Description: 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. Indeed, 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 Arctic-Atlantic gateway's complete history, ocean drilling (IODP Full 934) at four (primary) sites 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.

Description: 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 in the Boreas Basin and along the East Greenland continental margin 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: (1) 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 (2) 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. Getting a continuous record of the Cenozoic sedimentary succession that recorded the evolution of the Arctic-North Atlantic horizontal and vertical motions, and land and water connections will also help better understanding the post-breakup evolution of the NE Atlantic conjugate margins and associated sedimentary basins.

Description: 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 in the Boreas Basin and along the East Greenland continental margin 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: (1) 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 (2) 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. Getting a continuous record of the Cenozoic sedimentary succession that recorded the evolution of the Arctic-North Atlantic horizontal and vertical motions, and land and water connections will also help better understanding the post-breakup evolution of the NE Atlantic conjugate margins and associated sedimentary basins.

Description: 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 in the Boreas Basin and along the East Greenland continental margin 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: (1) 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 (2) 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. Getting a continuous record of the Cenozoic sedimentary succession that recorded the evolution of the Arctic-North Atlantic horizontal and vertical motions, and land and water connections will also help better understanding the post-breakup evolution of the NE Atlantic conjugate margins and associated sedimentary basins.

Description: During the "RV Polarstem"-Expedition ARK VIII/2 sediment samples were obtained at the continentalslope of NW-Spitsbergen. Detailed sedimentological and geochemical analysis were carriedout at two undisturbed box cores (PS2122-1GKG, PS2123-2GKG) as well as two gravity cores(PS2122-1SL, PS2123-2SL). The following parameters were deterrnined: Organic carbon, nitrogenand carbonate contents, hydrogen index, stable isotopes, ice rafted debris, grain-size distribution andbiogenic opal. The main objective of this study was the reconstruction of paleoenvironmental changes off thenorthwest coast of Spitsbergen during the last glacial/interglacial-cycle, i.e., during the last about128.000 years.The results of the investigations can be summarized as follows:- During isotope stage 1 (Holocene) and 5.5 (Eemian Interglacial), light stable isotopes (8180: 3,4-2%0; 8BC: 0,26-0,5 %0), increased bioturbation, high content of planktonic foraminifera andbiogenic opal and low quantity of ice-rafted material, indicate seasonally ice-free conditions alongthe northwest coast due to the int1uence of the Westspitsbergen Current.- Additionally, the sediment characteristics of the middle of isotope stage 2 (Last Glacial Maximum)and at the end of stage 3 confirms an inflow of warmer Atlantic water. The highest production ofplanktonic and benthic foraminifera (N. pachyderma sin., Cassidulina teretis) (CaC03: 10 %) mayret1ect the expansion of the "Whalers Bay"-Polynya as a result of the int1uence of the WestspitsbergenCurrent. Presumably, occasionally open-ice conditions provide sufficient precipitation to buildupthe Svalbard/Barents Ice Sheet.- The time intervals for the glacier advances on Svalbard given by Mangerud et al. (1992), can becorrelated with increased accumulation of ice-rafted material in the sediments at the northwest coastof Spitsbergen. Especially during isotope stage 4 and at the beginning of the Last Glacial Maximum(isotope stage 2), a drastically increased supply of coarse terrigenous material occurs. The highaccumulation rate (0,18-0,21 g/cm2jky) of terrigenous organic carbon is indicated by high C/Nratios(until 16) and low hydrogen index (50 mg-HC/gC). In constrast to deep sea sediments in theFram-Strait (Hebbeln 1992), the glacier advance between 118.000 and 108.000 years B.P. ist documented in the continental slope sediments.- At the end of the Weichselian ice age, the deglaciation at the northwest coast starts with a typicalmelt-water signal in the stables isotope record (8180: 3,5 %0; 813C: -0,16 %0) and high contents ofgravel (6-13 %). The signal can be assigned to an event at the westcoast of Spitsbergen (core NP9039), dated to 14.500 years B.P. (Andersen et al. 1993).