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  1. Book ; Online: Stable oxygen isotope record of planktonic foraminifera from late Quaternary sediments of the equatorial Pacific, supplementary data to: Le, Jianning; Shackleton, Nicholas J (1992): Carbonate dissolution fluctuations in the western equatorial Pacific during the Late Quaternary. Paleoceanography, 7(1), 21-42

    Le, Jianning / Shackleton, Nicholas J

    1992  

    Abstract: Planktonic foraminiferal test fragmentation in three cores along a depth transect from the western equatorial Pacific (ERDC-93P, 1619 m; RC17-177, 2600 m; V28-238, 3120 m [Thompson, 1976]) were examined for the last 500 kyr at sample intervals from 2.5 ... ...

    Abstract Planktonic foraminiferal test fragmentation in three cores along a depth transect from the western equatorial Pacific (ERDC-93P, 1619 m; RC17-177, 2600 m; V28-238, 3120 m [Thompson, 1976]) were examined for the last 500 kyr at sample intervals from 2.5 to 5 kyr to study the fluctuations of dissolution in the western equatorial Pacific. The age models were constructed by correlating the delta18O records with the SPECMAP stack [Imbrie et al., 1984]. Results showed that intermediate and deep waters experienced the same patterns of dissolution through climatic cycles. Fragmentation varied with a greater amplitude, and the carbonate ion concentration changed less, in the deep than in the intermediate water. Dissolution has significant variance distributions and coherencies with delta18O over the 100, 41, and 23 kyr periods of orbital variations; dissolution maxima lag ice volume minima by 6 to 20 kyr. The dissolution variability was consistent with recent geochemical models which seek to explain the reduction of atmospheric CO2 concentration at the last glacial maximum [Broecker, 1982; Boyle, 1988].
    Language English
    Dates of publication 1992-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1029/91PA02854
    DOI 10.1594/PANGAEA.727740
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  2. Book ; Conference proceedings ; Online: Benthic foraminiferal stable isotope stratigraphy of ODP Site 138-846 in the tropical Pacific Ocean, supplementary data to: Mix, Alan C; Le, Jianning; Shackleton, Nicholas J (1995): Benthic foraminiferal stable isotope stratigraphy of site 846: 0-1.8 Ma. In: Pisias, NG; Mayer, LA; Janecek, TR; Palmer-Julson, A & van Andel, T H (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station TX (Ocean Drilling program), 138, 839-854

    Mix, Alan C / Le, Jianning / Shackleton, Nicholas J

    1995  

    Abstract: A stable-isotope stratigraphy at Site 846 (tropical Pacific, 3?06'S, 90?49'W, 3307 m water depth), based on the benthic foraminifers Cibicides wuellerstorfi and Uvigerina peregrina, yields a high-resolution record of deep-sea delta18O and delta13C over ... ...

    Abstract A stable-isotope stratigraphy at Site 846 (tropical Pacific, 3?06'S, 90?49'W, 3307 m water depth), based on the benthic foraminifers Cibicides wuellerstorfi and Uvigerina peregrina, yields a high-resolution record of deep-sea delta18O and delta13C over the past 1.8 Ma, with an average sampling interval of 3 k.y. Variance in the delta18O and delta13C records is concentrated in the well-known orbital periods of 100, 41, and 23 k.y. In the 100-k.y. band, both isotopic signals grow from relatively low amplitudes prior to 1.2 Ma, to high amplitudes in the late Quaternary since 0.7 Ma. The amplitude of delta18O and especially of delta13C decreases in the 41-k.y. band as it grows in the 100-k.y. band, consistent with a transfer of energy into an orbitally-paced internal oscillation. A weak 30-k.y. rhythm, present in both delta18O and delta13C, may reflect nonlinear interaction between the 41-k.y. and 100-k.y. bands in the evolving climate system. In the 23-k.y. and 19-k.y. bands associated with orbital precession, delta18O and delta13C are not coherent with each other on long time scales, and do not evolve like the 100-k.y. and 41-k.y. bands. This suggests that the source of the growing 100-k.y. oscillation is not a nonlinear response to precession, in contrast to predictions of some climate models. Sedimentation rates at this site also vary with a strong 100-k.y. cycle. Unlike the isotope records, the amplitude of 100-k.y. variations in sedimentation rate is relatively constant over the past 1.8 Ma, ranging from about 15 to 70 m/m.y. Prior to 0.9 Ma, sedimentation rates co-vary with orbital eccentricity, rather than with global climate as reflected by delta18O or delta13C. A source of this 100-k.y. cycle of sedimentation rate in the absence of similar ice volume fluctuations may be precessional heating of equatorial land masses, which in an energy balance climate model drives variations of monsoonal climates with a 100-k.y. rhythm. For the interval younger than 0.9 Ma, high sedimentation rates in the 100-k.y. band are consistently associated with glacial stages. This change of pattern suggests that when the amplitude of glacial cycles become large enough, their global effects overpower a local monsoon-driven variation in sedimentation rate at Site 846.
    Language English
    Dates of publication 1995-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Conference proceedings ; Online
    Note This dataset is supplement to doi:10.2973/odp.proc.sr.138.160.1995
    DOI 10.1594/PANGAEA.696444
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  3. Book ; Online: Planktic foraminiferal abundance and stable oxygen isotope ratios of sediment cores from the Southern California Borderlands, supplementary data to: Mortyn, P Graham; Thunell, Robert C; Anderson, David M; Stott, Lowell D; Le, Jianning (1996): Sea surface temperature changes in the Southern California Borderlands during the last glacial-interglacial cycle. Paleoceanography, 11(4), 415-430

