The Opening of the Arctic-Atlantic Gateway: Tectonic, Oceanographic and Climatic Dynamics - an IODP Initiative

Tuesday, 16 December 2014
Wolfram H. Geissler1, Jochen Knies2, Tove Nielsen3, Carmen Gaina4, Jens J Matthiessen1, Catalina Gebhardt1, Volkmar Damm5, Matthias Forwick6, Berit Oline Hjelstuen7, John R Hopper3, Katrine Husum8, Jan Sverre Laberg6, Wolfram Kuerschner9, Caterina Morigi10, Michael Schreck11, Aradhna K. Tripati12, Christoph Martin Vogt13, Michele Rebesco14, Seung-il Nam15, Anders E Carlson16, Stijn De Schepper17, Renata Lucchi14, Rune Mattingsdal18, Wilfried Jokat1 and Ruediger H Stein1, (1)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (2)Geological Survey of Norway, Trondheim, Norway, (3)The National Geological Survey of Denmark and Greenland, København, Denmark, (4)University of Oslo, Centre for Earth Evolution and Dynamics (CEED), Oslo, Norway, (5)BGR Hannover, Hannover, Germany, (6)University of Tromsø, Tromsø, Norway, (7)University of Bergen, Department of Geology, Bergen, Norway, (8)Norwegian Polar Institute, Tromsø, Norway, (9)University of Oslo, Oslo, Norway, (10)University of Pisa, Department of Earth Sciences, Pisa, Italy, (11)KOPRI Korea Polar Research Institute, Arctic Research Centre, Incheon, South Korea, (12)University of California Los Angeles, Los Angeles, CA, United States, (13)University of Bremen, Bremen, Germany, (14)National Institute of Oceanography and Applied Geophysics OGS, Trieste, Italy, (15)KOPRI Korea Polar Research Institute, Incheon, South Korea, (16)COAS, Corvallis, OR, United States, (17)Bjerknes Centre for Climate Research, Bergen, Norway, (18)Norwegian Petroleum Directorate, Harstad, Norway
The modern polar cryosphere reflects an extreme climate state with profound temperature gradients towards high-latitudes. It developed in association with stepwise Cenozoic cooling, beginning with ephemeral glaciations and the appearance of sea ice in the late middle Eocene. The polar ocean gateways played a pivotal role in changing the polar and global climate, along with declining greenhouse gas levels. The opening of the Drake Passage finalized the oceanographic isolation of Antarctica, some 40 Ma ago. The Arctic Ocean was an isolated basin until the early Miocene when rifting and subsequent sea-floor spreading started between Greenland and Svalbard, initiating the opening of the Fram Strait / Arctic-Atlantic Gateway (AAG). Although this gateway is known to be important in Earth’s past and modern climate, little is known about its Cenozoic development. However, the opening history and AAG’s consecutive widening and deepening must have had a strong impact on circulation and water mass exchange between the Arctic Ocean and the North Atlantic.

To study the AAG’s complete history, ocean drilling at two primary sites and one alternate site located between 73°N and 78°N are proposed. These sites will provide unprecedented sedimentary records that will unveil (1) the history of shallow-water exchange between the Arctic Ocean and the North Atlantic, and (2) the development of the AAG to a deep-water connection and its influence on the global climate system.

The specific overarching goals of our proposal are to study:

• the influence of distinct tectonic events in the development of the AAG and the formation of deep water passage on the North Atlantic and Arctic paleoceanography, and

• the role of the AAG in the climate transition from the Paleogene greenhouse to the Neogene icehouse for the long-term (~50 Ma) climate history of the northern North Atlantic.