scholarly journals Review comments for Age stratigraphy in the East Antarctic Ice Sheet inferred from radio echo sounding horizons

2019 ◽  
Author(s):  
Marie G. P. Cavitte
2020 ◽  
Vol 61 (81) ◽  
pp. 162-175
Author(s):  
Olaf Eisen ◽  
Anna Winter ◽  
Daniel Steinhage ◽  
Thomas Kleiner ◽  
Angelika Humbert

AbstractBasal motion of ice sheets depends in part on the roughness and material properties of the subglacial bed and the occurrence of water. To date, basal motion represents one of the largest uncertainties in ice-flow models. It is that component of the total flow velocity that can change most rapidly and can, therefore, facilitate rapid variations in dynamic behaviour. In this study, we investigate the subglacial properties of the East Antarctic Ice Sheet by statistically analysing the roughness of the bed topography, inferred from radio-echo sounding measurements. We analyse two sets of roughness parameters, one derived in the spatial and the other in the spectral domain, with two roughness parameters each. This enables us to compare the suitability of the four roughness parameters to classify the subglacial landscapes below the ice sheet. We further investigate the relationship of the roughness parameters with observed surface flow velocity and modelled basal temperatures of the ice sheet. We find that one of the roughness parameters, the Hurst exponent derived in the spatial domain, coincides with the thermal condition at the base of the ice sheet for slow flow velocities and varies with flow velocity.


2018 ◽  
Author(s):  
Anna Winter ◽  
Daniel Steinhage ◽  
Timothy T. Creyts ◽  
Thomas Kleiner ◽  
Olaf Eisen

Abstract. The East Antarctic Ice Sheet contains a wealth of information that can be extracted from its internal architecture such as distribution of age, past flow features and surface and basal properties. Airborne radar surveys can sample this stratigraphic archive across broad areas. Here, we identify and trace key horizons across several radar surveys to obtain the stratigraphic information. We transfer the age-depth scales from ice cores to intersecting radar data. We then propagate these age scales across the ice sheet using the high fidelity continuity of the radar horizons. In Dronning Maud Land, including Dome Fuji, we mapped isochrones with ages of 38 ka and 74 ka. In the central region of East Antarctica around Dome Concordia, Vostok, and Dome Argus, we use isochrone ages of 38 ka, 48 ka, 90 ka, and 161 ka. Taking together both regions, we provide isochrone depths traced along a combined profile length of more than 40,000 km and discuss uncertainties of the obtained stratigraphy, as well as factors important to consider for further expansion. This dataset the most extensive distribution of internal horizons in East Antarctica to date. The isochrone depths are available on PANGAEA: https://doi.pangaea.de/10.1594/PANGAEA.895528.


2019 ◽  
Vol 11 (3) ◽  
pp. 1069-1081 ◽  
Author(s):  
Anna Winter ◽  
Daniel Steinhage ◽  
Timothy T. Creyts ◽  
Thomas Kleiner ◽  
Olaf Eisen

Abstract. The East Antarctic Ice Sheet contains a wealth of information that can be extracted from its internal architecture such as distribution of age, past flow features, and surface and basal properties. Airborne radar surveys can sample this stratigraphic archive across broad areas. Here, we identify and trace key horizons across several radar surveys to obtain the stratigraphic information. We transfer the age–depth scales from ice cores to intersecting radar data. We then propagate these age scales across the ice sheet using the high fidelity continuity of the radar horizons. In Dronning Maud Land, including Dome Fuji, we mapped isochrones with ages of 38 and 74 ka. In the central region of East Antarctica around Dome Concordia, Vostok and Dome Argus, we use isochrone ages of 38, 48, 90 and 161 ka. Taking together both regions, we provide isochrone depths traced along a combined profile length of more than 40 000 km and discuss uncertainties of the obtained stratigraphy, as well as factors important to consider for further expansion. This data set is the most extensive distribution of internal horizons in East Antarctica to date. The isochrone depths presented in this study are available on PANGAEA (https://doi.org/10.1594/PANGAEA.895528; Winter et al., 2018).


2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Reed P. Scherer ◽  
Robert M. DeConto ◽  
David Pollard ◽  
Richard B. Alley

2017 ◽  
Vol 159 ◽  
pp. 88-102 ◽  
Author(s):  
Nicole A. Bader ◽  
Kathy J. Licht ◽  
Michael R. Kaplan ◽  
Christine Kassab ◽  
Gisela Winckler

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