 Based upon solid geological evidence, consisting largely of the analysis of numerous deep cores from coral reefs, variations in the rates of sea level rise have been reconstructed for the postglacial period.For the early part of the sea level rise that is associated with deglaciation, three major periods of accelerated sea level rise, called "meltwater pulses", occurred.They are commonly called "meltwater pulse 1A0" for the pulse between 19,000 and 19,500 calendar years ago; "meltwater pulse 1A" for the pulse between 14,600 and 14,300 calendar years ago and "meltwater pulse 1B" for the pulse between 11,400 and 11,100 calendar years ago.