Now showing items 687-706 of 1092

    • Observations of Li isotopic variations in the Trinity Ophiolite : evidence for isotopic fractionation by diffusion during mantle melting 

      Lundstrom, Craig C.; Chaussidon, Marc; Hsui, Albert T.; Kelemen, Peter B.; Zimmerman, Mark (2004-08-10)
      The Trinity peridotite (northern CA) contains numerous lithologic sequences consisting of dunite to harzburgite to spinel lherzolite to plagioclase lherzolite. Previous workers have documented geochemical gradients in these ...
    • Observed and modeled Greenland ice sheet snow accumulation, 1958-2003, and links with regional climate forcing 

      Hanna, Edward; McConnell, Joseph R.; Das, Sarah B.; Cappelen, John; Stephens, Ag (American Meteorological Society, 2006-02-01)
      Annual and monthly snow accumulation for the Greenland Ice Sheet was derived from ECMWF forecasts [mainly 40-yr ECMWR Re-Analysis (ERA-40)] and further meteorological modeling. Modeled accumulation was validated using 58 ...
    • Observing the Galápagos–EUC interaction : insights and challenges 

      Karnauskas, Kristopher B.; Murtugudde, Raghu; Busalacchi, Antonio J. (American Meteorological Society, 2010-12)
      Although sustained observations yield a description of the mean equatorial current system from the western Pacific to the eastern terminus of the Tropical Atmosphere Ocean (TAO) array, a comprehensive observational dataset ...
    • Ocean acidification not likely to affect the survival and fitness of two temperate benthic foraminiferal species : results from culture experiments 

      McIntyre-Wressnig, Anna; Bernhard, Joan M.; Wit, Johannes C.; McCorkle, Daniel C. (2014-10)
      Specimens of Bolivina argentea and Bulimina marginata, two widely distributed temperate benthic foraminiferal species, were cultured at constant temperature and controlled pCO2 (ambient, 1000 ppmv, and 2000 ppmv) for six ...
    • Ocean bottom seismic scattering 

      Dougherty, Martin E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1989-08)
      Seismic studies of the oceanic crust, both experimental and theoretical, often assume a flat seafloor and laterally homogeneous crust. This is done regardless of the appearance in seismic data of obvious effects due to ...
    • Ocean Bottom Seismometer Augmentation in the North Pacific (OBSANP) - cruise report 

      Stephen, Ralph A.; Worcester, Peter F.; Udovydchenkov, Ilya A.; Aaron, Ernie; Bolmer, S. Thompson; Carey, Scott; McPeak, Sean P.; Swift, Stephen A.; Dzieciuch, Matthew A. (Woods Hole Oceanographic Institution, 2014-12)
      The Ocean Bottom Seismometer Augmentation in the North Pacific Experiment (OBSANP, June-July, 2013, R/V Melville) addresses the coherence and depth dependence of deep-water ambient noise and signals. During the 2004 NPAL ...
    • Ocean Bottom Seismometer Augmentation of the Philippine Sea Experiment (OBSAPS) cruise report 

      Stephen, Ralph A.; Kemp, John N.; McPeak, Sean P.; Bolmer, S. Thompson; Carey, Scott; Aaron, Ernie; Campbell, Richard L.; Moskovitz, Brianne; Calderwood, John; Cohen, Ben; Worcester, Peter F.; Dzieciuch, Matthew A. (Woods Hole Oceanographic Institution, 2011-09)
      The Ocean Bottom Seismometer Augmentation to the Philippine Sea Experiment (OBSAPS, April-May, 2011, R/V Revelle) addresses the coherence and depth dependence of deep-water ambient noise and signals. During the 2004 NPAL ...
    • Ocean climate variability in the eastern North Atlantic during interglacial marine isotope stage 11 : a partial analogue to the Holocene? 

      de Abreu, Lucia; Abrantes, Fatima G.; Shackleton, Nicholas J.; Tzedakis, Polychronis C.; McManus, Jerry F.; Oppo, Delia W.; Hall, Michael A. (American Geophysical Union, 2005-08-30)
      Similar orbital geometry and greenhouse gas concentrations during marine isotope stage 11 (MIS 11) and the Holocene make stage 11 perhaps the best geological analogue period for the natural development of the present ...
    • Ocean rises are products of variable mantle composition, temperature and focused melting 

      Dick, Henry J. B.; Zhou, Huaiyang (2014-12)
      Ocean ridges, where Earth’s tectonic plates are pulled apart, vary from more than 5- km depth in the Arctic to 750 m above sea level in Iceland. This huge relief is generally attributed to mantle plumes underlying mantle ...
    • Ocean Seismic Network Pilot Experiment 

