Pliocene-pleistocene seismic stratigraphy of the Ross Sea: Evidence for multiple ice sheet grounding episodes

Alonso, Belén; Anderson, John B.; Díaz, José Ignacio; Bartek, Louis R.

doi:10.1029/ar057p0093

Cited by 63 publications

(58 citation statements)

References 16 publications

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“…fig. 3 of Alonso et al, 1992), but the dimensions of sedimentary units are very different: progradation is more extensive, and the slope less steep (effects, probably, of the different catchments). In Prydz Bay too, a similar mid-section erosional episode is widespread within the prograded wedge (Cooper et al, 1991b;Leitchenkov et al, 1994;Barker, 1995).…”

Section: Regional and Time Variationmentioning

confidence: 99%

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Antarctic glacial history from numerical models and continental margin sediments

Barker

Barrett

Cooper

et al. 1999

Palaeogeography, Palaeoclimatology, Palaeoecology

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The climate record of glacially transported sediments in prograded wedges around the Antarctic outer continental shelf, and their derivatives in continental rise drifts, may be combined to produce an Antarctic ice sheet history, using numerical models of ice sheet response to temperature and sea-level change. Examination of published models suggests several preliminary conclusions about ice sheet history. The ice sheet's present high sensitivity to sea-level change at short (orbital) periods was developed gradually as its size increased, replacing a declining sensitivity to temperature. Models suggest that the ice sheet grew abruptly to 40% (or possibly more) of its present size at the Eocene-Oligocene boundary, mainly as a result of its own temperature sensitivity. A large but more gradual middle Miocene change was externally driven, probably by development of the Antarctic Circumpolar Current (ACC) and Polar Front, provided that a few million years' delay can be explained. The Oligocene ice sheet varied considerably in size and areal extent, but the late Miocene ice sheet was more stable, though significantly warmer than today's. This difference probably relates to the confining effect of the Antarctic continental margin. Present-day numerical models of ice sheet development are sufficient to guide current sampling plans, but sea-ice formation, polar wander, basal topography and ice streaming can be identified as factors meriting additional modelling effort in the future.

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Section: Regional and Time Variationmentioning

confidence: 99%

“…Bentley, 1984;Fastook, 1984), the geometry of the prograding sediment wedge in the eastern Ross Sea (e.g. Alonso et al, 1992) is different from that off the Antarctic Peninsula (Fig. 4), reflecting its different catchment characteristics.…”

Section: Regional and Time Variationmentioning

confidence: 99%

Antarctic glacial history from numerical models and continental margin sediments

Barker

Barrett

Cooper

et al. 1999

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…Pliocene data from Core AND-1B indicate that orbitally induced oscillations of the WAIS resulted in transitions from grounded ice and/or ice shelves to open-water conditions McKay et al, 2012). However, previous seismic stratigraphic work on the Ross Sea shelf beyond Site AND-1B revealed only seven shelf-wide grounding events (Alonso et al, 1992). Given the location of Site AND-1B, which is subject to overriding from both the East Antarctic Ice Sheet (EAIS) and the WAIS, the ANDRILL results are likely not representative of the WAIS outlets in the Amundsen and Weddell Seas.…”

