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  • Ocean Drilling Program; ODP  (3)
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  • 1
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    Sea surface temperature reconstruction for the Pliocene-Pleistocene climate transition (2010)
    PANGAEA
    In:  Supplement to: Etourneau, Johan; Schneider, Ralph R; Blanz, Thomas; Martinez, Philippe (2010): Intensification of the Walker and Hadley atmospheric circulations during the Pliocene-Pleistocene climate transition. Earth and Planetary Science Letters, 297(1-2), 103-110, https://doi.org/10.1016/j.epsl.2010.06.010
    Details
    Publication Date: 2024-01-09
    Description: When comparing new sea surface temperature (SST) records between the western and eastern equatorial Pacific spanning the last 3.2 Ma, we found that the zonal temperature gradient over the entire tropical Pacific irreversibly increased by 3 to 4 °C from 2.2 to 2.0 Ma. Here, we suggest a pronounced increase in atmospheric circulation from a weak to a strong zonal Walker circulation (WC) during the early Pleistocene. Evidence from other oceanic areas also suggests a strengthening in the meridional Hadley circulation (HC) during the same time period. Therefore, we also suggest that the invigoration of both atmospheric circulation patterns was intimately coupled during the Plio-Pleistocene transition, and likely linked to a shrinkage in the zonal extension of the tropical to subtropical warm-sphere associated with a prominent increase in the pole to equator temperature gradient. Our conclusion refutes assumptions that the intensification of atmospheric circulation in the tropics and subtropics significantly contributed to the initiation of continental ice sheet formation at high latitudes, since the onset of extensive Northern Hemisphere Glaciation (NHG) occurred ~2.75 Ma ago, in the late Pliocene. Instead, the development of a stronger atmospheric circulation ~2.2-2.0 Ma ago could have significantly contributed to the Plio-Pleistocene climate cooling.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Palynological records from the Congo fan analyzed on ODP Site 175-1077 (2001)
    PANGAEA
    In:  Supplement to: Dupont, Lydie M; Donner, Barbara; Schneider, Ralph R; Wefer, Gerold (2001): Mid-Pleistocene environmental change in tropical Africa began as early as 1.05 Ma. Geology, 29(3), 195-198, https://doi.org/10.1130/0091-7613(2001)029%3C0195:MPECIT%3E2.0.CO;2
    Details
    Publication Date: 2024-01-09
    Description: Palynological records from the Congo fan reveal environmental change in equatorial Africa occurring 1.05 Ma ago, 100 k.y. before the mid-Pleistocene climatic shift at 0.9 Ma. Prior to 1.05 Ma, a glacial-interglacial rhythm is not obvious in the African vegetation variation. Afterwards, Podocarpus spread in the mountains of central Africa mainly during glacials and Congo River discharge decreased. The sequence of vegetation variation associated with the mid-Pleistocene glacials and interglacials differed from that observed during the late Pleistocene. Between 0.9 and 0.6 Ma, interglacials were characterized by warm dry conditions and glacials were characterized by cool humid conditions, while during the past 0.2 Ma glacials were cold and dry and interglacials warm and humid. Our data indicate that before the Northern Hemisphere ice caps dramatically increased in size (0.9?0.6 Ma), low-latitude climate forcing and response in the tropics played an important role in the initiation of 100 k.y. ice-age cycles. During the mid to late Pleistocene, however, the climate conditions in the tropics were increasingly influenced by the glacial-interglacial variations of continental ice sheets.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 7 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 3
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    TOC, TN, d15N isotopes and alkenone concentration in equatorial Pacific sediments (2013)
    PANGAEA
    In:  Supplement to: Etourneau, Johan; Robinson, Rebecca S; Martinez, Philippe; Schneider, Ralph R (2013): Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling. Biogeosciences, 10(8), 5663-5670, https://doi.org/10.5194/bg-10-5663-2013
    Details
    Publication Date: 2024-01-09
    Description: The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene-Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (d15N) and alkenone-derived sea surface temperature (SST) values. This ~0.6 million year long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 4 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
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