Question of the reader - the answer of a scientist
How are ice samples from Antarctica extracted, stored and transported?
Ice samples in Antarctica are obtained by drilling wells.
It is difficult to drill ice: ice is a viscous liquid, and at great depths there are very large crystals, where the ice temperature is high - it approaches the melting point. Therefore, the well floats quickly if left unattended. You need to keep it in working order.
But over half a century of drilling, specialists have learned how to drill even kilometer-long wells: now the deepest well in the world is 3,769 meters. It is located in the area of the subglacial Antarctic Lake Vostok.
It is difficult to drill ice: ice is a viscous liquid, and at great depths there are very large crystals, where the ice temperature is high - it approaches the melting point. Therefore, the well floats quickly if left unattended. You need to keep it in working order.
But over half a century of drilling, specialists have learned how to drill even kilometer-long wells: now the deepest well in the world is 3,769 meters. It is located in the area of the subglacial Antarctic Lake Vostok.
Ice cores are extracted from the wells - ice cylinders with a diameter of about 10 centimeters. At the time of drilling, the length of the cylinder can be up to two meters, but then it is cut into pieces a meter long - this is more convenient to store. And it also helps in the calculation - if you cut the ice core into meter pieces, then the serial number of the ice core will correspond to the depth from which it was mined.
Basically, the ice core is stored in Antarctica: an ice core storage is arranged under the snow, and most of the extracted ice core is kept there. Polar explorers from Antarctic stations deliver to Russia only those samples that are needed for analysis.
Ice for different types of analysis is stored and transported in its own way.
For example, samples for isotopic analysis need the simplest conditions. Very little material is required – the ice core is cut with a saw into thin pieces 5 or 10 centimeters long, and even samples from the outside of the ice are suitable. Then the pieces are sealed in plastic bags and transported frozen. But even if something happens on the road and the ice core in the boxes melts, it will still be suitable for isotopic analysis - the isotopic composition of ice does not change during melting.
But for chemical or biological analysis, such samples are not suitable. They should be taken from the middle of the ice core to avoid possible contamination. And if the samples melt, they will have to be thrown away.
The most difficult thing is to bring samples to study the physical properties of ice. Even if ice is stored at –10 ° C, its properties change quickly. The naked eye does not notice this: the crystal structure of the ice and its volume change, its density slightly decreases, the ice expands, because the air bubbles in it are under pressure and tend to break it.
To protect ice from these processes, it must be stored at a temperature of –50 ° C - then it can be stored for several years. But these conditions are difficult to ensure, therefore such analyzes are often carried out directly in Antarctica - it is easier to bring the device to the ice than ice to the device. The ice core is removed from the borehole and examined in situ.
Basically, the ice core is stored in Antarctica: an ice core storage is arranged under the snow, and most of the extracted ice core is kept there. Polar explorers from Antarctic stations deliver to Russia only those samples that are needed for analysis.
Ice for different types of analysis is stored and transported in its own way.
For example, samples for isotopic analysis need the simplest conditions. Very little material is required – the ice core is cut with a saw into thin pieces 5 or 10 centimeters long, and even samples from the outside of the ice are suitable. Then the pieces are sealed in plastic bags and transported frozen. But even if something happens on the road and the ice core in the boxes melts, it will still be suitable for isotopic analysis - the isotopic composition of ice does not change during melting.
But for chemical or biological analysis, such samples are not suitable. They should be taken from the middle of the ice core to avoid possible contamination. And if the samples melt, they will have to be thrown away.
The most difficult thing is to bring samples to study the physical properties of ice. Even if ice is stored at –10 ° C, its properties change quickly. The naked eye does not notice this: the crystal structure of the ice and its volume change, its density slightly decreases, the ice expands, because the air bubbles in it are under pressure and tend to break it.
To protect ice from these processes, it must be stored at a temperature of –50 ° C - then it can be stored for several years. But these conditions are difficult to ensure, therefore such analyzes are often carried out directly in Antarctica - it is easier to bring the device to the ice than ice to the device. The ice core is removed from the borehole and examined in situ.