Section: Introductionmentioning

confidence: 87%

Untitled

Gohl¹,

Wellner²,

Klaus³

2017

International Ocean Discovery Program Scientific Prospectus

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The West Antarctic Ice Sheet (WAIS) is largely marine based and thus highly sensitive to both climatic and oceanographic changes. Therefore, the WAIS has likely had a very dynamic history over the last several million years. A complete collapse of the WAIS would result in a global sea level rise of 3.3-4.3 m, yet the world's scientific community is not able to predict its future behavior. Moreover, knowledge about past behavior of the WAIS is poor, in particular during geological times with climatic conditions similar to those expected for the near and distant future. Reconstructions and quantifications of partial or complete WAIS collapses in the past are urgently needed for constraining and testing ice sheet models that aim to predict future WAIS behavior and the potential contribution of the WAIS to global sea level rise. Large uncertainties exist regarding the chronology, extent, rates, and spatial and temporal variability of past advances and retreats of the WAIS across the continental shelves. These uncertainties largely result from the fundamental lack of data from drill cores recovered proximal to the WAIS. The continental shelf and rise of the Amundsen Sea are prime targets for drilling because the records are expected to yield archives of pure WAIS dynamics unaffected by other ice sheets and the WAIS sector draining into the Amundsen Sea Embayment (ASE) currently experiences the largest ice loss in Antarctica (Paolo et al., 2015).We propose a series of drill sites for the ASE shelf where seismic data reveal seaward-dipping sedimentary sequences that span from the preglacial depositional phase to the most recent glacial periods. Our strategy is to drill a transect from the oldest sequences close to the bedrock/basin boundary at the middle-inner shelf transition to the youngest sequences on the outer shelf in the eastern ASE. If the eastern ASE is inaccessible due to sea ice cover, a similar transect of sites can be drilled on the western ASE. The core transect will provide a detailed history of the glacial cycles in the Amundsen Sea region and allow comparison to the glacial history from the Ross Sea sector. In addition, deep-water sites on the continental rise of the Amundsen Sea are selected for recovering continuous records of glacially transported sediments and detailed archives of climatic and oceanographic changes throughout glacial-interglacial cycles. We will apply a broad suite of analytical techniques, including multiproxy analyses, to address our objectives of reconstructing the onset of glaciation in the greenhouse to icehouse transition, processes of dynamic ice sheet behavior during the Neogene and Quaternary, and ocean conditions associated with the glacial cycles.The five principal objectives of Expedition 379 are as follows:1. To reconstruct the glacial history of West Antarctica from the Paleogene to recent times and the dynamic behavior of the WAIS during the Neogene and Quaternary, especially possible partial or full WAIS collapses, and the WAIS contribution to past sea level...

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“…Bartek et al [I9911 attributed the change in the PlioPleistocene section of the Ross Sea from progradation in the lower part of the section to aggradation in the upper part of the section (Figure 2; Cooper et ul. [1991b]; Alonso et al [1992]) to increased frequency of eustatic cycles. They reasoned that, because the longevity of ice grounding events diminished, the delivery of sediments to the outer shelf and slope significantly decreased, and therefore seaward progradation of the shelf greatly diminished.…”

Section: Sea-level Curve and Constant Sediment Transportmentioning

confidence: 99%

“…The equivalent stratal geometries to low-stand and transgressive systems tracts (in low latitude) have not been identified [Cooper et ul., 1991bl. Aggradation of thin, continuous layers and extensive seaward progradation of proglacial glaciomarine sediments characterize the depositional sequences of the Antarctic shelf ( Figure 2a and the upper section of Figure 2b; Anderson [1991]; Alonso et al [1992]). Toplap and offlap relations are observed on the outer shelf (Figure lb), where only a few unconformities truncate steeply dipping prograded sequences ( Figure la).…”

Section: Introductionmentioning

confidence: 99%

Morphology and Stratal Geometry of the Antarctic Continental Shelf: Insights from Models

Brink

Schneider

Johnson

2013

Geology and Seismic Stratigraphy of the Antarctic Margin

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Reconstruction of past ice-sheet fluctuations from the stratigraphy of glaciated continental shelves requires understanding of the relationships among the stratal geometry, glacial and marine sedimentary processes, and ice dynamics. We investigate the formation of the morphology and the broad stratal geometry of topsets on the Antarctic continental shelf with numerical models. Our models assume that the stratal geometry and morphology are principally the results of time-integrated effects of glacial erosion and sedimentation related to the location of the seaward edge of the grounded ice. The location of the grounding line varies with time almost randomly across the shelf. With these simple assumptions, the models can successfully mimic salient features of the morphology and the stratal geometry. The models suggest that the current shelf has gradually evolved to its present geometry by many glacial advances and retreats of the grounding line to different locations across the shelf. The locations of the grounding line do not appear to be linearly correlated with either fluctuations in the 6180 record (which presumably represents changes in the global ice volume) or with the global sea-level curve, suggesting that either a more complex relationship exists or local effects dominate. The models suggest that erosion of preglacial sediments is confined to the inner shelf, and erosion decreases and deposition increases toward the shelf edge. Some of the deposited glacial sediments must be derived from continental erosion. The sediments probably undergo extensive transport and reworking obliterating much of the evidence for their original depositional environment. The flexural rigidity and the tectonic subsidence of the underlying lithosphere modify the bathyrnetry of the shelf, but probably have little effect on the stratal geometry. Our models provide several guidelines for the interpretation of unconformities, the nature of preserved topset deposits, and the significance of progradation versus aggradation of shelf sediments.

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Pliocene-pleistocene seismic stratigraphy of the Ross Sea: Evidence for multiple ice sheet grounding episodes

Cited by 63 publications

References 16 publications

Antarctic glacial history from numerical models and continental margin sediments

Antarctic glacial history from numerical models and continental margin sediments

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Morphology and Stratal Geometry of the Antarctic Continental Shelf: Insights from Models

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