Inferring Ice Fabric From Birefringence Loss in Airborne Radargrams: Application to the Eastern Shear Margin of Thwaites Glacier, West Antarctica ...

• Main Authors: Young, TJ, Schroeder, DM, Jordan, TM, Christoffersen, P, Tulaczyk, SM, Culberg, R, Bienert, NL
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2021
• Subjects: Antarctica; birefringence; fabric; glaciology; ice penetrating radar; polarimetry; Thwaites Glacier; West Antarctica; Antarc*
• Online Access: https://dx.doi.org/10.17863/cam.68878; https://www.repository.cam.ac.uk/handle/1810/321755

AbstractIn airborne radargrams, undulating periodic patterns in amplitude that overprint traditional radiostratigraphic layering are occasionally observed, however, they have yet to be analyzed from a geophysical or glaciological perspective. We present evidence supported by theory that these depth‐periodic patterns are consistent with a modulation of the received radar power due to the birefringence of polar ice, and therefore indicate the presence of bulk fabric anisotropy. Here, we investigate the periodic component of birefringence‐induced radar power recorded in airborne radar data at the eastern shear margin of Thwaites Glacier and quantify the lateral variation in azimuthal fabric strength across this margin. We find the depth variability of birefringence periodicity crossing the shear margin to be a visual expression of its shear state and its development, which appears consistent with present‐day ice deformation. The morphology of the birefringent patterns is centered at the location of maximum ...