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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:21/0  |  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.


  
Electron Vorticity Indicative of the Electron Diffusion Region of Magnetic Reconnection 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (12) : 6287-6296
作者:  Hwang, K. -J.;  Choi, E.;  Dokgo, K.;  Burch, J. L.;  Sibeck, D. G.;  Giles, B. L.;  Goldstein, M. L.;  Paterson, W. R.;  Pollock, C. J.;  Shi, Q. Q.;  Fu, H.;  Hasegawa, H.;  Gershman, D. J.;  Khotyaintsev, Y.;  Torbert, R. B.;  Ergun, R. E.;  Dorelli, J. C.;  Avanov, L.;  Russell, C. T.;  Strangeway, R. J.
收藏  |  浏览/下载:8/0  |  提交时间:2019/11/26
magnetic reconnection  electron diffusion region  electron vorticity  reconnection  magnetotail  current sheet  
Thin Current Sheets of Sub-ion Scales observed by MAVEN in the Martian Magnetotail 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (12) : 6214-6222
作者:  Grigorenko, E. E.;  Zelenyi, L. M.;  DiBraccio, G.;  Ermakov, V. N.;  Shuvalov, S. D.;  Malova, H. V.;  Popov, V. Y.;  Halekas, J. S.;  Mitchell, D. L.;  Dubinin, E.
收藏  |  浏览/下载:5/0  |  提交时间:2019/11/26
Martian magnetotail  Current Sheet  
Solar Wind Directional Change Triggering Flapping Motions of the Current Sheet: MMS Observations 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (1) : 64-70
作者:  Wang, G. Q.;  Zhang, T. L.;  Wu, M. Y.;  Schmid, D.;  Cao, J. B.;  Volwerk, M.
收藏  |  浏览/下载:7/0  |  提交时间:2019/04/09
flapping motion  current sheet  solar wind velocity  field-aligned current  
Effects of Cross-Sheet Density and Temperature Inhomogeneities on Magnetotail Reconnection 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (1) : 28-36
作者:  Lu, San;  Artemyev, A. V.;  Angelopoulos, V.;  Pritchett, P. L.;  Runov, A.
收藏  |  浏览/下载:11/0  |  提交时间:2019/04/09
magnetic reconnection  magnetotail current sheet  
An Electron-Scale Current Sheet Without Bursty Reconnection Signatures Observed in the Near-Earth Tail 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2018, 45 (10) : 4542-4549
作者:  Wang, Rongsheng;  Lu, Quanming;  Nakamura, Rumi;  Baumjohann, Wolfgang;  Huang, Can;  Russell, Christopher T.;  Burch, J. L.;  Pollock, Craig J.;  Gershman, Dan;  Ergun, R. E.;  Wang, Shui;  Lindqvist, P. A.;  Giles, Barbara
收藏  |  浏览/下载:9/0  |  提交时间:2019/04/09
magnetotail  current sheet  magnetic reconnection  
Intense Cross-Tail Field-Aligned Currents in the Plasma Sheet at Lunar Distances 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2018, 45 (10) : 4610-4617
作者:  Xu, Sixue;  Runov, Andrei;  Artemyev, Anton;  Angelopoulos, Vassilis;  Lu, Quanming
收藏  |  浏览/下载:9/0  |  提交时间:2019/04/09
Magnetosphere  Magnetotail  Plasma Sheet  Current Sheet  
Does a Local B-Minimum Appear in the Tail Current Sheet During a Substorm Growth Phase? 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2018, 45 (6) : 2566-2573
作者:  Sergeev, V. A.;  Gordeev, E. I.;  Merkin, V. G.;  Sitnov, M. I.
收藏  |  浏览/下载:7/0  |  提交时间:2019/04/09
tail current sheet stability  energetic particle precipitation  remote sensing  substorm growth phase  solar electrons  
Mercury's cross-tail current sheet: Structure, X-line location and stress balance 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2017, 44 (2)
作者:  Poh, Gangkai;  Slavin, James A.;  Jia, Xianzhe;  Raines, Jim M.;  Imber, Suzanne M.;  Sun, Wei-Jie;  Gershman, Daniel J.;  DiBraccio, Gina A.;  Genestreti, Kevin J.;  Smith, Andy W.
收藏  |  浏览/下载:6/0  |  提交时间:2019/04/09
Mercury  cross-tail current sheet  stress balance  Near-Mercury Neutral Line  magnetotail structure  
Electron currents supporting the near-Earth magnetotail during current sheet thinning 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2017, 44 (1) : 43596
作者:  Artemyev, A. V.;  Angelopoulos, V.;  Liu, J.;  Runov, A.
收藏  |  浏览/下载:1/0  |  提交时间:2019/04/09
magnetotail  substorm  current sheet