In the picture above, you’ll see that the ice core is in a green netting. Any guesses as to why we’d put the ice core in netting? Well, it is because we have reached what ice core scientists call “brittle ice”. Brittle ice occurs with depth in an ice sheet where the tiny air bubbles that are trapped inside the ice are under high amounts of pressure. When we bring the ice up to atmospheric pressure very quickly, the tiny bubbles want to burst because they no longer have as much pressure pushing on them. By handling the ice core and moving it around, we can actually induce breaks and fractures in the ice because the bubbles are very pressurized. We want to reduce the amount of breaking because our goal is to preserve the trapped ancient air to study it! In order to prevent excessive breaking, we immediately put the brittle ice cores inside netting to help reduce damage to the core and ensure that if breaks or popping occurs, the pieces stay in the right spots. These cores are then kept in our ice storage trench over the winter to provide more time to relax the internal stresses and next year we will processes them and get them ready to be shipped back to the National Ice Core Lab (NICL) in Denver, CO. .
The core also has drilling fluid on its exterior and we don’t want to ship drilling fluid back to NICL for several reasons. The first is that the drill fluid is not cheap and we want to recycle and reuse as much as possible. Recycling the fluid keeps us from having to ship more all the way to the South Pole. Also, the drill fluid we are using does have a slight smell that we don’t want to get stuck in a freezer for many years. Therefore, to remove the drill fluid from the netted ice cores, my job is to vacuum the core! This procedure removes quite a bit of the drill fluid. It is also very relaxing for me – makes me feel like I’m at home cleaning my house :)
On average, we drill about 24 meters per day between two 10-hour shifts. Each run of the drill is taking slightly longer because the drill has move distance to travel each time it goes up and down the borehole. A typical run from surface, down to drill and collect a 2-meter long core, and back up to the surface takes close to an hour. It is amazing to think that the drill goes nearly half of a mile down into the ice sheet and back up with more ice core in just an hour! AH, ice core science and engineering are so amazing.
Hope you all are staying warm in you respective homes. It’s currently -48 deg Celsius here (-47 deg F)!
Until next time,