georefid:2013-027514SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2013-0275142012-01-01publicationgeorefid:2013-027514Quaijtaal, WillemijnGhent University, Reasearch Unit Palaeontology, Ghent, BelgiumauthorSchouten, StefanRoyal Netherlands Institute for Sea Research, NetherlandsauthorDonders, TimmeGeological Survey of The Netherlands, NetherlandsauthorLouwye, Stephenauthor[International Geological Congress], [location varies], InternationalpublisherdocumentHardcopyIn: Anonymous, 34th international geological congress; abstracts342962The relatively warm climate of the Miocene reached peak values during the middle Miocene Climatic Optimum (MMCO; 17-14.5 Ma). After the MMCO, the global climate started cooling. This happened through several short-lived cooling events, represented by positive oxygen isotope excursions: the Mi-events. These disturbances can be associated with growth of the East Antarctic Ice Sheet and potentially Northern Hemisphere ice expansion. The causes and consequences of the Mi-events are not well constrained. For this reason we want to examine the role of the Gulf Stream in the cooling and subsequent warming of the Mi-events, since it is a possible mechanism to amplify regional changes in northwestern Europe. Integrated Ocean Drilling Program (IODP) Leg 307 recovered a high resolution record from the middle Miocene of the Porcupine Basin, offshore southwestern Ireland and therefore under the influence of the Gulf Stream. We have extracted well-preserved palynomorphs (mainly organic-walled dinoflagellate cysts, acritarchs, some pollen) and organic molecules for paleothermometry (e.g. TEX (sub 86) and U (super K') (sub 37) ) from core 1318B. With these proxies the development of the Mi-3 and Mi-4 events are reconstructed on high resolution, by assessing e.g. temperature, sea level, thermocline depth and productivity. First results indicate a pronounced cooling as recorded simultaneously in TEX (sub 86) , U (super k') (sub 37) and dinoflagellate cyst assemblages during Mi-4. The presented results will focus in detail on the phasing and rates of change in the reconstructed Mi-events.completedStratigraphyAtlantic OceanbiostratigraphyCenozoicExpedition 307Integrated Ocean Drilling Programmicrofossilsmiddle MioceneMiocenemiosporesNeogeneNorth AtlanticNortheast Atlanticpaleo-oceanographypaleoclimatologypaleoenvironmentpaleothermometrypalynomorphspollenPorcupine Seabightsea-level changesTertiaryurn:org.iodp:exp:307urnlargerWorkCitationcampaignEnglishgeoscientificInformation-11.4400-11.330051.220051.2700