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  • Data  (4)
  • Ocean Drilling Program; ODP  (3)
  • 181-1123; AGE; COMPCORE; Composite Core; interpolated; Joides Resolution; Leg181; Magnesium/Calcium ratio; Magnesium/Calcium ratio, maximum; Magnesium/Calcium ratio, minimum; Normalized; Ocean Drilling Program; ODP; South Pacific Ocean  (1)
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  • Data  (4)
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Keywords
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  • 1
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    Mg/Ca and stable oxygen isotope ratios of Uvigerina spp. from the Southern Ocean (2010)
    PANGAEA
    In:  Supplement to: Elderfield, Henry; Greaves, Mervyn; Barker, S; Hall, Ian R; Tripati, Aradhna K; Ferretti, Patrizia; Crowhurst, Simon J; Booth, Linda; Daunt, C (2010): A record of bottom water temperature and seawater d18O for the Southern Ocean over the past 440kyr based on Mg/Ca of benthic foraminiferal Uvigerina spp. Quaternary Science Reviews, 29(1-2), 160-169, https://doi.org/10.1016/j.quascirev.2009.07.013
    Details
    Publication Date: 2024-01-09
    Description: The sensitivity to temperature of Mg/Ca ratios in the shallow-infaunal benthic foraminifera Uvigerina spp. has been assessed. Core-top calibrations over ~1-20 °C show a range in sensitivity of 0.065-0.084 mmol/mol/°C but few data are available spanning the temperature range anticipated in deep-sea records over glacial-interglacial cycles. In contrast to epibenthic foraminiferal species, carbonate ion saturation appears not to affect Mg/Ca significantly. A method based on estimating the ratio of the temperature sensitivity of foraminiferal Mg/Ca to that of d18Ocalcite shows that sensitivity for Mg/Ca at the high end of the observed core-top range (~0.1 mmol/mol/°C) is required for consistency with LGM-Holocene differences in each property as constrained by independent proxy data. This is supported by a Mg/Ca record for Uvigerina spp. generated for the Southern Ocean over the past 440,000 years from Ocean Drilling Program Site 1123 (Chatham Rise, New Zealand). The record shows variability that correlates with climate oscillations. The LGM deep ocean temperature derived from the Mg/Ca record is -1.1 ± 0.3 °C. Transformation to temperature allows estimates to be made of changes in bottom water temperature and seawater d18O and comparison made with literature records. Analysis reveals a ~2.5-kyr lead in the record of temperature over calcite d18O and a longer lead over seawater d18O. This is a reflection of larger phase offsets at eccentricity periods; phase offsets at tilt and precession are within error zero.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Interpolated and normalized Mg/Ca ratios for ODP Site 181-1123 (2012)
    PANGAEA
    Details
    Publication Date: 2024-01-09
    Keywords: 181-1123; AGE; COMPCORE; Composite Core; interpolated; Joides Resolution; Leg181; Magnesium/Calcium ratio; Magnesium/Calcium ratio, maximum; Magnesium/Calcium ratio, minimum; Normalized; Ocean Drilling Program; ODP; South Pacific Ocean
    Type: Dataset
    Format: text/tab-separated-values, 6058 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 3
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    Stable oxygen isotope record and Mg/Ca ratios at the Mid-Pleistocene Climate Transition, ODP Site 181-1123 (2012)
    PANGAEA
    In:  Supplement to: Elderfield, Henry; Ferretti, Patrizia; Greaves, Mervyn; Crowhurst, Simon J; McCave, I Nick; Hodell, David A; Piotrowski, Alexander M (2012): Evolution of ocean temperature and ice volume through the Mid-Pleistocene Climate Transition. Science, 337(6095), 704-709, https://doi.org/10.1126/science.1221294
    Details
    Publication Date: 2024-01-09
    Description: Earth's climate underwent a fundamental change between 1250 and 700 thousand years ago, the Mid-Pleistocene Transition (MPT), when the dominant periodicity of climate cycles changed from 41,000 to 100,000 years in the absence of significant change in orbital forcing. Over this time, an increase occurred in the amplitude of change of deep ocean foraminiferal oxygen isotopic ratios, traditionally interpreted as defining the main rhythm of ice ages although containing large effects of changes in deep-ocean temperature. We have separated the effects of decreasing temperature and increasing global ice volume on oxygen isotope ratios. Our results suggest that the MPT was initiated by an abrupt increase in Antarctic ice volume at 900 ka. We see no evidence of a pattern of gradual cooling but near-freezing temperatures occur at every glacial maximum.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 7 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 4
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    Foraminiferal trace element ratios from South Atlantic sediments (2012)
    PANGAEA
    In:  Supplement to: Boiteau, Rene; Greaves, Mervyn; Elderfield, Henry (2012): Authigenic uranium in foraminiferal coatings: A proxy for ocean redox chemistry. Paleoceanography, 27(3), PA3227, https://doi.org/10.1029/2012PA002335
    Details
    Publication Date: 2024-01-09
    Description: The rate of uranium accumulation in oceanic sediments from seawater is controlled by bottom water oxygen concentrations and organic carbon fluxes-two parameters that are linked to deep ocean storage of CO2. To investigate glacial-interglacial changes in what is known as authigenic U, we have developed a rapid method for its determination as a simple addition to a procedure for foraminiferal trace element analysis. Foraminiferal calcite acts as a low U substrate (U/Ca 〈 15 nmol/mol) upon which authigenic U accumulates in reducing sediments. We measured a downcore record of foraminiferal U/Ca from ODP Site 1090 in the South Atlantic and found that U/Ca ratios increase by 70-320 nmol/mol during glacial intervals. There is a significant correlation between U/Ca records of benthic and planktonic foraminiferal species and between U/Ca and bulk sediment authigenic U. These results indicate that elevated U/Ca ratios are attributable to the accumulation of authigenic U coatings in sediments. Foraminiferal Mn/Ca ratios were lower during the glacial intervals, suggesting that the observed U accumulation on the shells is not directly linked to U incorporation into secondary manganese phases. Thus, foraminiferal U/Ca ratios may provide useful information on past changes in sediment redox conditions.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
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