DOI: 10.1038/s41561-020-0623-0
论文题名: Coupled Southern Ocean cooling and Antarctic ice sheet expansion during the middle Miocene
作者: Leutert T.J. ; Auderset A. ; Martínez-García A. ; Modestou S. ; Meckler A.N.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2020
卷: 13, 期: 9 起始页码: 634
结束页码: 639
语种: 英语
英文关键词: atmosphere-ocean coupling
; biomarker
; climate variation
; cooling
; expansion
; Miocene
; planktonic foraminifera
; proxy climate record
; reconstruction
; sea surface temperature
; temperature effect
; Antarctic Ice Sheet
; Antarctica
; Southern Ocean
英文摘要: The middle Miocene climate transition (~14 million years ago) was characterized by a dramatic increase in the volume of the Antarctic ice sheet. The driving mechanism of this transition remains under discussion, with hypotheses including circulation changes, declining carbon dioxide in the atmosphere and orbital forcing. Southern Ocean records of planktic foraminiferal Mg/Ca have previously been interpreted to indicate a cooling of 6–7 °C and a decrease in salinity that preceded Antarctic cryosphere expansion by up to ~300,000 years. This interpretation has led to the hypothesis that changes in meridional heat and vapour transport along with an early thermal isolation of Antarctica from extrapolar climates played a fundamental role in triggering ice growth. Here we revisit the middle Miocene Southern Ocean temperature evolution using clumped isotope and lipid biomarker temperature proxies. Our records indicate that the Southern Ocean cooling and the associated salinity decrease occurred in phase with the expansion of the Antarctic ice sheet. We demonstrate that the timing and magnitude of the Southern Ocean temperature change seen in previous reconstructions can be explained if we consider pH as an additional, non-thermal, control on foraminiferal Mg/Ca ratios. Therefore, our new dataset challenges the view of a thermal isolation of Antarctica preceding ice sheet expansion, and suggests a strong coupling between Southern Ocean conditions and Antarctic ice volume in times of declining atmospheric carbon dioxide. © 2020, The Author(s), under exclusive licence to Springer Nature Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169638
Appears in Collections: 气候变化与战略
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作者单位: Bjerknes Centre for Climate Research and Department of Earth Science, University of Bergen, Bergen, Norway; Max Planck Institute for Chemistry, Mainz, Germany; Geological Institute, ETH Zurich, Zurich, Switzerland; Max Planck Institute for Chemistry, Mainz, Germany
Recommended Citation:
Leutert T.J.,Auderset A.,Martínez-García A.,et al. Coupled Southern Ocean cooling and Antarctic ice sheet expansion during the middle Miocene[J]. Nature Geoscience,2020-01-01,13(9)