ABSTRACT Carboniferous speleothem calcites in un-metamorphosed limestones from South Wales exhibit crystal diminution (degrading neomorphism) textures. These textures result from processes which have been considered only important under metamorphic conditions. The textures are interpreted as the result of recrystallization associated with dislocation processes. These processes relate to low temperature creep associated with low strain rates extended over long periods of time. The textures described here occur in unusually large crystals but similar textures have been described in limestones from deep boreholes. Dislocation processes, recovery and recrystallization are likely to be important processes operating during deep burial diagenesis.