North Atlantic ODP982 Pliocene Alkenone SST Reconstruction Lawrence, K.T.; Herbert, T.D.; Brown, C.M.; Raymo, M.E.; Haywood, A.M. Lawrence, K.T. Herbert, T.D. Brown, C.M. Raymo, M.E. Haywood, A.M. Sea Surface Temperature Reconstruction earth science/paleoclimate/climate reconstructions|paleoceanography (sea surface temperature,alkenone unsaturation index,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,Prahl et al. 1988 calibration) earth science/paleoclimate/paleoceanography (age,null,null,calendar year before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (alkenone unsaturation index Uk37 prime,null,null,dimensionless,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (ODP 982>LATITUDE 57.517>LONGITUDE -15.8665) We provide the first continuous, orbital-resolution sea surface temperature (SST) record from the high-latitude North Atlantic, a region critical to understanding the origin of the Plio-Pleistocene ice ages and proximal to regions that became frequently glaciated after ~2.7 Ma. We analyzed sediments from Ocean Drilling Program Site 982 over the last 4 Ma for their alkenone unsaturation index and compared this surface water signal to a benthic d18O record obtained from the same section. We find that while ocean surface temperatures were significantly warmer (~6°C) than modern temperatures during the early Pliocene, they were also as variable as those during the late Pleistocene, a surprising result in light of the subdued variance of oxygen isotopic time series during the interval of 3-5 Ma. We propose two possible explanations for the high orbital-scale SST variability observed: either that a strong, high-latitude feedback mechanism not involving large continental ice sheets alternately cooled and warmed a broad region of the northern high latitudes or that by virtue of its location near the northern margin of the North Atlantic Drift, the site was unusually sensitive to obliquity-driven climate shifts. On supraorbital time scales, a strong, sustained cooling of North Atlantic SSTs (~4.5°C) occurred from 3.5 to 2.5 Ma and was followed by an interval of more modest cooling (an additional 1.5°C) from 2.5 Ma to the present. Evolutionary orbital-scale phase relationships between North Atlantic SST and benthic d18O show that SST began to lead d18O significantly coincident with the onset of strong cooling at Site 982 (~3.5 Ma). We speculate that these changes were related to the growth and subsequent persistence of a Greenland ice sheet of approximately modern size through interglacial states. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Lawrence, K.T. Investigator : Herbert, T.D. Investigator : Brown, C.M. Investigator : Raymo, M.E. Investigator : Haywood, A.M. 2009-07-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/8624 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/odp982-l-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/lawrence2009 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/odp982-l-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/lawrence2009 English https://www.ncdc.noaa.gov/paleo/study/8624 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/odp982-l-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/lawrence2009 Lawrence, K.T., T.D. Herbert, C.M. Brown, M.E. Raymo, and A.M. Haywood2009High-amplitude variations in North Atlantic sea surface temperature during the early Pliocene warm periodPaleoceanography10.1029/2008PA001669 START YEAR: 4012228 14C yr BP * END YEAR: 0 14C yr BP -15.8665 57.517 -15.8665 57.517