    Mortyn, P Graham / Anderson, David M / Le, Jianning / Stott, Lowell D / Thunell, Robert C

    1996  

    Abstract: A variety of evidence suggests that average sea surface temperatures (SSTs) during the last glacial maximum in the California Borderlands region were significantly colder than during the Holocene. Planktonic foraminiferal delta18O evidence and average ... ...

    Abstract A variety of evidence suggests that average sea surface temperatures (SSTs) during the last glacial maximum in the California Borderlands region were significantly colder than during the Holocene. Planktonic foraminiferal delta18O evidence and average SST estimates derived by the modern analog technique indicate that temperatures were 6?-10?C cooler during the last glacial relative to the present. The glacial plankton assemblage is dominated by the planktonic foraminifer Neogloboquadrina pachyderma (sinistral coiling) and the coccolith Coccolithus pelagicus, both of which are currently restricted to subpolar regions of the North Pacific. The glacial-interglacial average SST change determined in this study is considerably larger than the 2?C change estimated by Climate: Long-Range Investigation, Mapping, and Prediction (CLIMAP) [1981]. We propose that a strengthened California Current flow was associated with the advance of subpolar surface waters into the Borderlands region during the last glacial.
    Language English
    Dates of publication 1996-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1029/96PA01236
    DOI 10.1594/PANGAEA.729958
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  4. Book ; Online: Stable carbon and oxygen isotope records of Globigerinoides sacculifer from Pacific Ocean sediment cores, supplementary data to: Shackleton, Nicholas J; Le, Jianning; Mix, Alan C; Hall, Michael A (1992): Carbon istotope records from Pacific surface waters and atmospheric carbon dioxide. Quaternary Science Reviews, 11(4), 387-400

    Shackleton, Nicholas J / Hall, Michael A / Le, Jianning / Mix, Alan C

    1992  

    Abstract: We have stacked planktonic carbon isotope data from three cores in the western equatorial Pacific in order to generate a new reconstruction of atmospheric carbon dioxide over the past 450,000 years. Our new reconstruction resembles that of Shackleton et ... ...

    Abstract We have stacked planktonic carbon isotope data from three cores in the western equatorial Pacific in order to generate a new reconstruction of atmospheric carbon dioxide over the past 450,000 years. Our new reconstruction resembles that of Shackleton et al. (1983) based on data from East Pacific core V19-30, which successfully predicted features that were subsequently verified by Barnola et al. (1987) in the record from the Vostock ice core. In addition the new data confirm the discovery of Shackleton and Pisias (1985) that changes in atmospheric CO2 lead changes in ice volume and hence probably contributed to the glacial-interglacial cycles. Our new reconstruction avoids some of the deficiencies of the previous reconstruction: in particular the planktonic species (Neogloboquadrina dutertrei), on which the earlier reconstruction depends, does not calcify in truly nutrient-free surface water as the model assumes, whereas our new reconstruction uses Globigerinoides sacculifer which is expected to be more reliable. In addition, the surface waters in the west Pacific are closer to the nutrient-free ideal on which the model (Broecker, 1982) depends. On the other hand, the amplitude of the new reconstruction is significantly smaller than the amplitude observed by Barnola et al. (1987). It is not clear whether this smaller range is a better estimate of the amplitude of the 'biological pump' effect, or whether the true amplitude is reduced by bioturbation in the west Pacific cores that we studied.
    Language English
    Dates of publication 1992-9999
    Size Online-Ressource
    Publisher PANGAEA - Data Publisher for Earth & Environmental Science
    Publishing place Bremen/Bremerhaven
    Document type Book ; Online
    Note This dataset is supplement to doi:10.1016/0277-3791(92)90021-Y
    DOI 10.1594/PANGAEA.738440
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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