Down to the Core: Craig Fulthorpe Co-Leads Expedition to Canterbury Basin
Filed under: Discovery,News & Resources,Scientific Ocean Drilling
(Click to enlarge) Scientists on IODP Leg 317 collected core samples near New Zealand to investigate ancient sea level, ocean circulation and climate. (Credit: William Crawford, IODP/TAMU)
Craig Fulthorpe was a grad student when his advisor walked into his office and asked if he would like to be part of the first scientific expedition organized by the Ocean Drilling Program (ODP). As luck would have it, a sedimentologist who had been scheduled to be on that cruise had to back out just weeks before it set sail for the Bahamas and they needed a replacement fast. Fulthorpe said yes. It changed his career.
(From Jackson School of Geosciences / by Marc Airhart) – “Going on ODP Leg 101 introduced me to this whole community in a way that might not have happened otherwise,” he says. “It was a great opportunity. It was my first extended time at sea.”
That was in 1985. The ODP was an international partnership that had just begun to explore Earth’s history and structure as recorded in the ocean basins. They had recently converted an oil exploration ship into a floating laboratory and renamed it the JOIDES Resolution. The first expedition was designed to study the origin and evolution of the Bahamas carbonate platform.
“As a young scientist, it was a great learning experience,” he says. “I got to work with more senior people and got real insight into the way large scale science is done.”
Today, Fulthorpe is a senior research scientist at the Institute for Geophysics, which itself has a long and storied history with the three major international scientific ocean drilling programs. He works just a few doors down from Jamie Austin, another ocean drilling veteran he met on that first ODP cruise when Austin was co-chief scientist. Fulthorpe came to the Institute early in his career and never left.
In January 2010, he returned from his fourth cruise through ODP and its successor, the Integrated Ocean Drilling Program (IODP). This time he was co-chief scientist, along with Koichi Hoyanagi from Shinshu University in Japan, on an expedition to Canterbury Basin off the eastern coast of New Zealand’s South Island.
Down Under
Seafloor sediments along continental margins record changes in global sea level going back millions of years. This record has the potential to help scientists forecast how sea level might change as a response to the current period of rapid global warming. Unfortunately, the record isn’t so easy to read. Seafloor sediments are also affected by local tectonic, sedimentary, and oceanographic processes. Fulthorpe’s cruise to Canterbury Basin was designed to help untangle those confounding effects.
Canterbury Basin is ideal for this work because seafloor sediments there record information about climate and sea level in exquisite detail going back 35 million years. An uplifting mountain chain nearby and strong ocean currents ensure a large quantity of sediment flows into the basin.
Canterbury Basin is one of several sites around the world sampled by IODP scientists to study global sea level changes, primarily during Earth’s “Icehouse” period (last 30-40 million years), when sea level was largely controlled by changes in the volume of polar ice sheets. Data from both the Canterbury Basin expedition and an earlier New Jersey shelf expedition will be integrated to provide a better understanding of global trends in sea level over time.
Craig Fulthorpe was co-chief scientist for IODP Leg 317. (Credit: William Crawford, IODP/TAMU)
Canterbury Basin is one of several sites around the world sampled by IODP scientists to study global sea level changes during Earth’s “Icehouse” period (10 to 12 million years ago), when sea level was largely controlled by changes in glaciation at the poles. Data from both the Canterbury Basin expedition and an earlier New Jersey shelf expedition will be integrated to provide a better understanding of global trends in sea level over time.
Drilling in the Canterbury Basin also allowed the scientists to investigate what happened when the seaway between Australia and Antarctica opened up around 30 million years ago, initiating a strong ocean circulation pattern. This major event in Earth’s history is recorded in the Marshall Paraconformity, a gap in the rock record indicating an extended period of non-deposition. In core samples, it occurs as a rubble layer between two layers of white limestone.
Fulthorpe says understanding the past helps scientists know what Earth’s systems are capable of in the future. For example, scientists studying sediment and ice cores have been surprised to find how rapidly and dramatically Earth’s climate can change.
“If you aren’t aware that very rapid change can happen, you can’t factor it into future predictions,” he says. “You have to be aware of everything the Earth can throw at you to address what might happen in the future.”
