Seven years ago, a team of scientists at Princeton University began researching ancient ice in the Allen Hills region of Antarctica. The object was the so-called "blue ice", which is approximately 2.7 million years old, which is 1.5 million years older than the previously obtained samples and occupies less than 1% of the surface of the 6th continent. The results of the work were reported during the next Goldschmidt conference on geochemistry in Paris.
Antarctic ice cores are a treasure trove for climatologists. Thanks to them, scientists have a unique opportunity to learn about climate change on the planet over millions of years. Air bubbles frozen in ice are a kind of chemical marker. By studying their chemical composition, scientists will learn about how the content of greenhouse gases in the atmosphere has changed.
However, the previous technology of vertical drilling did not give the desired results: the age of the obtained ice samples did not exceed 800, 000 years. Then the scientists decided to drill horizontal wells on the slopes of the Antarctic ridges, where, as it turned out, the oldest ice lies.
It was found that the content of CO 2 in the atmosphere at that distant time was only 300 ppm (molecules per million), which is about 100 ppm less than now.
Over time, scientists hope to get samples up to 5 million years old. The obtained cores will help to look into the era when the level of CO 2 on the planet was close to today, which allows to establish a historical relationship between climatic and atmospheric levels of carbon dioxide.