Category Archives: IODP Exp 374

Core on Deck

A core being carried onto the catwalk by IODP technicians during Expedition 374

This is the phrase that participating scientists on IODP expeditions love to hear. When a new core is brought up to the rig floor of the JOIDES Resolution (the JR) from beneath the seafloor, the driller’s announcement of “core on deck” comes through the speakers in all the labs. At this point, multiple people leap into action and prepare for the new core. The IODP technicians get ready to accept the (hopefully full) 9.5 meter (~30 ft) long core. The drilling crew lays the core down horizontally on the drill floor, with the base of the core facing the ‘catwalk’, and a technician will get small piece from the base of the core (called the core catcher) and hand it off to one of the paleontologists.

The paleontology lab will immediately start to process the sediment to isolate and identify microscopic fossils and fossil fragments that will provide information about the age of the deposits (an application of paleontology called biostratigraphy). The rest of the core is put on a rack on the catwalk at which point the IODP curator will measure, assign identification to the core, and prepare it to be cut into 1.5 m long sections. Once the sections are created they are carried into the lab and put on a rack to equilibrate to surface temperatures (~4 hours).

The whole-round core sections will then go through a series of measurements (natural gamma radiation, magnetic susceptibility, P-wave velocity, bulk density) that aid the science party in characterizing the sediments even before they are split. The IODP techs will then split the cores, creating a ‘working’ half and an ‘archive’ half. The working half is sampled for additional measurements (density, moisture content, porosity, paleomagnetics, geochemistry, paleontology) and the archive half is thoroughly described. By the time any single core makes it through this process, the biostratigraphy lab team will have a preliminary age for that core. (In some cases, they have an age within 10 minutes of getting the core catcher!) The paleomagnetism lab team will also generate an age model based on magnetostratigraphy, which can be compared with the paleontology team. After ~24 hours of that core coming on deck, the geochemistry lab team will have initial results about general composition (e.g., % of calcium carbonate). This shipboard characterization provides the foundation for research that is done several years or even decades after the expedition.

Photo from a drone during Exp 374 taken by IODP photographer and imaging specialist Bill Crawford

The JOIDES Resolution (JR) is a unique science vessel. There are many ships that can perform any number of tasks for oceanographic and marine science. But, the JR is different because it’s a time machine. Only through deep coring into the seabed can we extract the record of past processes and environments.  The sound of “core on deck” is music to the ears of geoscientists on board excited to make new discoveries about how the Earth works.

More photos of Exp 374 here:

The Transit from New Zealand (43°S) to the Ross Sea (76°S)

We left port at Lyttelton, New Zealand just over a week ago and have been cruising almost due south ever since. In ~36 hours we will rendezvous with the R/V Palmer, a polar-class icebreaker, who will escort us through some sea ice. The sites we plan to drill are in ice-free areas (called polynyas) but we need the icebreaker escort to get us to those areas. At some point before our rendezvous with the Palmer, we will cross both the Antarctic Circle (66°33′,47”S) and the International Date Line. (However, we will be staying on NZ time to avoid mass confusion!)

The transit included a few days of some high winds and up to 6 m high waves. The Southern Ocean (the ocean surrounding the Antarctic continent) is notorious for this kind of weather and, although it wasn’t as bad as it can get, it was still a rough ride. Thankfully, I do not get seasick, but several others in the science party weren’t feeling particularly well. Here’s a video from the bridge of the JR the other day showing the ~6 m waves (with bonus albatross).

The seas have calmed down a bit and the science party has begun moving on to their shifts (either noon-to-midnight or midnight-to-noon). I’m writing this post as I try to remain awake after staying up all night in an attempt to transition to the midnight-to-noon shift. Up until today, the science party has been all in a normal day shift and working in their lab teams to learn procedures. It’s a challenge to effectively ‘practice’ what we’ll be doing without core actually coming up, but it’s still a good idea to get some familiarization with the equipment and overall workflow. I’ll write more about what analyses are done and what data are collected in a future post.

We’ve also spent time during the long transit to learn more details about the coring operations (via tours and presentations; photos below) and to write/edit the methods sections for the expedition report that we, as a collective, will be creating as we go.

When we get to our first drilling location we will have traveled 33 degrees of latitude (from 43°S to 76°S), or approximately 3,660 km (2,270 miles) during this transit. The Earth’s oceans are vast, the JR is designed for long transits to get to where we need to go.

Getting ready to set sail

I’ve been in Lyttelton, New Zealand (port town close to Christchurch) the past few days during our port call. The science party typically boards and moves onto the JOIDES Resolution (the JR) during port call to begin getting familiar with the ship, the labs, the people, and more before we actually depart. Meanwhile, the crew for the ship is offloading cores (and other freight) from previous expedition and preparing for the new expedition. All this typically takes a few days, which allows the scientists to get off the ship in the afternoons/evenings.

We set sail in just a few hours and it will be an ~8-day transit to our first coring site in the Ross Sea. During this transit we will continue to work in our lab groups (more about all that in a subsequent post) and get ourselves ready for the first core on deck.

Being able to get off the ship also allows getting a view looking back at the JR from off the ship, which is something we won’t be able to do for two months. What a beauty!

Finally, just wanted to point to this very nice story by the College of Science communications team that was posted on Virginia Tech News the other day. This is a wonderful overview of the objectives of the expedition.

Brian Romans to sail on IODP Exp 374 to study West Antarctic Ice Sheet history

I’m very excited to announce that I will be participating as a shipboard scientist on International Ocean Discovery Program (IODP) Expedition 374. This expedition leaves Christchurch, New Zealand on January 4th and will spend several weeks in the Ross Sea, offshore western Antarctica.

Here is a detailed description of the scientific objectives of this expedition (copied from the expedition webpage):

The Ross Sea West Antarctic Ice Sheet (WAIS) History Expedition will investigate the relationship between climatic/oceanic change and WAIS evolution through the Neogene and Quaternary. Numerical models indicate that this region is highly sensitive to changes in ocean heat flux and sea level, making it a key target to understand past ice sheet variability under a range of climatic forcings. The proposed drilling is designed to optimize data-model integration for improved understanding of Antarctic Ice Sheet mass balance during climates warmer than present. Core and log data from a transect of six sites from the outer continental shelf to rise in the eastern Ross Sea will be used to: (1) evaluate WAIS contribution to far-field ice volume and sea level estimates; (2) reconstruct ice proximal atmospheric and oceanic temperatures to identify periods of past polar amplification and assess forcings/feedbacks; (3) assess the role of oceanic forcing (e.g., sea level, temperature) on WAIS instability; (4) document WAIS sensitivity to Earth’s orbital configuration under varying climate boundary conditions; and (5) reconstruct eastern Ross Sea bathymetry to examine relationships among seafloor geometry, ice sheet instability, and global climate.

I am thrilled to be participating in this exciting expedition and looking forward to expanding the scope of the Sedimentary Systems Research group into ice sheet and glacially influenced marine sedimentary processes as well as investigating paleoceanographic records of the Miocene and Pliocene.

I will be posting to this site throughout the expedition, so stay tuned for updates from the JOIDES Resolution.