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An astronomically dated record of Earth’s climate and its predictability over the last 66 million years 期刊论文
Science, 2020
作者:  Thomas Westerhold;  Norbert Marwan;  Anna Joy Drury;  Diederik Liebrand;  Claudia Agnini;  Eleni Anagnostou;  James S. K. Barnet;  Steven M. Bohaty;  David De Vleeschouwer;  Fabio Florindo;  Thomas Frederichs;  David A. Hodell;  Ann E. Holbourn;  Dick Kroon;  Vittoria Lauretano;  Kate Littler;  Lucas J. Lourens;  Mitchell Lyle;  Heiko Pälike;  Ursula Röhl;  Jun Tian;  Roy H. Wilkens;  Paul A. Wilson;  James C. Zachos
收藏  |  浏览/下载：14/0  |  提交时间：2020/09/14
Ice retreat in Wilkes Basin of East Antarctica during a warm interglacial 期刊论文
NATURE, 2020, 583 (7817) : 554-+
作者:  T. Blackburn;  G. H. Edwards;  S. Tulaczyk;  M. Scudder;  G. Piccione;  B. Hallet;  N. McLean;  J. C. Zachos;  B. Cheney;  J. T. Babbe
收藏  |  浏览/下载：18/0  |  提交时间：2020/08/09

Uranium isotopes in subglacial precipitates from the Wilkes Basin of the East Antarctic Ice Sheet reveal ice retreat during a warm Pleistocene interglacial period about 400,000 years ago.


Efforts to improve sea level forecasting on a warming planet have focused on determining the temperature, sea level and extent of polar ice sheets during Earth'  s past interglacial warm periods(1-3). About 400,000 years ago, during the interglacial period known as Marine Isotopic Stage 11 (MIS11), the global temperature was 1 to 2 degrees Celsius greater(2)and sea level was 6 to 13 metres higher(1,3). Sea level estimates in excess of about 10 metres, however, have been discounted because these require a contribution from the East Antarctic Ice Sheet(3), which has been argued to have remained stable for millions of years before and includes MIS11(4,5). Here we show how the evolution of(234)U enrichment within the subglacial waters of East Antarctica recorded the ice sheet'  s response to MIS11 warming. Within the Wilkes Basin, subglacial chemical precipitates of opal and calcite record accumulation of(234)U (the product of rock-water contact within an isolated subglacial reservoir) up to 20 times higher than that found in marine waters. The timescales of(234)U enrichment place the inception of this reservoir at MIS11. Informed by the(234)U cycling observed in the Laurentide Ice Sheet, where(234)U accumulated during periods of ice stability(6)and was flushed to global oceans in response to deglaciation(7), we interpret our East Antarctic dataset to represent ice loss within the Wilkes Basin at MIS11. The(234)U accumulation within the Wilkes Basin is also observed in the McMurdo Dry Valleys brines(8-10), indicating(11)that the brine originated beneath the adjacent East Antarctic Ice Sheet. The marine origin of brine salts(10)and bacteria(12)implies that MIS11 ice loss was coupled with marine flooding. Collectively, these data indicate that during one of the warmest Pleistocene interglacials, the ice sheet margin at the Wilkes Basin retreated to near the precipitate location, about 700 kilometres inland from the current position of the ice margin, which-assuming current ice volumes-would have contributed about 3 to 4 metres(13)to global sea levels.


  
Palaeocene-Eocene Thermal Maximum prolonged by fossil carbon oxidation 期刊论文
NATURE GEOSCIENCE, 2019, 12 (1) : 54-+
作者:  Lyons, Shelby L.;  Baczynski, Allison A.;  Babila, Tali L.;  Bralower, Timothy J.;  Hajek, Elizabeth A.;  Kump, Lee R.;  Polites, Ellen G.;  Self-Trail, Jean M.;  Trampush, Sheila M.;  Vornlocher, Jamie R.;  Zachos, James C.;  Freeman, Katherine H.
收藏  |  浏览/下载：8/0  |  提交时间：2019/04/09