(1) The freezing of liquid water in the absence of pre-existing ice; see infiltration ice, recrystallization. (2) Addition of ice to the base of sea ice by freezing. If new and young ice are not deformed into rafts or ridges, they will continue to grow by congelation. Congelation ice has distinctive columnar crystal texture due to the downward growth of the crystals into the water. It is very common in Arctic pack ice and fast ice. In limnology it is called 'black ice'. Congelation derives from 'congeal', meaning freeze or thicken, increase in viscosity.