      Stephen, Ralph A.; Spiess, Fred N.; Collins, John A.; Hildebrand, John A.; Orcutt, John A.; Peal, Kenneth R.; Vernon, Frank L.; Wooding, Frank B. (2003-10-31)
      The primary goal of the Ocean Seismic Network Pilot Experiment (OSNPE) was to learn how to make high quality broadband seismic measurements on the ocean bottom in preparation for a permanent ocean seismic network. The ...
    • Oceanic evidence of climate change in southern Australia over the last three centuries 

      Thresher, Ronald E.; Rintoul, Stephen R.; Koslow, J. Anthony; Weidman, Christopher R.; Adkins, Jess F.; Proctor, Craig (American Geophysical Union, 2004-04-13)
      Chemical analysis of deepwater octocorals collected at 1000 m depth off southern Australia indicates long-term cooling, beginning in the mid-18th century. This cooling appears to reflect shoaling of isotherms along the ...
    • Oceanic lithosphere magnetization : marine magnetic investigations of crustal accretion and tectonic processes in mid-ocean ridge environments 

      Williams, Clare M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)
      The origin of symmetric alternating magnetic polarity stripes on the seafloor is investigated in two marine environments; along the ridge axis of the fast spreading East Pacific Rise (EPR) (9º 25’-9º 55’N) and at Kane ...
    • Oceanography : oxygen and climate dynamics 

      Doney, Scott C.; Karnauskas, Kristopher B. (Nature Publishing Group, 2014-09)
      Low oxygen levels in tropical oceans shape marine ecosystems and biogeochemistry with climate change expected to expand these regions. Now, a study indicates that regional dynamics control trop ...
    • Olivine friction at the base of oceanic seismogenic zones 

      Boettcher, Margaret S.; Hirth, Greg; Evans, Brian (American Geophysical Union, 2007-01-31)
      We investigate the strength and frictional behavior of olivine aggregates at temperatures and effective confining pressures similar to those at the base of the seismogenic zone on a typical ridge transform fault. Triaxial ...
    • On a neck, on a spit : controls on the shape of free spits 

      Ashton, Andrew; Nienhuis, Jaap; Ells, Kenneth (Copernicus Publications on behalf of the European Geosciences Union, 2016-02-03)
      We investigate the controls upon the shape of freely extending spits using a one-contour-line model of shoreline evolution. In contrast to existing frameworks that suggest that spits are oriented in the direction of ...
    • On the Abyssal circulation in the glacial Atlantic 

      Marchal, Olivier; Curry, William B. (American Meteorological Society, 2008-09)
      An inverse method is used to evaluate the information contained in sediment data for the Atlantic basin during the Last Glacial Maximum (defined here as the time interval 18–21 kyr before present). The data being considered ...
    • On the movements of the North Atlantic Subpolar Front in the preinstrumental past 

      Marchal, Olivier; Waelbroeck, Claire; Colin de Verdiere, Alain (American Meteorological Society, 2016-02-19)
      Three sediment records of sea surface temperature (SST) are analyzed that originate from distant locations in the North Atlantic, have centennial-to-multicentennial resolution, are based on the same reconstruction method ...
    • On the observability of oceanic gyres 

      Marchal, Olivier (American Meteorological Society, 2014-09)
      This study examines the observability of a stratified ocean in a square flat basin on a midlatitude beta plane. Here, “observability” means the ability to establish, in a finite interval of time, the time-dependent ocean ...
    • ONR seafloor natural laboratories on slow- and fast-spreading mid-ocean ridges 

      Tucholke, Brian E.; Macdonald, Ken C.; Fox, Paul J. (American Geophysical Union, 1991-06-18)
      Long-term Natural Laboratories for in-depth studies of the seafloor at both a slowspreading (<30 mm/yr) and a fast-spreading (>60 mm/yr) mid-ocean ridge are being established by the Office of Naval Research. The two Natural ...
    • Optimizing a microwave gas ion source for continuous-flow accelerator mass spectrometry 

      von Reden, Karl F.; Roberts, Mark L.; Burton, Joshua R.; Beaupre, Steven R. (2011-09)
      A 2.45 GHz microwave ion source coupled with a magnesium charge exchange canal (CxC) has been successfully adapted to a large acceptance radiocarbon accelerator mass spectrometry system at the National Ocean Sciences AMS ...