Evidence for Obliquity Forcing of Glacial Termination II
Evidence for Obliquity Forcing of Glacial Termination II
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DOI：
10.1126/science.1170371
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发表时间：
2009-09-18
期刊：
影响因子：
56.9
通讯作者：
Isola, I.
中科院分区：
文献类型：
--
作者：
Drysdale, R. N.;Hellstrom, J. C.;Isola, I.
北半球高纬度夏季日照强度的变化，主要受春分岁差的驱动，被广泛认为控制了晚更新世冰川终止的时间。然而，最近有人提出，地球倾角的变化可能是一个更重要的机制。我们提出了一个新的基于洞穴的北大西洋海洋年代学，表明第二次冰期终止（终止II）开始于距今141,000 +/- 2500年前，太早了，无法用北半球夏季日照来解释，但与地球倾角的变化一致。我们的记录显示，终端I和II被三个倾角周期分开，它们开始于几乎相同的倾角阶段。
Variations in the intensity of high-latitude Northern Hemisphere summer insolation, driven largely by precession of the equinoxes, are widely thought to control the timing of Late Pleistocene glacial terminations. However, recently it has been suggested that changes in Earth's obliquity may be a more important mechanism. We present a new speleothem-based North Atlantic marine chronology that shows that the penultimate glacial termination (Termination II) commenced 141,000 +/- 2500 years before the present, too early to be explained by Northern Hemisphere summer insolation but consistent with changes in Earth's obliquity. Our record reveals that Terminations I and II are separated by three obliquity cycles and that they started at near-identical obliquity phases.