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Abstract Future projections and past reconstructions of Antarctic Ice Sheet stability and sea‐level rise depend on knowledge of continental shelf bathymetry, which controls water circulation under floating ice and interactions between the ice shelf and seafloor. We present a bathymetry model of the Venable Ice Shelf (VIS) in the Bellingshausen Sea sector from an inversion of airborne gravity data. The new model reveals troughs up to ∼1.6 km deeper than previously mapped, providing pathways for warm Circumpolar Deep Water to access the grounding line. A bathymetric high beneath the western VIS is identified as a former pinning point. From crevasse patterns in Landsat satellite imagery, we infer intermittent grounding of the ice shelf on this high since ∼1935, and we interpret these patterns as evidence of mid‐20th century ice‐shelf thinning, in addition to a regrounding between 1970 and 1988, extending the ice‐shelf thickness record beyond the satellite era.
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Boundary condition of grounding lines prior to collapse, Larsen-B Ice Shelf, Antarctica
Top-down rather than bottom-up change The Larsen-B Ice Shelf in Antarctica collapsed in 2002 because of a regional increase in surface temperature. This finding, reported by Rebescoet al., will surprise many who supposed that the shelf's disintegration probably occurred because of thinning of the ice shelf and the resulting loss of support by the sea floor beneath it. The authors mapped the sea floor beneath the ice shelf before it fell apart, which revealed that the modern ice sheet grounding line was established around 12,000 years ago and has since remained unchanged. If the ice shelf did not collapse because of thinning from below, then it must have been caused by warming from above. Science, this issue p.1354
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- PAR ID:
- 10530251
- Publisher / Repository:
- American Association for the Advancement of Science
- Date Published:
- Journal Name:
- Science
- Volume:
- 345
- Issue:
- 6202
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 1354 to 1358
- Subject(s) / Keyword(s):
- Antarctica Antarctic Peninsula Larsen-B Ice Shelf Ice Shelves
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.1256697
