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Age‐depth stratigraphy of Pine Island Glacier inferred from airborne radar and ice‐core chronology

Bodart, J.A. ORCID: https://orcid.org/0000-0002-8237-0675; Bingham, R.G.; Ashmore, D.W.; Karlsson, N.B.; Hein, A.S.; Vaughan, D.G. ORCID: https://orcid.org/0000-0002-9065-0570. 2021 Age‐depth stratigraphy of Pine Island Glacier inferred from airborne radar and ice‐core chronology. Journal of Geophysical Research: Earth Surface, 126 (4), e2020JF005927. 20, pp. https://doi.org/10.1029/2020JF005927

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Abstract/Summary

Understanding the contribution of the West Antarctic Ice Sheet (WAIS) to past and future sea level has been a major scientific priority over the last three decades. In recent years, observed thinning and ice‐flow acceleration of the marine‐based Pine Island Glacier has highlighted that understanding dynamic changes is critical to predicting the long‐term stability of the WAIS. However, relatively little is known about the evolution of the catchment during the Holocene. Internal Reflecting Horizons (IRHs) provide a cumulative record of accumulation, basal melt and ice dynamics that, if dated, can be used to constrain ice‐flow models. Here, we use airborne radars to trace four spatially‐extensive IRHs deposited in the late Quaternary across the Pine Island Glacier catchment. We use the WAIS Divide ice‐core chronology to assign ages to three IRHs: 4.72 ± 0.28, 6.94 ± 0.31, and 16.50 ± 0.79 ka. We use a 1‐D model, constrained by observational and modelled accumulation rates, to produce an independent validation of our ice‐core‐derived ages and provide an age estimate for our shallowest IRH (2.31‐2.92 ka). We find that our upper three IRHs correspond to three large peaks in sulphate concentrations in the WAIS Divide ice‐core record and hypothesise that the origin of these spatially‐extensive IRHs is from past volcanic activity. The clear correspondence between our IRHs and the ones previously identified over the Weddell Sea Sector, altogether representing ∼20% of the WAIS, indicates that a unique set of stratigraphic markers spanning the Holocene exists over a large part of West Antarctica.

Item Type: Publication - Article
Digital Object Identifier (DOI): https://doi.org/10.1029/2020JF005927
ISSN: 2169-9003
Additional Keywords: Pine Island Glacier, Holocene, Ice Penetrating Radar, West Antarctica, Englacial Stratigraphy, Thwaites Glacier
Date made live: 25 Mar 2021 16:18 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/529956

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