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  • 1
    In: The Cryosphere, Copernicus GmbH, Vol. 14, No. 12 ( 2020-12-10), p. 4507-4524
    Abstract: Abstract. Subglacial water plays an important role in ice sheet dynamics and stability. Subglacial lakes are often located at the onset of ice streams and have been hypothesised to enhance ice flow downstream by lubricating the ice–bed interface. The most recent subglacial-lake inventory of Antarctica mapped nearly 400 lakes, of which ∼ 14 % are found in West Antarctica. Despite the potential importance of subglacial water for ice dynamics, there is a lack of detailed subglacial-water characterisation in West Antarctica. Using radio-echo sounding data, we analyse the ice–bed interface to detect subglacial lakes. We report 33 previously uncharted subglacial lakes and present a systematic analysis of their physical properties. This represents a ∼ 40 % increase in subglacial lakes in West Antarctica. Additionally, a new digital elevation model of basal topography of the Ellsworth Subglacial Highlands was built and used to create a hydropotential model to simulate the subglacial hydrological network. This allows us to characterise basal hydrology, determine subglacial water catchments and assess their connectivity. We show that the simulated subglacial hydrological catchments of the Rutford Ice Stream, Pine Island Glacier and Thwaites Glacier do not correspond to their ice surface catchments.
    Type of Medium: Online Resource
    ISSN: 1994-0424
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2020
    detail.hit.zdb_id: 2393169-3
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  • 2
    In: Nature, Springer Science and Business Media LLC, Vol. 608, No. 7922 ( 2022-08-11), p. 275-286
    Type of Medium: Online Resource
    ISSN: 0028-0836 , 1476-4687
    RVK:
    RVK:
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    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 120714-3
    detail.hit.zdb_id: 1413423-8
    SSG: 11
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  • 3
    Online Resource
    Online Resource
    American Geophysical Union (AGU) ; 2020
    In:  Geophysical Research Letters Vol. 47, No. 20 ( 2020-10-28)
    In: Geophysical Research Letters, American Geophysical Union (AGU), Vol. 47, No. 20 ( 2020-10-28)
    Abstract: We investigate the influence of the progressive evolution of bed topography on the sensitivity of the Antarctic Ice Sheet to climatic change Bed topographic evolution since 34 Ma causes a doubling in Antarctic ice volume loss in our schematic ice sheet model experiments Antarctic Ice Sheet sensitivity to climate and ocean forcing has been substantially amplified by long‐term landscape evolution
    Type of Medium: Online Resource
    ISSN: 0094-8276 , 1944-8007
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2020
    detail.hit.zdb_id: 2021599-X
    detail.hit.zdb_id: 7403-2
    SSG: 16,13
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  • 4
    Online Resource
    Online Resource
    American Geophysical Union (AGU) ; 2021
    In:  Journal of Geophysical Research: Earth Surface Vol. 126, No. 12 ( 2021-12)
    In: Journal of Geophysical Research: Earth Surface, American Geophysical Union (AGU), Vol. 126, No. 12 ( 2021-12)
    Abstract: Analysis of airborne radio‐echo sounding data reveals an extensive subglacial valley network in northern Greenland The network developed over multi‐million‐year timescales and is paleo‐fluvial in origin with localized modification by glacial processes The channel profile records two phases of base level fall, which may have been induced by widespread Neogene uplift events in Greenland
    Type of Medium: Online Resource
    ISSN: 2169-9003 , 2169-9011
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2021
    detail.hit.zdb_id: 3094104-0
    detail.hit.zdb_id: 2130824-X
    detail.hit.zdb_id: 2138320-0
    SSG: 16,13
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  • 5
    In: The Cryosphere, Copernicus GmbH, Vol. 18, No. 5 ( 2024-05-07), p. 2277-2296
    Abstract: Abstract. The subglacial landscape of Antarctica records and influences the behaviour of its overlying ice sheet. However, in many places, the evolution of the landscape and its control on ice sheet behaviour have not been investigated in detail. Using recently released radio-echo sounding data, we investigate the subglacial landscape of the Evans–Rutford region of West Antarctica. Following quantitative analysis of the landscape morphology under ice-loaded and ice-unloaded conditions, we identify 10 flat surfaces distributed across the region. Across these 10 surfaces, we identify two distinct populations based on clustering of elevations, which potentially represent remnants of regionally coherent pre-glacial surfaces underlying the West Antarctic Ice Sheet (WAIS). The surfaces are bounded by deeply incised glacial troughs, some of which have potential tectonic controls. We assess two hypotheses for the evolution of the regional landscape: (1) passive-margin evolution associated with the break-up of the Gondwana supercontinent or (2) an extensive planation surface that may have been uplifted in association with either the West Antarctic Rift System or cessation of subduction at the base of the Antarctic Peninsula. We suggest that passive-margin evolution is the most likely of these two mechanisms, with the erosion of glacial troughs adjacent to, and incising, the flat surfaces likely having coincided with the growth of the WAIS. These flat surfaces also demonstrate similarities to other identified surfaces, indicating that a similar formational process may have been acting more widely around the Weddell Sea embayment. The subsequent fluctuations of ice flow, basal thermal regime, and erosion patterns of the WAIS are therefore controlled by the regional tectonic structures.
