At high elevation this moisture is deposited as snow and later turns to ice. The team also plans to drill at a site located 30 kilometres away from the summit plateau at an elevation of 3,017 metres. This site is in the low troposphere, the atmospheric layer that goes up to seven kilometers in elevation. Researchers with Fisheries and Oceans Canada hope that information on pollutants found in ice cores drilled at this lower site will help to explain changes in productivity in the upper layers of the ocean. Ice cores from the two sites on Logan will also be compared with cores from the Devon Island Ice Cap, located in the eastern Arctic.
Moisture here comes from yet another source, Eurasia.
While the climate has been warming noticeably in the Yukon and Alaska over the last few decades, the eastern Arctic has shown no significant change during this same period. The situation is different over the long-term however. Temperatures gradually began to increase again, but in the eastern Arctic this warming leveled off very close to the time that pollution started to enter the Arctic at very high levels in the 1950s. An ice core has been drilled on Logan before. In the 1980s another team drilled down 100 metres, retrieving a core containing 350 years worth of ice layers.