Greenland ice core dating
These successful but limited attempts were followed by the American-Danish-Swiss cooperative Greenland Ice Sheet Project (GISP-1) in southern Greenland from 1979 to 1981.From 1989 to 1992 the joint European Greenland Ice-core Project (GRIP) at Summit station in east-central Greenland drilled through 3,029 metres (9,935 feet) of ice before striking bedrock.Since then, they have revealed previously unknown details of atmospheric composition, temperature, and abrupt changes in climate.
Coring of mountain glaciers in tropical and subtropical areas must be kept from melting.
This suggests that greenhouse gas levels are linked to climate. Sulfuric acid is carried around the globe as an aerosol that strongly affects climate by reflecting sunlight back into space.
Hydrochloric acid (HCl) and hydrofluoric acid (HF) are also produced in volcanoes and are measured in the cores as total acidity. GISP-2 cores have revealed more than 300 major eruptions over the past 9,000 years.
This drill recovers a core several metres long and 10 cm (4 inches) in diameter.
The core hole is kept open with solutions that do not freeze in order to combat the pressure of the ice that would otherwise force the hole closed as progressively deeper cores are extracted.
These ratios are representative of precipitation and therefore ultimately reveal the composition of the source moisture, the sea.