Novel Record of Intermittent Grounding of the Venable Ice Shelf Since 1935 From Operation IceBridge Airborne‐Gravity‐Derived Bathymetry and Landsat Imagery

Abstract

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.

Keywords

• bathymetry
• west Antarctica
• Venable Ice Shelf
• Abbot Ice Shelf
• ice shelves
• gravity