Preprints
https://doi.org/10.5194/tc-2023-13
https://doi.org/10.5194/tc-2023-13
10 Feb 2023
 | 10 Feb 2023
Status: a revised version of this preprint is currently under review for the journal TC.

Englacial Architecture of Lambert Glacier, East Antarctica

Rebecca J. Sanderson, Kate Winter, S. Louise Callard, Felipe Napoleoni, Neil Ross, Tom A. Jordan, and Robert G. Bingham

Abstract. The analysis of englacial layers using radio-echo sounding data enables the characterisation and reconstruction of current and past ice-sheet flow. Despite the Lambert Glacier catchment being one of the largest in Antarctica, discharging ~16 % of East Antarctica’s ice, its englacial architecture has been little analysed. Here, we present a comprehensive analysis of Lambert Glacier’s englacial architecture using radio-echo sounding data collected by the Antarctica's Gamburtsev Province Project (AGAP) North survey. We used an “internal-layering continuity index” (ILCI) to characterise the internal architecture of the ice and identify four macro-scale ILCI zones with distinct glaciological contexts. Whilst the catchment is dominated by continuous englacial layering, disrupted or discontinuous layering is highlighted by the ILCI at both the onset of enhanced ice flow (defined here as >15 ma−1) and along the shear margin, revealing the transition from internal-deformation-controlled to basal-sliding-dominated ice flow. These zones are characterised by buckled and folded englacial layers which align with the current ice-flow regime, and which we interpret as evidence that the flow direction of the Lambert Glacier trunk has changed little, if at all, during the Holocene. However, disturbed englacial layers along a deep subglacial channel that does not correspond to modern ice-flow routing suggest that ice-flow change has occurred in a former tributary which fed Lambert Glacier from grid north. As large outlet systems such as Lambert Glacier are likely to play a vital role in the future drainage of the East Antarctic Ice Sheet, constraining their englacial architecture to reconstruct their past ice flow and assess basal conditions is important.

Rebecca J. Sanderson et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2023-13', Steven Franke, 10 Mar 2023
    • AC1: 'Reply on RC1', Rebecca Sanderson, 26 May 2023
  • RC2: 'Comment on tc-2023-13', Marie G. P. Cavitte, 27 Mar 2023
    • AC2: 'Reply on RC2', Rebecca Sanderson, 26 May 2023

Rebecca J. Sanderson et al.

Rebecca J. Sanderson et al.

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Short summary
Ice penetrating radar allows us to explore the internal structure of glaciers and ice sheets, to constrain past and present ice flow conditions. In this paper, we examine englacial layers within the Lambert Glacier in East Antarctica using a quantitative layer tracing tool. Analysis reveals that the ice flow here has been relatively stable, but evidence for former fast flow along a tributary suggest that changes have occurred in the past and could change again in the future.