Dating antarctic ice cores
Measuring the delta value at many depths through the ice core is equivalent to measuring the air temperature at many times in the past. Climatic temperature against time from delta measurements taken on the ice core drilled at the Russian station, Vostok, in central Antarctica (Figure 2).Available data from this ice core so far extends back about 160,000 years.To identify the oldest Antarctic ice likely to yield good cores, the team used climate and ice condition data and modeled heat and ice flow on the continent.The best locations to find such ice were near the bottom of East Antarctica at the Domes, the highest points on the ice sheet, as well as near the South Pole.Approximately 98 per cent of the Antarctic continent is covered by the ice sheet which is on average about 2,500 metres thick and, at it's deepest location, 4,700 metres thick.It is due to this thick ice mass that Antarctica is, on average, the highest continent.Regions of Antarctica could hold 1.5-million-year-old ice that would reveal key parts of Earth's ancient climate history, new research suggests.
There are several possible reasons for this: there may also have been more storms, or at least more violent storms.
From about 18,000 or 19,000 years ago to about 15,000 years ago, the climate went through another warming period to the next inter-glacial, - the one we are now in.
Figure 2 also includes a graph of the concentration of dust in the ice core.
As the snow is deposited on top of the ice sheet each year, it traps different chemicals and impurities which are dissolved in the ice.
The ice and impurities hold information about the Earth's environment and climate at the time of deposition.