GLACIATION AND ISOSTASY

            Glaciation is a process of accumulating snow into a large block of ice. This block of ice is called glaciers. This process of glaciation occurs commonly in cold environment that has a sufficient amount of snowfall. Although most Glaciation take place in the polar region, glaciation also appeared in the high mountains of tropical areas.

            Isostasy is the concept of floating Earth’s crust to maintain gravitational equilibrium. The concept is similar to a floating wooden block above water. Since water is denser than the wood, it makes the wooden block float. When woods float, another behavior is also observed. The thicker wooden block floats higher than the thinner ones. It also has deeper root that are covered by water.

            Glaciation is related with the concept of isostasy in two ways. First is the effect of glacier’s presence on the continent. Second is the glacier’s behaviour when floating free in the oceans as icebergs.

1.        Continental thickening

Glaciers covers approximately 10 percent of the total land area on Earth. Most of them are located in Greenland and in Antartica. Glaciers at this place are so thick they can reach the thickness of 4300 meters in Antartica. In addition, glaciers of Antartica covers around 80 percent of world’s ice. So if they melt, sea level worldwide would rise to 70 meters.

This huge block of ice give additional weight to the underlying crust. Because of the massive size, additional weight is sufficient enough to cause uplifting of the crustal root. Meaning that the crust in these area have deeper root to maintain balance with the additional ice weight.

2.        Floating icebergs

In Greenland, lots of glaciers melts and brakes into large icebergs. Those iceberg than floats south-wards to the Atlantic Ocean. Free floating iceberg are nightmares to sailors. The most famous one is the sinkage of Titanic a century ago.

Icebergs cause accidents as only small portion of the ice are floating above water level. Meanwhile huge block of it is covered underneath. Thus iceberg is not very visible from distance. Sailors may only realize the iceberg as they approach near.

The behaviour of iceberg here is also similar to the uplifting of crustal root in antartica. Both behaviour take place in order to maintain gravitational balance.