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  • Baseline Surface Radiation Network; BSRN; DATE/TIME; Dronning Maud Land, Antarctica; Georg von Neumayer; GVN; Monitoring station; MONS; Neumayer_based; NEUMAYER III; Ozone total; Radiosonde, Vaisala, DigiCora
  • Ocean Drilling Program; ODP
  • PANGAEA  (2)
  • Nature Publishing Group
  • 2020-2024  (2)
Collection
Keywords
Publisher
  • PANGAEA  (2)
  • Nature Publishing Group
Years
Year
  • 1
    Publication Date: 2024-01-09
    Description: Paired benthic foraminiferal trace metal and stable isotope records have been constructed from equatorial Pacific Ocean Drilling Program Site 1218. The records include the two largest abrupt (〈1 Myr) increases in the Cenozoic benthic oxygen isotope record: Oi‐1 in the earliest Oligocene (∼34 Ma) and Mi‐1 in the earliest Miocene (∼23 Ma). The paired Mg/Ca and oxygen isotope records are used to calculate seawater δ18O (δw). Calculated δw suggests that a large Antarctic ice sheet formed during Oi‐1 and subsequently fluctuated throughout the Oligocene on both short (〈0.5 Myr) and long (2–3 Myr) timescales, between about 50 and 100% of its maximum earliest Oligocene size. The magnitudes of these fluctuations are consistent with estimates of sea level derived from sequence stratigraphy. The transient expansion of the Antarctic ice sheet at Mi‐1 is marked in the benthic δ18O record by two positive excursions between 23.7 and 22.9 Ma, each with a duration of 200–300 kyr. Bottom water temperatures decreased by ∼2°C over the 150 kyr immediately prior to both rapid δ18O excursions. However, the onset of each of these phases of ice growth is synchronous, within the resolution of the records, with the onset of a 2°C warming over ∼150 kyr. We suggest that the warming during these glacial expansions reflect increased greenhouse forcing prompted by a sudden decrease in global chemical weathering rates as Antarctic basement silicate rocks became blanketed by an ice sheet. This represents a negative feedback process that might have operated during major abrupt growth phases of the Antarctic ice sheet.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Expected Availability
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  • 2
    Publication Date: 2024-01-09
    Description: The Latest Danian Event (LDE; ~62.15 Ma) is a major double-spiked eccentricity-driven transient warming event and carbon cycle perturbation (hyperthermal) in the early Paleocene, which has received significantly less attention compared to the larger events of the late Paleocene–early Eocene. A better understanding of the nature of the LDE may broaden our understanding of hyperthermals more generally and improve our knowledge of Earth system responses to extreme climate states. Here we present planktic and benthic foraminiferal Mg/Ca and B/Ca records that shed new light on changes in South Atlantic temperature and carbonate chemistry during the LDE. Our planktic Mg/Ca record reveals a pulsed increase in sea surface temperature of at least ~1.5°C during the older carbon isotope excursion, and ~0.5°C during the younger isotope excursion. We observe drops in planktic and benthic B/Ca, synchronous with pronounced negative excursions in benthic δ13C, which suggest a shift in the carbonate system towards more acidic, dissolved inorganic carbon-rich conditions, in both the surface and deep ocean. Conditions remain more acidic following the LDE, which we suggest may be linked to an enhanced ocean alkalinity sink due to changes in the make-up of planktic calcifiers, hinting at a novel feedback between calcifier ecology and ocean-atmosphere CO2.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Expected Availability
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