Ice Cores

Question 1

what are they?

Answer 1

they provide records of past climate and environmental variability, include oxygen isotope, past gas composition, volcanic ash etc. annual layering

Question 2

where do they come?

Answer 2

longest record from EPICA core dating back 800,000 yr, NEEM ice core is 125,000 yrs

Question 3

where do you take them from?

Answer 3

need to be a continuous record, where the ice is flowing the slowest, ice divides are the best location for this.

Question 4

what are ice divides?

Answer 4

horizontal flow velocity is very close to 0m

Question 5

what occurred at NEEM?

Answer 5

aimed to sample intact column however ice structures had heavily folded

Question 6

ice cores as paleothermometers?

Answer 6

oxygen has 3 isotopes O,16, O17, O18, analysis of ice cores focus on the ratio between O16, O18, H2O18 more likely to be precipitated out first due to being isotopically heavy

Question 7

importance of precipitation source?

Answer 7

oceans are composed of isotopically heavy water, O18 water in the ocean is harder to evaporate, once evaporated it is more likely to be precipitated out first, therefore ice sheets are delpeted in O18 water

Question 8

importance of precipitation path?

Answer 8

a larger path over the ocean for example results in different isotopes due to more O18 having been precipitated