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Hand augers can be rotated by a T handle or a brace handle, and some can be attached to handheld electric drills to power the rotation.
Numerous other deep cores in the Antarctic have been completed over the years, including the West Antarctic Ice Sheet project, and cores managed by the British Antarctic Survey and the International Trans-Antarctic Scientific Expedition.It can be up to about 20 m thick, and though it has scientific value (for example, it may contain subglacial microbial populations), Cores are often drilled in areas such as Antarctica and central Greenland where the temperature is almost never warm enough to cause melting, but the summer sun can still alter the snow.In polar areas, the sun is visible day and night during the local summer and invisible all winter.Ice cores are collected by cutting around a cylinder of ice in a way that enables it to be brought to the surface.Early cores were often collected with hand augers and they are still used for short holes.Ice cores have been studied since the early 20th century, and several cores were drilled as a result of the International Geophysical Year (1957–1958).
Depths of over 400 m were reached, a record which was extended in the 1960s to 2164 m at Byrd Station in Antarctica.
The bubbles disappear and the ice becomes more transparent.
The weight above makes deeper layers of ice thin and flow outwards.
The proportions of different oxygen and hydrogen isotopes provide information about ancient temperatures, and the air trapped in tiny bubbles can be analysed to determine the level of atmospheric gases such as carbon dioxide.
Since heat flow in a large ice sheet is very slow, the borehole temperature is another indicator of temperature in the past.
Cores are drilled with hand augers (for shallow holes) or powered drills; they can reach depths of over two miles (3.2 km), and contain ice up to 800,000 years old.