They allow us to go back in time and to sample accumulation, air temperature and air chemistry from another time. Slow ice flow at the centre of these ice sheets (near the ice divide) means that the stratigraphy of the snow and ice is preserved. As the collisions tapered off the earth began to cool, forming a thin crust on its surface.
Cuvier established amongst the scientific community the fact of extinction.Drilling a vertical hole through this ice involves a serious effort involving many scientists and technicians, and usually involves a static field camp for a prolonged period of time. Shallow ice cores (100-200 m long) are easier to collect and can cover up to a few hundred years of accumulation, depending on accumulation rates. Clouds formed and storms raged, raining more and more water down on the primitive earth, cooling the surface further until it was flooded with water, forming the seas.It is theorized that the true age of the earth is about methods to determine the age of rocks means scientists have to rely on when the rock was initially formed (as in - when its internal minerals first cooled).In the very beginning of earth's history, this planet was a giant, red hot, roiling, boiling sea of molten rock - a magma ocean.