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June 13, 2014
JAMSTEC
Niigata University

Mediterranean Outflow and Its Global Significance
~ History of Mediterranean Outflow Water and Climate Changes ~

1. Overview

Integrated Ocean Drilling Program (IODP) Expedition 339, Mediterranean Outflow, was executed from November 2011 to January 2012 on board the research vessel JOIDES Resolution (figure 1). The expedition was led by Dr. F. Javier Hernández-Molina from the Royal Holloway University of London and Dr. Dorrik A.V. Stow from Heriot-Watt University, carrying an international team of 35 scientists from 14 countries, including Japan members (JAMSTEC, Institute of Geology and Geoinformation, Geological Survey of Japan (AIST), Niigata University and Hokkaido University), and recovered five kilometers of core samples from an area never before drilled along the Gulf of Cadiz and west off Portugal (figure 2).

These core samples collected showed sediments called “contourites (*1),” which is produced by a powerful cascade of “Mediterranean Outflow Water” spills out through the Strait of Gibraltar into the Atlantic Ocean. A detailed study revealed a history of the timing of Mediterranean outflow water activity spanning over five million years and how it is inextricably linked to climate changes and deep ocean circulation in the Atlantic Ocean.

These research results have been published in the online scientific journal Science, on June 13, 2014 (Japan time).

Title:Onset of Mediterranean Outflow into the North Atlantic

F. Javier Hernández-Molina1, Dorrik A.V. Stow2, Carlos A. Alvarez-Zarikian3, Gary Acton4, André Bahr5, Barbara Balestra6, Emmanuelle Ducassou7, Roger Flood8, José-Abel Flores9, Satoshi Furota10, Patrick Grunert11, David Hodell12, Francisco Jimenez-Espejo13, Jin Kyoung Kim14, Lawrence Krissek15, Junichiro Kuroda13, Baohua Li17, Estefania Llave18, Johanna Lofi19, Lucas Lourens20, Madeline Miller21, Futoshi Nanayama22, Naohisa Nishida22, Carl Richter23, Cristina Roque24, Hélder Pereira25, Maria Fernanda Sanchez Goñi7, Francisco J. Sierro9, Arun D. Singh27, Craig Sloss28, Yasuhiro Takashimizu29, Alexandrina Tzanova30, Antje Voelker24, Trevor Williams31 and Chuang Xuan32

1 Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK. 2 Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK. 3 International Ocean Discovery Program, Department of Oceanography, Texas A&M University, College Station, TX 77845, USA. 4 Department of Geography and Geology, Sam Houston State University, Huntsville, TX 77341, USA. 5 Institute of Geosciences, University of Frankfurt, 60438 Frankfurt, Germany. 6 Institute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA. 7 EPOC, Université de Bordeaux, 33615 Pessac Cedex, France. 8 School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA. 9 Departamento de Geología, Universidad de Salamanca, 3008 Salamanca, Spain. 10 Department of Natural History Sciences, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan. 11 Institute for Earth Sciences, University of Graz, A-8010 Graz, Austria. 12 Godwin Laboratory for Palaeoclimate Research, University of Cambridge, Cambridge CB2 3EQ, UK. 13 Department of Biogeochemistry, JAMSTEC, 237-0061 Yokosuka, Japan. 14 Korea Institute of Ocean Science & Technology, Ansan 426-744, Korea. 15 School of Earth Sciences, Ohio State University, Columbus, OH 43210, USA. 16 Institute for Frontier Research on Earth Evolution (IFREE), JAMSTEC, 2-15 Natsushima-Cho, Yokosuka-city, Kanagawa 237-0061, Japan. 17 Department of Micropalaeontology, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, P.R. China. 18 Instituto Geológico y Minero de España, Ríos Rosas 23, 28003 Madrid, Spain. 19 Géosciences Montpellier, Université Montpellier II, 34090 Montpellier, France, and Department of Geology, University of Leicester, Leicester LE1 7RH, UK. 20 Institute of Earth Sciences, Utrecht University, 3584 CD Utrecht, Netherlands. 21 Department of Mechanical Engineering, California Institute of Technology, Pasadena, CA 91125, USA. 22 Institute of Geology and Geoinformation, Geological Survey of Japan (AIST), Ibaraki 305-8567, Japan. 23 School of Geosciences, University of Louisiana, Lafayette, LA 70504, USA. 24 Divisão de Geologia e Georecursos Marinhos, IPMA, 1749-077 Lisboa, Portugal. 25 Grupo de Biologia e Geologia, Escola Secundária de Loulé, 8100-740 Loulé, Portugal. 26 École Pratique des Hautes Etudes, EPOC, Université de Bordeaux, 33615 Pessac, France. 27 Department of Geology, Banaras Hindu University, Varanasi 221005, India. 28 School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland 4001, Australia. 29 Department of Geology, Faculty of Education, Niigata University, Niigata 950-2181, Japan. 30 Department of Geological Sciences, Brown University, Providence, RI 02912, USA. 31 Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA. 32 Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, Southampton SO14 3ZH, UK.

*1. Contourites
A contourite is a sandy and muddy sedimentary deposit produced by thermohaline-induced deepwater bottom currents, following contours of ocean basin. The southwestern Iberian margin and the Gulf of Cadiz are under influence of strong current, the Mediterranean Outflow, along 500-1000m contours. Unlike clastic materials such as sand and mud that travel down the slop from top to bottom driven by gravity current (a flow that is driven by a density in fluids), contourites are influenced by bottom current. It is an interesting mechanism of transport different from gravity-driven current.

For more information about IODP Expedition 339, Mediterranean Outflow, visit
http://iodp.tamu.edu/scienceops/expeditions/mediterranean_outflow.html

Figure 1: Research vessel JOIDES Resolution arriving Lisbon after the IODP Expedition 339
(by Prof. F. Barriga, Portugal)

Figure 2: Regional water masses, major tectonic features, and Gulf of Cadiz CDS site locations sampled during IODP Expedition 339

Contacts:

JAMSTEC
(For this study)
Junichiro Kuroda, Chief Researcher
Department of Biogeochemistry
(For press release)
Kazushige Kikuchi, Manager,
Press Division, Public Relations Department
Niigata University
Naohiko Yamada, Public Relations Office
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