2/10/2014 – Entering Totten

Michelle writes:

1-P1010313We are just about 6 nautical miles from the edge of the Totten ice band and should be able to break through the sea ice into some ice-free water adjacent to the coast by this evening. Our watch shifts now demand a higher level of attention because we are in un-chartered waters; there is no pre-existing data from this area. Every seafloor feature that shows up on the screen on the Knudsen bathymetric profiler has never been seen before. NBP14-02 will be the first cruise to survey the seafloor and collect geological and physical measurements of the sediment and ocean currents.

Now, all planning is in overdrive. At the transition between shifts, there is usually a PI meeting at the navigation table or in the Chief Scientist’s room. These meetings include deciding which sites to hit first, which group will run their instruments and in what order. As we steam toward Totten Glacier, the researchers running the seismic instruments are planning their lines (the distance between two waypoints on which they will make their measurements).

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These images are very important because they will be high-resolution images of the ocean bottom and the sub-bottom down to about 400 m. That is tens of millions of years of a sediment record in one picture. The seismic images show the various layers and points of contact between geologic periods. For example, we may be able to see the boundary between the Eocene and Oligocene. Continue reading

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2/5/2014 – Multibeam, Multichannel, and Maybe Multidredge

Katy writes:

Mertz Trough sea ice

Mertz Trough sea ice (click to enlarge)

When we started our shift, the multichannel seismic streamer had just been deployed to start its 16-hour survey. This is the maximum continuous operational time for this instrument because our marine mammal observers, Tasha Snow (USF) and Andrea Walters (University of Tasmania), have to be on watch while it’s in the water, and each of them is only permitted to do an 8-hour shift. We anxiously awaited the data to be processed by Bruce Frederick and Sean Gulik (University of Texas at Austin), our resident seismic experts on the night shift.

These data are very important not only for determining core and dredge sites on our cruise but to add to the support of an IODP (Integrated Ocean Drilling Program) proposal for this area. The proposed drill cores will be approximately 80 meters in length will help scientists to observe and analyze how climates (particularly ice sheets) respond to increased CO2. The specific goals of the proposal are to address the timing of “the Eocene-Oligocene ice advance (~34 Ma), the mid-Miocene climate transition (~14 Ma) and the earliest Pliocene warmth and climate fluctuations (~5 Ma).” Everyone was very excited about the data that we collected and now it was time to pick dredge locations!

PIs reviewing the processed seismic data

PIs reviewing the processed seismic data

Although our watch was dominated by this seismic data and activity, I had a lesson with Caroline Lavoie (Universidade de Aveiro), one of our multibeam specialists. We discussed how to process the data that we were receiving hourly from the multibeam system and about the CARIS system in general, which we use to process the data. Continue reading

2/4/2014 – The Method to the Madness

Michelle writes:

There is so much planning that goes into making these research cruises a reality.  Multiple conference calls, pre-cruise meetings, travel and lodging logistics, coring and site survey selection- all of these things spread over years. All that planning gets us on the ship … and then we have to adjust many well-laid ideas to suit the environment. Amelia tells us that as a PI (Principal Investigator), it’s not enough to have a Plan B; you have to have Plans A through Z.

So far, we're on Plan F

So far, we’re on Plan F

Weather and ice conditions change so fast down here, so all the PIs need to be flexible with their own sampling strategies as well as accommodate each others’ scientific objectives. That means when we finally get into the ice, plans change; the decisions that dictate those plans are carefully weighed and executed. Going into this cruise, I knew there must be a whole list of reasons for choosing a core site. Now, 8 days in, I am finding out just how many factors contribute to our PIs’ decision and I am astounded at their combined knowledge. Continue reading

2/3/2014 – Mertz Glacier Science Plan

Tasha writes:

Today marks the beginning of our sixth day underway and the crossing into the beginning of an entirely new world. We crossed 60 degrees south and have committed to continuing our travel directly south to the Mertz glacier; we expect to make it to the edge of the continental shelf on the morning of the 4th. To prepare us for our arrival in East Antarctica and for the beginning of a flurry of science that will be taking place, we listened to a couple of brief science talks about past science and our current objectives at the Mertz glacier.

And after that, we didn't let the penguins drive the boat any more...

And after that, we didn’t let the penguins drive the boat any more…

One of our objectives will be to acquire geophysical (seismic) survey data that will satisfy the requirements for future deep sediment drilling in the area. Seismic surveys will be conducted using two air guns that transmit sound pulses to the sea floor. This energy is powerful enough to penetrate 1 or 2 kilometers down into the sediment and underlying bedrock basement. When the sound waves encounter density changes in the stratigraphic layers (e.g. transitions from clay to bedrock), some of the energy reflects back up to the surface of the ocean where we have a seismic streamer (array of hydrophone receivers) that will detect the sound and record it.

Vessel telemetry, 3.5 kHz sub-bottom profiler, multibeam sonar, and other assorted toys

Vessel telemetry, 3.5 kHz sub-bottom profiler, multibeam sonar, and other assorted toys

We then translate the recorded sound to an image that will be used to create a map of the sediment layers below the seafloor. The map is based solely on the time it took for the sound to travel from the guns into the sediment and back to the receivers. These maps of the sub-bottom have many applications. Continue reading

1/29/2014 – Field Trip Flashback

[Check out the Facebook page for more photos that we couldn’t squeeze into the blog entry. This link to the album will work even for those without a Facebook account.]

