An 83 000-year-old ice core from Roosevelt Island, Ross Sea, Antarctica

oleh: J. E. Lee, E. J. Brook, N. A. N. Bertler, N. A. N. Bertler, C. Buizert, T. Baisden, T. Baisden, T. Blunier, V. G. Ciobanu, H. Conway, D. Dahl-Jensen, T. J. Fudge, R. Hindmarsh, E. D. Keller, F. Parrenin, J. P. Severinghaus, P. Vallelonga, E. D. Waddington, M. Winstrup

Format: Article
Diterbitkan: Copernicus Publications 2020-09-01

Deskripsi

<p>In 2013 an ice core was recovered from Roosevelt Island, an ice dome between two submarine troughs carved by paleo-ice-streams in the Ross Sea, Antarctica. The ice core is part of the Roosevelt Island Climate Evolution (RICE) project and provides new information about the past configuration of the West Antarctic Ice Sheet (WAIS) and its retreat during the last deglaciation. In this work we present the RICE17 chronology, which establishes the depth–age relationship for the top 754&thinsp;m of the 763&thinsp;m core. RICE17 is a composite chronology combining annual layer interpretations for 0–343&thinsp;m <span class="cit" id="xref_paren.1">(<a href="#bib1.bibx109">Winstrup et al.</a>, <a href="#bib1.bibx109">2019</a>)</span> with new estimates for gas and ice ages based on synchronization of <span class="inline-formula">CH<sub>4</sub></span> and <span class="inline-formula"><i>δ</i><sup>18</sup>O</span><span class="inline-formula"><sub>atm</sub></span> records to corresponding records from the WAIS Divide ice core and by modeling of the gas age–ice age difference.</p> <p>Novel aspects of this work include the following: (1) an automated algorithm for multiproxy stratigraphic synchronization of high-resolution gas records; (2) synchronization using centennial-scale variations in methane for pre-anthropogenic time periods (60–720&thinsp;m, 1971&thinsp;CE to 30&thinsp;ka), a strategy applicable for future ice cores; and (3) the observation of a continuous climate record back to <span class="inline-formula">∼65</span>&thinsp;ka providing evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.</p>