Field Update: Nov. 19, 2010

The hot water drill hole has been melted through the full depth of the Ross Ice Shelf, which is approximately 250 meters thick from top to bottom in this area. We are now ready to start investigating the properties of the ice, the water, and the seafloor below. In order to sample the surface sediments on the seafloor, we plan to use a gravity corer – a large weight with a plastic tube attached to it – that we lower on a cable to just a few meters above the seafloor and then let it free-fall the last few meters to drive the tube into the surface sediments. We then pull back on the cable to collect a sediment core that we can recover back to the surface of the ice for study.

With a large hole melted through the ice shelf, we are focused on safety concerns, so everyone working around the hole wears a harness that is clipped to a safety line attached to an I-beam anchored to the steel frame on the top of the MECC. The safety line can spool out and in as you walk around the area, so its convenient, and you forget it’s there until it pulls you to a stop at a certain pre-set distance. The harness and line can support a person’s weight and two people can work comfortably around the hole while hooked in. Hedley, JR and Richard take turns working around the hole to deploy and recover the gravity corer, while Tristan operates the AWI winch.

Claude Laird wants to look down the hole, so he gets a harness on and then takes a look down hole as Hedley shines a light into the abyss.

Claude was born in the state of Nebraska, so he likes his new UNL hat.

The winch used for gravity coring is from the Alfred Wegener Institute (AWI) in Bremerhaven, Germany. It has a number of levers and controls.

The cable (rope) goes through a counter so we can tell the amount deployed. Richard puts on the harness and gets hooked in. You can see that he likes this work and looks forward to getting the first core at this site.

Richard and Hedley wait like expectant fathers as the core barrel is pulled up the hole, waiting to see what length of core we’re going to get. The first core of the season is 17 cm long and everyone is happy to see the sediment.

Daren, an ice-driller is fascinated. Graham, who has never seen a core and just stepped out of the bath, squeezes a piece between his fingers and remarks: “So that’s what all of the excitement is about – mud”!

The team replaces the cover over the hole and gets ready to prepare for the next run down the hole. The coring has started, but there’s more work to do.

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