Katy writes:

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Gene Domack, one-man supergroup

Although most of our time in Hobart was allotted to preparing the ship to set sail, we were able to spend a day looking at the geology and ecology of Tasmania with Gene Domack, who has done significant research throughout Tasmania since 1988. On Monday, we ventured outside of Hobart to Mount Field National Park in Maydena. We went to Mount Field to see the magnificent Russell Falls and the great exposure of certain formations of the Parmeener Supergroup. We discussed how the Supergroup sits on the central plateau of Tasmania, which formed during the Late Paleozoic accretionary event when Gondwana assembled. The Parmeener Supergroup ranges from Carboniferous to Jurassic in age, and includes the last evidence of ice at sea level on the planet until the Cenozoic.

At this location, we were standing on the Permo-Triassic boundary, which was the time of the biggest extinction event on Earth and marked the transition between the Paleozoic cool, humid “icehouse” environment to the Mesozoic warm, arid “greenhouse” environment. The Parmeener Supergroup is analogous to the Beacon Supergroup in Antarctica, along with other Gondwanan stratigraphy in Africa, India, and South America. By studying this stratigraphy, we can see the connections between continents when they were together and determine past climates and past continental positions.

Russell Falls

Russell Falls

The Supergroup begins with a tillite layer that we saw in an outcrop outside of Maydena, which is Carboniferous in age. Above that is a fossiliferous mudstone that has been dated to 294 +/- 7 million years, which is the base age of the Permian and may also contain evidence of 42,000-year Milankovich cycles. In the stratigraphy, we see that the tillite immediately transitions into the shale layer rich in Tasmanities, which are green algal cyst deposits that live in an open marine pelagic environment. Analyzing the stratigraphy and fossil evidence allows us to determine that the transition between and glaciated environment and a marine environment was immediate in geologic time. Continue reading

1/28/2014 – Cruise Preparations

Tasha writes: 1-P1010284 Excitement is building now that we’re almost ready to sail. By the time you read this, in fact, we’ll probably be well underway. Research time during this cruise will be split evenly between three groups: physical oceanography, seismics, and marine geology and geophysics (MG&G). Our group, the MG&G group, is comprised of the following people. Principal Investigators:

  • Chief scientist, Dr. Amy Leventer (Colgate University)
  • Dr. Amelia Shevenell and Dr. Eugene Domack (USF) 

Graduate students:

  • Michelle Guitard, Katy Smith, and Tasha Snow (USF)
  • Kelsey Winsor (OSU)

Undergraduate students:

  • Mikhaila Redovian and Kara Vadman (Colgate University)
  • David Morgan (Hamilton College)
Gene Domack shares with the students some insights gleaned from three decades of Antarctic research. Number one: Look around. This is not Antarctica.

Gene Domack shares with the students some insights gleaned from three decades of Antarctic research. Number one: Look around. This is not Antarctica.

Since our arrival in Hobart, Tasmania, we have been steadily working together to prepare the ship for the six-week research cruise. When we first stepped onto the R/V Palmer for the cruise, we found the labs completely bare; they had just been stripped down by the outgoing science crew and were ready for the incoming group of scientists to set them up in a way that best facilitates the new research demands. That would be our primary focus for the four days before the cruise.

Core lab ready for transit. The calm before the storm.

Aft dry lab ready for transit. The calm before the storm.

We began transforming the lab on Saturday, Jan 25th, by unpacking all of our supplies: sediment sampling tools, vials and bags for carrying samples, and a cornucopia of other odds and ends that together make scientific research possible. We strategically arranged lab benches to accommodate 6-meter (20ft) long jumbo kasten cores and leaving space to move around the core in the limited lab space; the process became more of a game of Tetris than lab setup.Next, we built jumbo piston core racks as well as our magnetic susceptibility (MS) system with core tracks and electronics that will be used to measure the amount of magnetic material in the cores (like magnetite). We secured all equipment and boxes for sea by bolting down all loose tables, using ropes and bungees to tie any loose items to the table legs, and fixing any drawers that do not latch properly. This will prevent drawers from ceaselessly banging open and closed, boxes sliding around the room dumping their contents, and objects becoming missiles during heavy seas.

To wrap up our preparations for the transit south, we cleaned all of the lab benches and cabinet doors for radiocarbon, first with soap and then ethanol. Cleaning will help to prevent the radiocarbon contamination of our sediment samples that would artificially alter our radiocarbon dating measurements. After being cleaned, lab benches were covered with bench paper and our facility preparations complete. Now as we set sail on our long voyage to the East Antarctic, the lab will be ready for any sort of event we might encounter. Continue reading

1/27/2014 – A Long Way Here and a Long Way to Go

Michelle writes: 

This is only my first blog post and barely my fourth day in Hobart, Tasmania, but I already feel like I left home ages ago. Perhaps this is because it took about 30 hours of traveling to get from Florida to Tasmania, or maybe because I have been busy every day. Or maybe I am finally beginning to realize how much work we have to do and the weeks are stretching out endlessly in front of me.

The Palmer still working on her tan

The Palmer still working on her tan

That sounds like I am dreading this cruise- quite the opposite! I am so excited to finally be here and have the opportunity to contribute to the understanding of changing ice dynamics in East Antarctica. I think the reason I feel so removed from what I consider “normal life” is because the cruise is really a whole different ballgame. First off, it spans 46 days. It will take 7 days just to get down to Antarctica, and then there is a solid month of work surveying and sampling the continental shelf from the George V Shelf up to the Totten and Shackleton glaciers. Second, our study area is so isolated and the elements are so extreme, it’s enough to make anyone feel slightly anxious. And third, this cruise has been in the works for many years, with many smart and experienced scientists spearheading the effort. Continue reading