    Type of Medium: Online Resource
    ISSN: 1994-0424
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2024
    detail.hit.zdb_id: 2393169-3
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  • 6
    Online Resource
    Online Resource
    Geological Society of London ; 2023
    In:  Geological Society, London, Memoirs Vol. 56, No. 1 ( 2023-02-06), p. 231-251
    In: Geological Society, London, Memoirs, Geological Society of London, Vol. 56, No. 1 ( 2023-02-06), p. 231-251
    Abstract: The development of a robust understanding of the response of the Antarctic Ice Sheet to present and projected future climatic change is a matter of key global societal importance. Numerical ice sheet models that simulate future ice sheet behaviour are typically evaluated with recourse to how well they reproduce past ice sheet behaviour, which is constrained by the geological record. However, subglacial topography, a key boundary condition in ice sheet models, has evolved significantly throughout Antarctica's glacial history. Since mantle processes play a fundamental role in the generation and modification of topography over geological timescales, an understanding of the interactions between the Antarctic mantle and palaeotopography is crucial for developing more accurate simulations of past ice sheet dynamics. This chapter provides a review of the influence of the Antarctic mantle on the long-term evolution of the subglacial landscape, through processes including structural inheritance, flexural isostatic adjustment, lithospheric cooling and thermal subsidence, volcanism and dynamic topography. The uncertainties associated with reconstructing these processes through time are discussed, as are important directions for future research and the implications of the evolving subglacial topography for the response of the Antarctic Ice Sheet to climatic and oceanographic change.
    Type of Medium: Online Resource
    ISSN: 0435-4052 , 2041-4722
    Language: English
    Publisher: Geological Society of London
    Publication Date: 2023
    detail.hit.zdb_id: 961207-5
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  • 7
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2022
    In:  Scientific Reports Vol. 12, No. 1 ( 2022-07-06)
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2022-07-06)
    Abstract: The land surface beneath the Greenland and Antarctic Ice Sheets is isostatically suppressed by the mass of the overlying ice. Accurate computation of the land elevation in the absence of ice is important when considering, for example, regional geodynamics, geomorphology, and ice sheet behaviour. Here, we use contemporary compilations of ice thickness and lithospheric effective elastic thickness to calculate the fully re-equilibrated isostatic response of the solid Earth to the complete removal of the Greenland and Antarctic Ice Sheets. We use an elastic plate flexure model to compute the isostatic response to the unloading of the modern ice sheet loads, and a self-gravitating viscoelastic Earth model to make an adjustment for the remaining isostatic disequilibrium driven by ice mass loss since the Last Glacial Maximum. Feedbacks arising from water loading in areas situated below sea level after ice sheet removal are also taken into account. In addition, we quantify the uncertainties in the total isostatic response associated with a range of elastic and viscoelastic Earth properties. We find that the maximum change in bed elevation following full re-equilibration occurs over the centre of the landmasses and is +783 m in Greenland and +936 m in Antarctica. By contrast, areas around the ice margins experience up to 123 m of lowering due to a combination of sea level rise, peripheral bulge collapse, and water loading. The computed isostatic response fields are openly accessible and have a number of applications for studying regional geodynamics, landscape evolution, cryosphere dynamics, and relative sea level change.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2615211-3
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  • 8
    In: AGU Advances, American Geophysical Union (AGU), Vol. 4, No. 2 ( 2023-04)
    Abstract: We use constitutive models including transient deformation to infer the full‐spectrum mechanical behavior of the Greenland upper mantle Contribution of transient deformation is most significant over centennial to millennial timescales relating to historical ice mass change Transient effects may explain conflicting mantle viscosity and lithosphere thickness estimates from geodetic and geological observations
    Type of Medium: Online Resource
    ISSN: 2576-604X , 2576-604X
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2023
    detail.hit.zdb_id: 3008306-0
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