User:Ppwu

Overview
Post-Glacial Rebound. By the end of the last ice age about 20,000 years ago, much of Northern Europe, North America, Greenland and Antarctica were covered by ice sheets up to three kilometres thick. The enormous weight of this ice caused the surface of the crust to deform and downwarp under the ice load, forcing the fluid mantle material to flow away from the loaded area. At the end of the ice age when the glaciers retreated, the removal of the weight from the depressed land led to uplift or rebound of the land and the return flow of mantle material back under the deglaciated area. Due to the extreme viscosity of the mantle, it will take many thousands of years for the land to reach an equilibrium level.

Studies have shown that the uplift has taken place in two distinct stages. The initial uplift following deglaciation was rapid, proceeding at about 7.5 cm/year. This rapid "elastic" phase took place as the ice was being unloaded. Once de-glaciation was complete, uplift proceed by "slow viscous flow" so the rate decreased exponentially after that. Today, typical uplift rates are of the order of 1 cm/year or less. This is clearly shown by the GPS data obtained by the BIFROST network. Studies suggest that rebound will continue for about at least another 10,000 years. The total uplift from the end of deglaciation depends on could be several hundred meters.

Recently, the term Post-Glacial Rebound is gradually replaced by the term Glacial Isostatic Adjustment. This is in recognition that the response of the Earth to glacial loading and unloading is not just limited to the upward rebound movement, but involves downward land movement, horizontal crustal motion, changes in global sea levels, the Earth's gravity field, induce earthquakes and also changes in the rotational motion.