Obliquity-paced Pliocene West Antarctic ice sheet oscillations

By T. Naish, R. Powell, R. Levy, G. Wilson, R. Scherer, F. Talarico, L. Krissek, F. Niessen, M. Pompilio, T. Wilson and 46 more. Nature, 2009

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Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth’s orbital geometry control the ice ages, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles. Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the ‘warmer-than-present’ early-Pliocene epoch (∼5–3 Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming. Here we present a marine glacial record from the upper 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, ∼40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth’s axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to ∼3 °C warmer than today and atmospheric CO2 concentration was as high as ∼400 p.p.m.v. (refs 5, 6). The evidence is consistent with a new ice-sheet/ice-shelf model that simulates fluctuations in Antarctic ice volume of up to +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting paced by obliquity. During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt under conditions of elevated CO2.

Subfields: Atmospheric Science, Ecology

View Paper: https://www.semanticscholar.org/paper/c13c30fa02a5357f464e51e7fd096cef891e77b3

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Citations in the corpus

Antarctic topography at the Eocene–Oligocene boundary (2012, neutral): “1. periodically (Naish et al., 2009).”
Origins of species richness in the Indo‐Malay‐Philippine biodiversity hotspot: evidence for the centre of overlap hypothesis (2013, background): “According to fossil and phylogenetic data, most extant reef fauna have a Pliocene (1.6–5.3 Ma) or Miocene (5.3– 23.7 Ma) origin (Renema et al., 2008).”
Genetic evaluation of marine biogeographical barriers: perspectives from two widespread Indo‐Pacific snappers (Lutjanus kasmira and Lutjanus fulvus) (2009, background): “Strong upwelling in the region probably enhanced the effectiveness of the IPB by reducing the availability of suitable habitat for tropical marine organisms (Galloway & Kemp, 1981; Fleminger, 1986; Voris, 2000; Naish et al., 2009).”
Contribution of Antarctica to past and future sea-level rise (2016, neutral): “…with the reduction of thin-ice calving with a similar dependence on α described above, allows ice to expand into interior basins during cool-cli-mate recovery after major retreats of marine-based ice, as presumably occurred many times in West Antarctica over the last several million years 66 .”
A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond (2014, background): “Tectonics and surface processes control the formation of mountain peaks where ice sheets first grow (DeConto & Pollard 2003), the basins where their products are deposited (Naish et al. 2009) and the extent of continental terrain available to host ice sheets (Wilson et al. 2012).”
Sea-level rise due to polar ice-sheet mass loss during past warm periods (2015, background): “In the SouthernHemisphere, theWest Antarctic Ice Sheet (WAIS) experiencedmultiple retreat and advance phases during the Pliocene (19).”
Antarctic silverfish: life strategies of a key species in the high-Antarctic ecosystem (2012, background): “The Ross Sea population of Antarctic silverfish, for example, has experienced periodic collapse of West Antarctic ice sheet with repeated cycles of open marine conditions and warmer water in the Ross embayment as recently as 3–5 Ma (Naish et al. 2009).”
Sea-level and deep-sea-temperature variability over the past 5.3 million years (2014, methodology): “5–6%; and (2) the Mediterranean hydrological cycle is more complicated than in the Red Sea, with major rivers that integrate information from a large catchment area with influences from both temperate climate conditions and the African monsoon.”