Subglacial Geology and Geomorphology of the Pensacola‐Pole Basin, East Antarctica

Abstract

The East Antarctic Ice Sheet (EAIS) is underlain by a series of low‐lying subglacial sedimentary basins. The extent, geology, and basal topography of these sedimentary basins are important boundary conditions governing the dynamics of the overlying ice sheet. This is particularly pertinent for basins close to the grounding line wherein the EAIS is grounded below sea level and therefore potentially vulnerable to rapid retreat. Here we analyze newly acquired airborne geophysical data over the Pensacola‐Pole Basin (PPB), a previously unexplored sector of the EAIS. Using a combination of gravity and magnetic and ice‐penetrating radar data, we present the first detailed subglacial sedimentary basin model for the PPB. Radar data reveal that the PPB is defined by a topographic depression situated ~500 m below sea level. Gravity and magnetic depth‐to‐source modeling indicate that the southern part of the basin is underlain by a sedimentary succession 2–3 km thick. This is interpreted as an equivalent of the Beacon Supergroup and associated Ferrar dolerites that are exposed along the margin of East Antarctica. However, we find that similar rocks appear to be largely absent from the northern part of the basin, close to the present‐day grounding line. In addition, the eastern margin of the basin is characterized by a major geological boundary and a system of overdeepened subglacial troughs. We suggest that these characteristics of the basin may reflect the behavior of past ice sheets and/or exert an influence on the present‐day dynamics of the overlying EAIS.

Five decades of radioglaciology

“…However, several regions remained free of data (Pritchard, 2014). Other compilations are now due that will incorporate new data that have been acquired to fill many of Bedmap2's gaps, including, for example, across Marie Byrd Land, West Antarctica, the Recovery Basin/South Pole, the Dome F region and Princess Elisabeth Land, as well as newly remastered TUD-NSF-SPRI film data and updated thickness measurements for the Ross Ice Shelf (Tang and others, 2016; Young and others, 2016; Popov, 2017; Humbert and others, 2018; Jordan and others, 2018a; Karlsson and others, 2018; Morlighem and others, 2019; Paxman and others, 2019; Schroeder and others, 2019; Tinto and others, 2019). Compared to Antarctica, surveys of Greenland starting in the 1990s by the University of Kansas as part of NASA's Program for Arctic Regional Climate Assessment (PARCA) and later OIB have led to relatively abundant and mutually interpretable observations of the ice-sheet bed and englacial properties (Bamber and others, 2013; Gogineni and others, 2014; MacGregor and others, 2015a; Morlighem and others, 2017).…”

East Antarctica magnetically linked to its ancient neighbours in Gondwana

“…Large-scale international aeromagnetic www.nature.com/scientificreports/ exploration in Antarctica has continued since ADMAP-2, with major more recent surveys flown e.g. over the Recovery and South Pole frontiers 48,49 . For Southern Africa (Fig.…”

The Antarctic Crust and Upper Mantle: A Flexible 3D Model and Software Framework for Interdisciplinary Research

“…Modeling studies that are particularly important in the Antarctic context include making use of the curvature of gravity field (Ebbing et al, 2018), finding the elastic crustal thickness (Chen et al, 2018), comparison of models of, e.g., Moho depth from various approaches (Baranov et al, 2018;Pappa et al, 2019) and integrating density, compositional and thermal models (Haeger et al, 2019). Interpretation of magnetic anomalies combined with other datasets can support delineation of crustal domains (Goodge and Finn, 2010;Aitken et al, 2014;Ruppel et al, 2018;Paxman et al, 2019), and are also used to infer depth to the Curie temperature isotherm (Maule et al, 2005;Martos et al, 2017).…”

“…Understanding of the subglacial landscape evolution by erosion and deposition calls for an interdisciplinary approach, whereby ice sheet development, geophysical data and geological data are combined to constrain Antarctica's past and present landscape, and isostasy (Jamieson and Sugden, 2008;Jamieson et al, 2010;Mackintosh et al, 2014;Paxman et al, 2016;Paxman et al, 2018;Paxman et al, 2019).…”