mineral with seawater at temperatures ranging from 100 to 350oC and produces a magnesium-rich hydrous silicate, serpentine ((Mg,Fe)3Si2O5(OH)4). Once subducted the seperntinised oceanic lithosphere is believed to play a major role in supplying water to the overlying mantle wedge and may trigger intermediate earthquakes. Recovered serpentinised rocks are useful in understanding the high-pressure and high-temperature behaviour of the serpentines encountered in subducted slabs and show textures that are partly preserved from the oceanic process. It is the aim of this study to use neutron tomography to obtain the three-dimensional distribution of the hydrous phases in serpentines recovered form the Western Alps.