The Eliza and Ilka in the orange light logging cabin with red headlights.
June 29, 2023
The Eliza and Ilka in the orange light logging cabin with red headlights.
A very exciting day where we in the second ice core of the day saw particles in the ice core. We immediately switched to orange light in the logging cabin to avoid white light on the particles. One of the ways we can date the oldest ice is by using Optically Stimulated Luminescence (OSL) on mineral particles in the ice. While quartz and feldspar are covered by ice they are shielded from the sun and they trap electrons in their crystalline structure. Under the stimulation of light the trapped electrons may free themselves and the light emission from this process can be detected and it can be determined how long time has gone since they were exposed to sunlight. When exposed to sunlight or white light they are ‘bleeched’ and the information on age is gone.
Another exciting news is that a few O18 samples taken from left over pieces of the Physical Property part of the ice core by Nico has been brought to Copenhagen by Anders and measured by Vas. We see that the values abruptly change from high interglacial Eemian values to cold glacial values from ice from the previous glacial period. The deep glacial values are confirmed by 15 additional O18 samples made by scraping the surface of the ice cores from bag 4799 to 4813 (2639.45 m to 2647.15 m). As they can not be dated they are not shown on the plot but the O18 values are between -39.28 and -36.28‰.
What we did today:
Ad 1: After several short ice cores and attempt was made to put 250 g glycol as frozen pellets into the borehole before lowering the drill down. The first core drilled was 80 cm long.
Weather today: Overcast with light snowfall, ESE winds between 10 and 16 kt. Temperatures -5°C to -3°C.
FL, Dorthe Dahl-Jensen
The orange drill trench.
The O18 values of the deepest ice.