Marine Ice Beneath the Ross Ice Shelf Imaged with Side-Looking GPR: Implications for Stability Within the McMurdo Shear Zone

PreviousNext No Access18th International Conference on Ground Penetrating Radar, Golden, Colorado, 14–19 June 2020Marine ice beneath the Ross Ice Shelf imaged with side-looking GPR: Implications for stability within the McMurdo shear zoneAuthors: Steven ArconeSteven ArconeClimate Change Institute, University of Maine, United StatesSearch for more papers by this authorhttps://doi.org/10.1190/gpr2020-017.1 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract 100 MHz GPR profiles recorded over the McMurdo Shear Zone, within the western Ross Ice Shelf near McMurdo Station, imaged marine ice beneath about 160 m of meteoric firn and englacial ice. Crevassing exists to about 40 m depth in the firn, while no crevassing was found within the 120–130 m of meteoric ice below the firn. However, below the meteoric ice marine ice was imaged to about 15–20 m depth. Multiple parallel transects spaced 50 m and the 160 m depth to the marine ice helped show that the GPR performed as side-looking radar because continuous crevasse strikes were imaged and matched between transects. The stratified marine ice was riddled with linear and curvilinear crevasses at various orientations, and crevasses likely filled with unstratified marine ice, meaning that seawater had penetrated from the bottom. Hydrostatic considerations predict the marine ice may be 30–50 m thick beneath the crevassed section, and possibly thicker beyond it. Although unexpected but fortunate, the lack of crevassing within the meteoric ice is stronger evidence for present shelf stability, while the crevassing in the marine ice signifies instability. Keywords: Antarctica, GPR, marine, offset, reflectionPermalink: https://doi.org/10.1190/gpr2020-017.1FiguresReferencesRelatedDetails 18th International Conference on Ground Penetrating Radar, Golden, Colorado, 14–19 June 2020ISSN (online):2159-6832Copyright: 2020 Pages: 455 publication data© 2020 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 11 Nov 2020 CITATION INFORMATION Steven Arcone, (2020), "Marine ice beneath the Ross Ice Shelf imaged with side-looking GPR: Implications for stability within the McMurdo shear zone," SEG Global Meeting Abstracts : 61-64. https://doi.org/10.1190/gpr2020-017.1 Plain-Language Summary KeywordsAntarcticaGPRmarineoffsetreflectionPDF DownloadLoading ...