Ice and Medicine at the end of the earth

Archive for February, 2015

The South Pole Ice Core

I’ve posted plenty about life at the South Pole, but what about the science? We recently completed our first drilling season, reaching a depth of 736 m.

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We are drilling an ice core at South Pole because of the unique climate here. South Pole is cold, even by Antarctic standards. It is the coldest spot for a deep drilling project by the USA. Other cores have been drilled at colder sites, but what makes the South Pole unique is that has received much more snow than those other sites.

More snow means higher resolution. Basically, if it snows twice as much, we collect twice as much ice for a given time period allowing us to make more detailed measurements. We also benefit from the atmosphere being trapped in the bubbles in the ice faster.

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The cold temperatures are necessary to preserve trace gases. When I say trace gases, I don’t mean carbon dioxide (CO2), which is measured in parts per million, or methane (CH4) which is measured in parts per billion. I mean gases like carbonyl sulfide (COS – that’s CO2 with an S instead of the second O) which is measured in parts per trillion. COS gets lost in warm ice, so the cold is needed to preserve it.

At 736 m, the ice is about 10,000 years old. After drilling to 1500 m next season, we will be at about 40,000 years. Each layer of ice gets thinned by ice flow which is why more time is packed into each meter of the deeper ice.

Once we have gotten the ice back to the US, we will begin the scientific analysis

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