georefid:2007-087836georefid:2007-087835SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2204/iodp.proc.302.101.20062004-01-01publicationgeorefid:2007-087836doi:10.2204/iodp.proc.302.101.2006Backman, JanStockholm University, Department of Geology and Geochemistry, Stockholm, SwedenauthorMoran, KathrynUniversity of Rhode Island, United StatesauthorMcInroy, DavidBritish Geological Survey, United KingdomauthorBrinkhuis, HenkUtrecht University, NetherlandsauthorClemens, StevenBrown University, United StatesauthorCronin, ThomasU. S. Geological Survey, United StatesauthorDickens, Gerald RoyRice University, United StatesauthorEynaud, FrederiqueUniversite de Bordeaux I, FranceauthorGattacceca, JeromeUniversity of Aix-Marseille III, FranceauthorJakobsson, MartinYamagata University, JapanauthorJordan, Richard W.University College London, United KingdomauthorKaminski, MichaelPolar Environmental Center, NorwayauthorKing, JohnBoston University, United StatesauthorKoc, NalanAlfred Wegener Institute for Polar and Marine Research, Federal Republic of GermanyauthorMartinez, Nahysa C.University of Michigan, United StatesauthorMatthiessen, JensKyushu University, JapanauthorMoore, Theodore C., Jr.University of Southampton, United KingdomauthorOnodera, JonaotaroUniversity of Aberdeen, United KingdomauthorO'Regan, MatthewUniversity of Padua, ItalyauthorPalike, HeikoJapan Agency for Marine-Earth Science and Technology, JapanauthorRea, BriceJames Madison University, United StatesauthorRio, DomenicoUniversity of Tsukuba, JapanauthorSakamoto, TatsuhikoTohoku University, JapanauthorSmith, David C.Institute of Geoscience, JapanauthorStein, RuedigerHokkaido University, JapanauthorSt. John, Kristen E. K.University of Rhode Island, United StatesauthorSuto, ItsukiBritish Geological Survey, United KingdomauthorSuzuki, NoritoshiUtrecht University, NetherlandsauthorTakahashi, KozoBrown University, United StatesauthorWatanabe, MahitoU. S. Geological Survey, United StatesauthorYamamoto, MasanobuUniversite de Bordeaux I, FranceauthorIODP Management International, Washington, DC, United StatespublisherdocumentDigitalIn: Backman, Jan, Moran, Kathryn, McInroy, David, Brinkhuis, Henk, Clemens, Steven, Cronin, Thomas, Dickens, Gerald Roy, Eynaud, Frederique, Gattacceca, Jerome, Jakobsson, Martin, Jordan, Richard W., Kaminski, Michael, King, John, Koc, Nalan, Martinez, Nahysa C., Mattiessen, Jens, Moore, Theodore C., Jr., Onodera, Jonaotaro, O'Regan, Matthew, Palike, Heiko, Rea, Brice, Rio, Domenico, Sakamoto, Tatsuhiko, Smith, David C., Stein, Ruediger, St. John, Kristen E. K., Suto, Itsuki, Suzuki, Noritoshi, Takahashi, Kozo, Watanabe, Mahito, Yamamoto, Masanobu, Proceedings of the Integrated Ocean Drilling Program; Arctic Coring Expedition (ACEX); Expedition 302 of the mission-specific drilling platform from and to Tromso, Norway; sites M0001-M0004; 7 August-13 September 2004302The first scientific drilling expedition to the central Arctic Ocean was completed in September 2004. Integrated Ocean Drilling Program Expedition 302, Arctic Coring Expedition (ACEX), recovered sediment cores to 428 meters below seafloor (mbsf) in water depths of approximately 1300 m, 250 km from the North Pole. Expedition 302's destination was the Lomonosov Ridge, hypothesized to be a sliver of continental crust that broke away from the Eurasian plate at approximately 56 Ma. As the ridge moved northward and subsided, marine sedimentation occurred and continues to the present, resulting in what was anticipated from seismic data to be a continuous paleoceanographic record. The elevation of the ridge above the surrounding abyssal plains ( approximately 3 km) ensured that sediments atop the ridge were free of turbidites. The primary scientific objective of Expedition 302 was to continuously recover this sediment record and to sample the underlying sedimentary bedrock by drilling and coring from a stationary drillship. The biggest challenge during Expedition 302 was maintaining the drillship's location while drilling and coring in 2-4 m thick sea ice that moved at speeds approaching 0.5 kt. Sea-ice cover over the Lomonosov Ridge moves with one of the two major Arctic sea-ice circulation systems, the Transpolar Drift, and responds locally to wind, tides, and currents. Until now, the high Arctic Ocean Basin, known as "mare incognitum" within the scientific community, had never before been deeply cored because of these challenging sea-ice conditions. Initial results reveal that biogenic carbonate is present only in the Holocene-Pleistocene interval. The upper 198 mbsf represents a relatively high sedimentation rate record of the past 18 m.y. and is composed of sediment with ice-rafted debris and dropstones, suggesting that ice-covered conditions extended at least this far back in time. Details of the ice type (e.g., iceberg versus sea ice), timing, and characteristics (e.g., perennial versus seasonal) await further study. A hiatus occurs at 193.13 mbsf, spanning a 25 m.y. interval from the early Miocene to the middle Eocene between approximately 18 Ma and 43 Ma. The sediment record during the middle Eocene is of dark, organic-rich biosiliceous composition. Isolated pebbles, interpreted as ice-rafted dropstones, are present down to 239 mbsf, well into this middle Eocene interval. Around the lower/middle Eocene boundary an abundance of Azolla spp. occurs, suggesting that a fresh and/or low-salinity surface water setting dominated the region during this time period. Although predrilling predictions based on geophysical data had placed the base of the sediment column at 50 Ma, drilling revealed that the uppermost Paleocene to lowermost Eocene boundary interval, well known as the Paleocene/Eocene Thermal Maximum (PETM), was recovered. During the PETM, the temperature of the Arctic Ocean surface waters exceeded 20 degrees C. Drilling during Expedition 302 also penetrated into the underlying sedimentary bedrock, revealing a shallow-water depositional environment of Late Cretaceous age.completedStratigraphyArctic Coring EXpeditionArctic OceanbiostratigraphyboreholesCenozoicchemostratigraphycoresCretaceousdensitydownhole methodsExpedition 302expeditionsgamma-ray spectrageochemistrygeophysical methodsgeophysical profilesgeophysical surveyshydrochemistryIntegrated Ocean Drilling ProgramIODP Site M0002IODP Site M0003IODP Site M0004lithostratigraphyLomonosov RidgeMesozoicphysical propertiespore watersedimentary rockssedimentationsedimentation ratesseismic methodsseismic profilesshear strengthspectrasurveystemperatureUpper Cretaceouswell logsurn:org.iodp:exp:302urnlargerWorkCitationcampaignurn:org.iodp:exp:302:site:M0002urnlargerWorkCitationstudyurn:org.iodp:exp:302urnlargerWorkCitationcampaignurn:org.iodp:exp:302:site:M0003urnlargerWorkCitationstudyurn:org.iodp:exp:302urnlargerWorkCitationcampaignurn:org.iodp:exp:302:site:M0004urnlargerWorkCitationstudyurn:org.iodp:exp:302urnlargerWorkCitationcampaignEnglishgeoscientificInformation136.1000139.330087.510087.5600application/pdfunknownSEDIS Publication Catalogue

ana.macario@awi.de

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