International Ocean Discovery Program (IODP) Expedition 397
Iberian Margin Paleoclimate

As a part of International Ocean Discovery Program (IODP, *1), a research cruise of the JOIDES Resolution (*2) is set to begin on 11 October 2022 as IODP Expedition 397 program (see the addendum). The purpose of this cruise is to understand the natural variability of the North Atlantic climate (before human impact) at unprecedented temporal resolution back through the Pliocene Epoch (last 5 million years).

A total of 25 researchers from Australia, China, Germany, France, India, Japan, Portugal, Spain, United Kingdom, and the United States are scheduled to join the research cruise, including two Japanese onboard participants.

Addendum

Iberian Margin Paleoclimate

1. Schedule (local time)
  IODP Expedition 397

※ The schedule may change depending upon the condition/inflences of COVID-19, the progress in sailing preparations, weather conditions, and/or research activities.

2. Scientists scheduled to participate from Japan

3. Research Purposes and Objectives
International Ocean Discovery Program (IODP) Expedition 397 will take place off the Iberia Peninsula where rapidly accumulating sediments contain a high-fidelity record of past climate change. Most sediment in the deep sea accumulates at rates of 1–2 cm every thousand years, whereas sediments in the targeted area accumulate ten times faster (10–20 cm every thousand years), making it possible for climate events to be resolved on timescales of hundreds (centennial) to thousands (millennial) of years.

Previous studies of marine sediment sequences from this area have demonstrated that the sedimentary profiles can be correlated precisely to the polar ice cores in Greenland and Antarctica. Moreover, the narrow continental shelf (ocean bottom at a water depth of 0–200 m) permits a rapid delivery of material from the nearby continent to the deep-sea environment, thereby providing a record of European terrestrial climate at the same location. During Integrated Ocean Drilling Program Expedition 339, Site U1385 was drilled in the same location to 155.9 m below the seafloor. The study of Site U1385 has confirmed the continuity of high sedimentation rates (10–20 cm per thousand years) for the last 1.45 million years and the uniqueness of the detailed marine-ice-terrestrial linkages possible at this location.

IODP Expedition 397 will extend this remarkable sediment archive back to 3–5 million years ago through the geologic periods known as the Quaternary and Pliocene. Furthermore, we will drill additional sequences in water depths of 1,304–4,686 m below sea level. This depth transect is designed to study the past variability of all the water masses that fill the eastern North Atlantic Basin. Of particular interest are the behavior of the deeper water masses and their role in carbon storage and its effect on atmospheric carbon dioxide. The sediment cores recovered during IODP Expedition 397 will be important for studying the role that millennial climate variability has played in the waxing and waning of the great Northern Hemisphere ice sheets during the last 3 million years.

The fidelity of the climate signals preserved in the sediments to be drilled during IODP Expedition 397 will provide the greatest possible potential to reconstruct the natural variability of the North Atlantic climate (before human impact) at unprecedented temporal resolution back through the Pliocene (last 5 million years).

Hodell, D.A., Abrantes, F., and Alvarez Zarikian, C.A., 2022. Expedition 397 Scientific Prospectus: Iberian Margin Paleoclimate. International Ocean Discovery Program. https://doi.org/10.14379/iodp.sp.397.2022

Figure　Locations of drilling sites. The orange circles represent the primary target sites (orange circles). The purple rectangles indicate departure port (Lisbon, Portugal) and return port (Tarragona, Spain).

*Figure is cited from the IODP website with partial modification.
IODP JRSO・Expeditions・Iberian Margin Paleoclimate
https://iodp.tamu.edu/scienceops/expeditions/iberian_margin_paleoclimate.html
http://iodp.tamu.edu/scienceops/precruise/iberia/771-Full2_Hodell_web.pdf
http://iodp.tamu.edu/scienceops/precruise/iberia/771-Add_Hodell_web.pdf
http://iodp.tamu.edu/scienceops/precruise/iberia/771-Add2_Hodell_web.pdf
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