Interfacial friction-induced pressure and implications for the formation and preservation of intergranular coesite in metamorphic rocks

摘要: Abstract The finding of intergranular coesite and pseudomorphs has been taken as critical evidence to support that the formation was related to regional ultrahigh pressure (UHP) metamorphism rather than pressure-vessel effect. Previous laboratory deformation experiments found occurs in practically undeformed strain-forbidden zones immediately adjacent piston–sample interfaces while mean stress applied specimen is remarkably lower quartz–coesite equilibrium boundary. preservation eclogites from UHP metamorphic terranes occurrence within experimentally deformed rocks can be more satisfactorily explained by theory interfacial friction-induced pressure, which a well-known metal forging. During certain episodes fast tectonic under high transient differential stresses, friction induce very significant pressures thin layers weak materials (e.g., SiO2) between large garnet crystals are refractory mechanically strong, thus act excellent anvils. local deviates lithostatic value, likely an intrinsic property highly constrained flows strong walls at least on microstructural scale.