We arrived at the Umnak Plateau this afternoon and are anxiously awaiting the first core. As one of eight sedimentologists on this leg, I know that I am about to become unbelievably busy, and this free moment feels like the quiet before the storm. We will work as 2 teams to describe every single section of every single core that we retrieve. You can be sure that if we recover even a small layer of volcanic ash or shell fragment, one of us will note it in the massive database. We’ve had long discussions about what we will call “sand” and what we will call “nannofossil bearing radiolarian diatom clay” and we’ve practiced all the analyses that we will be performing on every core. The labs are clean and the database is ready for data.
Outside the ship, it’s another story. The drillers and roughnecks are extremely busy right now. All afternoon we’ve been able to hear the booming and banging of “tripping pipe” and occasionally the JR will tremble like we’re experiencing an earthquake. On the drill floor, the drill bit and 60 long pipes are being fit together so that they will reach 2000 meters below the ship to the seafloor.
It’s quite exciting to be at the Umnak Plateau because I have spent the last 5 years thinking and writing about this very site in my master’s and PhD. Last night one of the other sedimentologists ran in and said, “You can see a lighthouse!” So, we rounded up everyone in the labs, donned our jackets and hats and trooped up to the bridge. When we opened the door, we stepped out into a pitch dark fog. Away in the distance we could see a small light flash on and off. It wasn’t quite the image I had in my mind of a picturesque light house, but it was exciting none the less because we were sailing through Unimak Pass—one of several passes between the Aleutian Islands—where Pacific water flows into the Bering Sea. During glacial periods, sea level is a lot lower than now, and Unimak Pass becomes land, essentially cutting off the flow of Pacific water. You can see this transition and others like it when you look down cores from the Umnak Plateau. And this is the reason that we’re all here—to read the history of ocean currents and climate in the cores that will soon rise from the sea floor to fill the lab.
But for now, we’re waiting, working on a few last minute preparations, and heading outside to watch periodically. A small pod of dolphins has been fishing around the JR since we arrived on site, but the highlight for me was a sea lion who swam back and forth along the port side of the JR and then surfaced and rubbed his face with his flippers! I’m hoping that these wildlife sightings keep up!
Photo above: Chart of Unimak Pass. credit: Gretta Bartoli .