Brief Communication: New radar constraints support presence of ice older than 1.5 Ma at Little Dome C.

Lilien, David A.; Steinhage, Daniel; Taylor, Drew; Parrenin, Frédéric; Ritz, Catherine; Mulvaney, Robert ORCID: https://orcid.org/0000-0002-5372-8148; Martín, Carlos ORCID: https://orcid.org/0000-0002-2661-169X; Yan, Jie-Bang; O'Neill, Charles; Frezzotti, Massimo; Miller, Heinrich; Gogineni, Prasad; Dahl-Jensen, Dorthe; Eisen, Olaf. 2021 Brief Communication: New radar constraints support presence of ice older than 1.5 Ma at Little Dome C. [in special issue: Oldest Ice: finding and interpreting climate proxies in ice older than 700 000 years (TC/CP/ESSD inter-journal SI)] The Cryosphere, 15. 1881-1888. https://doi.org/10.5194/tc-15-1881-2021

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Official URL: https://tc.copernicus.org/articles/15/1881/2021/tc...

Abstract/Summary

The area near Dome C, East Antarctica, is thought to be one of the most promising targets for recovering a continuous ice-core record spanning more than a million years. The European Beyond EPICA consortium has selected Little Dome C, an area ~35 km south-east of Concordia Station, to attempt to recover such a record. Here, we present the results of the final ice-penetrating radar survey used to refine the exact drill site. These data were acquired during the 2019–2020 Austral summer using a new, multi-channel high-resolution VHF radar operating in the frequency range of 170–230 MHz. This new instrument is able to detect reflections in the near-basal region, where previous surveys were unable to trace continuous horizons. The radar stratigraphy is used to transfer the timescale of the EPICA Dome C ice core (EDC) to the area of Little Dome C, using radar isochrones dating back past 600 ka. We use these data to derive the expected depth–age relationship through the ice column at the now-chosen drill site, termed BELDC. These new data indicate that the ice at BELDC is considerably older than that at EDC at the same depth, and that there is about 375 m of ice older than 600 ka at BELDC. Stratigraphy is well preserved to 2565 m, below which there is a basal unit with unknown properties. A simple ice flow model tuned to the isochrones suggests ages likely reach 1.5 Ma near 2525 m, ~40 m above the basal unit and ~240 m above the bed, with sufficient resolution (14±1 ka m−1) to resolve 41 ka glacial cycles.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.5194/tc-15-1881-2021
ISSN:	19940416
Date made live:	16 Apr 2021 10:46 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/530070

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.5194/tc-15-1881-2021

ISSN:

19940416

Date made live:

16 Apr 2021 10:46 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/530070