Integrated Ocean Drilling Program

Over the last 40 years, scientific ocean drilling initiatives from The Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) to the Integrated Ocean Drilling Program (IODP), have revolutionised our view of Earth history and global processes. These research programmes are widely considered to be models for international cooperation in multidisciplinary research and technological development. Their scientific and administrative structures evolved profoundly, and the evolution continues today with the Integrated Ocean Drilling Program (IODP). Started in October 2003, IODP was established with support from the United States(US) National Science Foundation and Japan’s Ministry of Education, Culture, Sports, Science, and Technology. The 17-member European Consortium on Ocean Research Drilling (ECORD), China’s Ministry of Science and Technology, and the Republic of Korea provide additional support.

The drilling vessel Vidar Viking near the North Pole during the Arctic Coring Expedition. ECORD/IODP

Investigating climate change

At the heart of the IODP is the Initial Science Plan (ISP), the fundamental blueprint to the scientific and technical objectives of IODP. Scientific emphasis is placed on three areas of investigations:

1) Environmental Change, Processes, and Effects: To understand global change, scientists must determine the mechanisms that drive climate events. IODP drills in equatorial and polar regions to acquire geological samples that yield critical information about past extreme climates. Such samples provide indispensable context for evaluating contemporary inputs to the environment, and creating climate models that aid in projecting future climate conditions.

2) The Deep Biosphere and Subseafloor Ocean: The legacy Ocean Drilling Program provided the first evidence of abundant, diverse microbial activity deep within ocean crust. This discovery encouraged microbiologists, biogeochemists and geologists to expand subseafloor explorations of sediment and rock lithology, organic carbon content, rates of sediment accumulation and depth and how they influence the ecosystem. Global mapping of subseafloor biological communities is also critical to fully understanding this ecosystem.

3) Solid Earth Cycles and Geodynamics: Continental break-up and its role in sedimentary basin formation, volcanism, the formation of rifted margins and oceanic plateaux, seafloor spreading, and the generation of earthquakes and tsunamis comprise this major area of focus. Scientists aim to learn more about the history and mechanisms of these colossal events and what the data may indicate to future generations of Earth dwellers.

	The ACEX convoy heading towards the Lomonosov Ridge. ECORD/IODP

Clues in sediment

During the first phase of IODP operations, four drilling expeditions focused on climate change investigations. Perhaps the most significant of these was the Arctic Coring Expedition (ACEX) near the North Pole. The expedition recovered the first extensive series of sediments that yielded prehistoric climate records of the Arctic Ocean.

Navigating thick and relentless ice floes, the research team strategically managed three icebreakers, one equipped with a drill rig. A complete geological sediment record was recovered from the Lomonosov Ridge, in water approximately 1,000 metres deep. These records provide evidence that the Arctic climate was extremely warm and unusually wet, and that the Artic Ocean was ice-free up to the time the last massive amounts of greenhouse gases were released into the Earth’s atmosphere – a period calculated to have occurred 55 million years ago, known as the Paleocene/Eocene thermal maximum, or PETM.

IODP uses multiple platforms to conduct sub-seafloor investigations:

• A riserless platform, provided by the US, is managed by an alliance of three institutions (the Consortium of Ocean Leadership,Texas A & M University, and Lamont-Doherty Earth Observatory of Columbia University). The Texas-based Gulf Coast Core Repository archives sediment cores retrieved by any of the IODP platforms in the following regions: the Pacific Ocean (Pacific plate east of western boundary); the Caribbean Sea and Gulf of Mexico and the Southern Oceans (S of 60º except Kerguelan Plateau)

• Riser platform operations are carried out aboard the Chikyu, a state-of-the-art research drilling vessel provided by Japan and managed by Japan’s Center for Deep Earth Exploration (CDEX). Drilling operations are performed in cooperation with the Center for Advanced Marine Core Research at Kochi University, which contributes to sediment core processing and which archives cores collected from the Pacific Ocean (west of western boundary of Pacific plate); the Indian Ocean (N of 60ºS), all of the Kerguelan Plateau and the Bering Sea.

• Mission-specific drilling operations are conducted by ECORD (ECORD Science Operator – ESO), a collaboration between the British Geological Survey, the University of Bremen – Germany, and the European Petrophysics Consortium. ESO works in cooperation with the Bremen Core Repository, which archives sediment cores from the Atlantic and Arctic Oceans, north of the Bering Strait.

Drilling proposals originate with science proponents, often faculty members of prominent academic institutions; scientists who specialise in geology, geophysics, sedimentology, paleontology, paleoceanography, or seismology. A drilling proposal, once submitted to IODP, is carefully nurtured and evaluated to ensure its smooth movement through a Science Advisory Structure, a group of oversight panels and committees that nurture and enhance proposals until they can be ranked and prioritised for scheduling. Twice a year IODP accepts and reviews drilling proposals.

W: www.iodp.org