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  • This is GNSS data of four stations covering the grounding zone of Priestley Glacier Antarctica. Tidal modulation of ice streams and their adjacent ice shelves is a real-world experiment to understand ice-dynamic processes. We observe the dynamics of Priestley Glacier, Antarctica, using Terrestrial Radar Interferometry (TRI) and GNSS. Ocean tides are predominantly diurnal but horizontal GNSS displacements oscillate also semi-diurnally. The oscillations are strongest in the ice shelf and tidal signatures decay near-linearly in the TRI data over >10 km upstream of the grounding line. Tidal flexing is observed >6 km upstream of the grounding line including cm-scale uplift. Tidal grounding line migration is small and <40 % of the ice thickness. The frequency doubling of horizontal displacements relative to the ocean tides is consistent with variable ice-shelf buttressing demonstrated with a visco-elastic Maxwell model. Taken together, this supports previously hypothesized flexural ice softening in the grounding-zone through tides and offers new observational constraints for the role of ice rheology in ice-shelf buttressing. Related Publication: Drews, R., Wild, C. T., Marsh, O. J., Rack, W., Ehlers, T. A., Neckel, N., & Helm, V. (2021). Grounding-zone flow variability of Priestley Glacier, Antarctica, in a diurnal tidal regime. Geophysical Research Letters, 48, e2021GL093853. https://doi.org/10.1029/2021GL093853 GET DATA: https://doi.pangaea.de/10.1594/PANGAEA.936090

  • This metadata record represents the first direct comparison of seismic and ultrasonic data with measured crystallographic preferred orientations Crystallographic preferred orientations (CPO) in a polar shear margin (Priestly Glacier, Antarctica). Analyses of seismic, ultrasonic and measured CPO datasets were combined to assess the potential of active-source seismic surveys for the constraint of shear margin anisotropy, which provide an assessment of ice flow dynamics and stability. A continuous ice core of 58 m length was drilled and recovered in December 2019 and January 2020 in a lateral shear margin of the Priestley Glacier, located in Victoria Land, Antarctica. Core samples were analysed for CPO using electron backscatter diffraction (EBSD) measurements. The core orientation was carefully preserved during drilling, which enabled azimuthal orientation of the CPO. To complete the link between seismic anisotropy of the ice volume around the borehole and CPO measurements from the core, multi-azimuthal ultrasonic velocity measurements were made on core samples in the laboratory. The vertical-seismic-profile (VSP) dataset was recorded at the Priestley drill site using a three-component borehole seismometer to investigate seismic properties and anisotropy within the glacier ice. Additionally, multi-azimuthal ultrasonic velocity measurements were conducted on core samples in the laboratory, complementing the seismic data analysis. Further details are provided at: Lutz, F., Prior, D.J., Still, H., Hamish Bowman, M., Boucinhas, B., Craw, L., Fan, S., Kim, D., Mulvaney, R., Thomas, R.E., & Hulbe, C.L. (2022). Ultrasonic and seismic constraints on crystallographic preferred orientations of the Priestley Glacier shear margin, Antarctica. *Cryosphere*, 16(8), 3313-3329. https://doi.org/10.5194/tc-16-3313-2022 GET DATA: https://auckland.figshare.com/articles/dataset/Priestley_Glacier_seismic_and_ultrasonic_constraints_on_crystallographic_orientation/17108639

  • This metadata record presents observations of ice shelf anisotropy derived from borehole seismic data. Hot-water-drilled boreholes were created at two sites: Windless Bight (WB) near the grounding line on Ross Island and HWD-2 in the central Ross Ice Shelf. The boreholes housed seismometers frozen at various depths within the ice, enabling seismic observations of shear wave splitting (SWS) using active seismic sources. At Windless Blight, borehole seismometers were installed at depths of 40 and 190 meters within the ∼220 m thick ice shelf during the 2016/2017 Antarctic field season. Seismic shots were recorded with a 2,000 Hz sampling rate and a 2 s record length, triggered by striking plates. The site was revisited in December 2017 to validate sensor survivability and reproduce survey geometry for SWS analysis using multiazimuth shots. At HWD-2, eight seismometers were deployed at depths ranging from 80 to 325 meters inside the ∼370 m thick ice shelf during the 2017/2018 field season. A total of 747 shots at 53 different shot points were recorded, with clear observations of split shear waves in the data. The study contributes valuable seismic data and methodology for understanding ice shelf anisotropy, enhancing our knowledge of Antarctic ice dynamics and seismic behavior. Further details are provided at: Lutz, F., Eccles, J., Prior, D. J., Craw, L.,Fan, S., Hulbe, C., et al. (2020). Constraining ice shelf anisotropy using shear wave splitting measurements from active‐source borehole seismics.Journal of Geophysical Research: EarthSurface,125, e2020JF005707. https://doi.org/10.1029/2020JF005707 GET DATA: https://auckland.figshare.com/s/9f783802272b825d7ad7

