Evidence for glaciation in the Northern Hemisphere back to 44 Ma from ice-rafted debris in the Greenland Sea
Evidence for glaciation in the Northern Hemisphere back to 44 Ma from ice-rafted debris in the Greenland Sea
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DOI：
10.1016/j.epsl.2007.09.045
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发表时间：
2008-01
影响因子：
5.3
通讯作者：
A. Tripati;R. Eagle;A. Morton;J. Dowdeswell;Katie L. Atkinson;Y. Bahé;C. Dawber;E. Khadun;Ruth M.H. Shaw;O. Shorttle;L. Thanabalasundaram
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文献类型：
--
作者：
A. Tripati;R. Eagle;A. Morton;J. Dowdeswell;Katie L. Atkinson;Y. Bahé;C. Dawber;E. Khadun;Ruth M.H. Shaw;O. Shorttle;L. Thanabalasundaram
广泛接受的北半球冰期开始的年龄估计在200万至1500万年前（Ma）之间。然而，最近的研究表明，冰川开始的日期可能要早得多。我们报道了格陵兰海~ 44 ~ 30 Ma沉积物中冰筏碎屑（IRD）的存在，这是中始新世至早渐新世期间北大西洋冰川作用的证据。详细的沉积学证据表明，该地区的冰川一直延伸到海平面，从而形成了冰山。IRD可能来自潮汐冰川、小冰盖和/或大陆冰盖。
The widely accepted age estimate for the onset of glaciation in the Northern Hemisphere ranges between 2 and 15 million years ago (Ma). However, recent studies indicate the date for glacial onset may be significantly older. We report the presence of ice-rafted debris (IRD) in ∼44 to 30 Ma sediments from the Greenland Sea, evidence for glaciation in the North Atlantic during the Middle Eocene to Early Oligocene. Detailed sedimentological evidence indicates that glaciers extended to sea level in the region, allowing icebergs to be produced. IRD may have been sourced from tidewater glaciers, small ice caps, and/or a continental ice sheet.