Gone Fishing
The JOIDES Resolution is 143 meters (470 feet) long and holds up to 125 people, usually half support crew and half scientists and technicians. The ship operates 24 hours a day with crew members alternating in 12 hour shifts. On a typical two month trip with a full ship, the galley crew stocks 12,000 pounds of fish, 10,000 eggs, 5,000 pounds of fresh fruit and vegetables, 1,000 gallons of milk, and 1,000 pounds of flour.
The ship is operated by the U.S. Implementing Organization, made up of the Consortium for Ocean Leadership, Texas A&M University and Lamont-Doherty Earth Observatory with funding from the National Science Foundation (NSF). The JOIDES part of the name comes from the now defunct Joint Oceanographic Institutions for Deep Earth Sampling.
(Click to enlarge) Team members plant colored flags in a core to claim samples. Stacie Blair, paleontologist from Florida State University, collects sediment samples from a core. (Credit: William Crawford, IODP/TAMU)
Fulthorpe says a few things have changed on the JOIDES Resolution in 25 years. His first time around, there was no telephone. And of course, no email. You could write and receive paper letters thanks to occasional helicopter visits from administrators and dignitaries. Or you could establish a phone patch with the help of a ham radio operator, but it was complicated.
“I made one phone call,” he says. “It was very awkward. You had people listening in on your end and an operator listening on the other end.”
For several weeks at sea, there was little news from the outside world or connection with friends and family far away. It could be isolating, but the upside was that working on the ship in the old days was intensely focused on the job at hand, scientists working seven days a week, pausing for little more than sleeping and eating.
Today, there are satellite phones that let you make calls at the same cost as it would be to call from College Station, Texas, as well as continuous email and Internet access. It’s true, says Fulthorpe, you don’t feel so isolated. Yet there are a lot more distractions. Your office work and home life follow you around the world. People back home don’t understand that you might have a hard time replying to an email within an hour or two.
Smashing Records
For two months beginning in November 2009, Fulthorpe and his team drilled four sites in the seafloor and recovered sediment cores going back as far as 35 million years. The Marshall Paraconformity turned out to be deeper than initially thought, so they had to ask for permission to drill deeper. They ended up drilling the deepest hole on a single expedition in the history of scientific ocean drilling (nearly 2 kilometers).
(Click to enlarge) Searching for a previously elusive gap in the core record called the Marshall Paraconformity, the team drilled the deepest hole on a single expedition in the history of scientific ocean drilling (nearly 2 kilometers). (Credit William Crawford, IODP/TAMU)
When cores are brought up from the seafloor they can be either moist and pliable like tubes of modeling clay or solid cylinders of rock. Once on board, they’re sliced in half. One part goes into a refrigerated archive. Team members look over the other half and stick colored flags in it claiming samples for themselves or for shore-based scientists. Some samples they analyze in onboard labs, others they have shipped back to their home institutions for more intensive analysis. Scientific results from their various projects will be published gradually over the next couple of years.
Fulthorpe’s main role was to tie the sediments they recovered back to seismic data collected before the expedition. In addition to sedimentologists like Fulthorpe, the team also included experts in paleomagnetics, geochemistry, physical properties of sediments, biostratigraphy, and microbiology.
A second record was broken when the team recovered sediment from the shallowest water site ever drilled for science by the JOIDES Resolution (85 meters water depth). To drill deep holes in the seafloor, the ship uses a Dynamic Positioning System (DP) to remain stationary over the hole. A special computer collects positioning information from two GPS receivers and one hydro acoustic beacon on the seafloor to determine real time position and then uses that information to control 12 powerful thrusters and 2 propellers. Maintaining an exact position is especially difficult in shallow water because the distance the ship can safely move off position is a percentage of water depth.
A third record was broken when the team recovered the deepest samples for microbiological analysis collected during scientific ocean drilling (nearly 2 kilometers). These samples could potentially extend the maximum known depth of habitable sediments. The team’s lone microbiologist, Maria-Cristina Ciobanu from the European Institute for Marine Studies at the University of Brest, France, is still analyzing these samples.
The team did have some challenges with boreholes collapsing and less than complete recovery of sediments, which is typical of working in that kind of environment. But Fulthorpe says the expedition went very well from a research perspective. The team achieved all their major scientific objectives, the sediments were not difficult to drill, and the weather was good. He says just as important is what this kind of mission provides to early career scientists.
“It’s great for getting them introduced to the community, making contacts, and forming collaborations,” he says. “I don’t know of any other earth science program as effective in that way.”