  • These data were aquired with a Terrestrial Radar Interferometer overlooking the grounding zone of Priestley Glacier, Antarctica. The time series contains differential interferograms with a 12h temporal baseline covering an approximately 8 day period in November 2018. Tidal modulation of ice streams and their adjacent ice shelves is a real-world experiment to understand ice-dynamic processes. We observe the dynamics of Priestley Glacier, Antarctica, using Terrestrial Radar Interferometry (TRI) and GNSS. Ocean tides are predominantly diurnal but horizontal GNSS displacements oscillate also semi-diurnally. The oscillations are strongest in the ice shelf and tidal signatures decay near-linearly in the TRI data over >10 km upstream of the grounding line. Tidal flexing is observed >6 km upstream of the grounding line including cm-scale uplift. Tidal grounding line migration is small and <40 % of the ice thickness. The frequency doubling of horizontal displacements relative to the ocean tides is consistent with variable ice-shelf buttressing demonstrated with a visco-elastic Maxwell model. Taken together, this supports previously hypothesized flexural ice softening in the grounding-zone through tides and offers new observational constraints for the role of ice rheology in ice-shelf buttressing. Related Publication: Drews, R., Wild, C. T., Marsh, O. J., Rack, W., Ehlers, T. A., Neckel, N., & Helm, V. (2021). Grounding-zone flow variability of Priestley Glacier, Antarctica, in a diurnal tidal regime. Geophysical Research Letters, 48, e2021GL093853. https://doi.org/10.1029/2021GL093853 GET DATA: https://doi.org/10.1594/PANGAEA.935707

  • These data were aquired with a Terrestrial Radar Interferometer overlooking the grounding zone of Priestley Glacier, Antarctica. The time series contains differential interferograms with a 12h temporal baseline covering an approximately 8 day period in November 2018. Tidal modulation of ice streams and their adjacent ice shelves is a real-world experiment to understand ice-dynamic processes. We observe the dynamics of Priestley Glacier, Antarctica, using Terrestrial Radar Interferometry (TRI) and GNSS. Ocean tides are predominantly diurnal but horizontal GNSS displacements oscillate also semi-diurnally. The oscillations are strongest in the ice shelf and tidal signatures decay near-linearly in the TRI data over >10 km upstream of the grounding line. Tidal flexing is observed >6 km upstream of the grounding line including cm-scale uplift. Tidal grounding line migration is small and <40 % of the ice thickness. The frequency doubling of horizontal displacements relative to the ocean tides is consistent with variable ice-shelf buttressing demonstrated with a visco-elastic Maxwell model. Taken together, this supports previously hypothesized flexural ice softening in the grounding-zone through tides and offers new observational constraints for the role of ice rheology in ice-shelf buttressing. Time series of line-of-sight flowfields averaged over approximately three hours. Data were taken with a Terrestrial Radar Interferometer in November 2018 at the grounding zone of Priestley Glacier, Antarctica – The Zip Archive contains 288 Geotiff in South polar stereographic projection – Each raster has 4027 x 4746 entries – The file name details the approximately 3h time inverval of aquisition with Stack_YYYYMMDD_HHMMSS_YYYYMMDD_HHMMSS marking the beginning and end of the time interval, respectively. – The line of sight velocities are given in meters per year Related Publication: Drews, R., Wild, C. T., Marsh, O. J., Rack, W., Ehlers, T. A., Neckel, N., & Helm, V. (2021). Grounding-zone flow variability of Priestley Glacier, Antarctica, in a diurnal tidal regime. Geophysical Research Letters, 48, e2021GL093853. https://doi.org/10.1029/2021GL093853 GET DATA: https://doi.org/10.1594/PANGAEA.935702

  • The structural glaciology and movement of the Taylor Glacier, was investigated over several seasons (98-01) by excavating a tunnel in the right side of the Taylor Glacier, 1.5km upstream of the terminus, to provide access to basal ice and the glacier substrate. Basal ice was sampled and analysed for concentration of base cations and chlorides present. Strain arrays and precision dial gauges were installed to monitor movement and deformation of the tunnel and ice velocity. In situ samples of clean and debris bearing glacier ice shear samples were taken from the basal ice to test in a laboratory. The tunnel was re-cut 1.3km upstream of the terminus in the 99-00 season as the other had closed in, with strain arrays and plumb lines installed and basal ice re-sampled. Ice cores were sampled for mechanical tests from the tunnel and the glacier surface. Ice cores were taken from the ice margin of Lake Bonny. Strain arrays and plumb lines were resurveyed and the deformation of the tunnel measured. This metadata record represents: - Data set from Taylor Glacier tunnel - Photographs of tunnel excavation - Video of tunnel excavation Further details are provided at: Fitzsimons, S., Samyn, D., & Lorrain, R (2024). Deformation, strength and tectonic evolution of basal ice in Taylor Glacier, Antarctica. Journal of Geophysical Research: Earth Surface, 129, e2023JF007456. https://doi.org/10.1029/2023JF007456 GET DATA: https://doi.org/10.5281/zenodo.8232003