From the Antarctic Continental Shelf to Plate Boundaries: Applications of Airborne Gravity Data from Transit Flights

Understanding the Solid Earth structure beneath ice shelves and glaciers is essential for predicting their interaction with ocean circulation and the evolution of Polar Regions. This study focuses on the innovative use of airborne gravimetric data collected during transit flights to improve bathymetric and tectonic models in Antarctica and the surrounding regions.

We first present a detailed bathymetric model of the Cook Ice Shelf, Ninnis Glacier Tongue, and the surrounding continental shelf edge derived from airborne gravity inversion. This model improves our understanding of water pathways connecting the continental shelf to the ice shelves, a critical factor for analyzing basal melt processes. Localized basins (~1400 m deep) beneath the ice shelves and shallow areas (~200 m) near Cape Freshfield were identified, with seafloor depths near grounding lines exceeding the observed depths of modified Circumpolar Deep Water (< 350 m). For the first time, transit flight gravity anomalies were used to propose a new position for the continental shelf edge (~27 km north of its currently mapped location), challenging previous assumptions about the extent of the Cook Shelf Depression.

Building on this work, we explore further applications of transit flight gravity data in tectonic studies of the region between South America and Antarctica, encompassing the South American, Scotia, Shetland and Antarctic plates. These datasets, compared with satellite-derived gravity models and ship-based data, are evaluated for their potential to refine bathymetric grids and address gaps in tectonic understanding. Preliminary results suggest that airborne gravimetry, with appropriate filtering and leveling, can provide valuable insights into regions where traditional methods face limitations, such as beneath ice shelves or in sparsely surveyed areas.

Our ongoing efforts focus on optimizing data processing to enhance resolution and combining these results with existing tectonic models. By addressing questions such as the resolution achievable for gravity-based bathymetric inversions and the integration of sparse data into robust models, this research seeks to expand the applicability of transit flight data. These insights will contribute to understanding the lithospheric structure and plate interactions in the Southern Ocean, bridging gaps in knowledge critical for both solid-earth and cryospheric studies.

This work exemplifies the importance of integrating novel data sources, such as transit flight gravimetric data, into comprehensive models that connect the solid Earth and ice dynamics. By doing so, we aim to improve the understanding of tectonic and subglacial processes that influence the evolution of Polar Regions.