Age stratigraphy in the East Antarctic Ice Sheet inferred from radio-echo sounding horizons

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).

Five decades of radioglaciology

“…Challenges remain in combining disparate datasets, conditioning data for comparison with modeling and utilizing radiometric, interferometric and polarimetric information in modeling (e.g. Hindmarsh and others, 2009; Schroeder and others, 2016c; Castelletti and others, 2017, 2019; Winter and others, 2017, 2019; Chu and others, 2018b; Jordan and others, 2019). Finally, data–model interaction is a two-way street: testable hypotheses produced by theory and models may suggest new observational targets or provide new reasons to tap the rich radioglaciological archive (e.g.…”

“…In Antarctica, no such large-scale synthesis has been undertaken, but the SCAR AntArchitecture project has the potential to address this critical gap. Several studies have successfully linked isochrones between deep ice-core sites: the interior Antarctic ice-core sites are now linked from Dome Concordia through Vostok to Dome Argus, and Dome Fuji has been linked to the EPICA-DML (European Project for Ice Coring in Antarctica Dronning Maud Land) ice-core site (Cavitte and others, 2016; Winter and others, 2019). These efforts will play a key role in identifying optimal drill sites for the Oldest Ice (ice older than 1.5 million years, Fischer and others, 2013).…”

Englacial Architecture and Age‐Depth Constraints Across the West Antarctic Ice Sheet

“…This demonstrates a previously unknown utility of the PASIN archive, which covers large parts of West and East Antarctica, for IRH tracing. With reference to the ability to trace IRHs over dynamic ice, almost all previous englacial tracing in Antarctica performed to date has been along or around ice divides, where ice dynamics has not disrupted flow or introduced discontinuities (e.g., Cavitte et al, 2016;Siegert et al, 1998;Siegert et al, 2005;Siegert & Hodgkins, 2000;Winter et al, 2019). Siegert et al (2005) were able to trace some IRHs across the Siple Coast Ice Streams from the 1970s SPRI-NSF-TUD surveys, but few were traceable across IMIS.…”

Radar-Derived Internal Structure and Basal Roughness Characterization along a Traverse from Zhongshan Station to Dome A, East Antarctica

“…The low ILCI of other layers may be associated with changes in bed conditions and ice fabrics [16,32,34]. The internal layers in some areas of GSM are discontinuous because of recent or former megadunes and surface erosion by wind erosion or sublimation [5,53,54]. This may be the reason for the relatively low ILCI of the shallow layers in Zone E.…”

“…Among them, the internal stratigraphy that can be traced over a long distance represents the same age layers (isochrones). Therefore, radar observations can provide not only information about the ice age [4,5], ice rheology [6][7][8], and ice conditions [9][10][11], but also constraints and tests for ice-sheet models [12][13][14], all of which play an irreplaceable role in the assessment of ice sheet mass balance and ice dynamics [15].…”