Persistent influence of obliquity on ice age terminations since the Middle Pleistocene transition
Persistent influence of obliquity on ice age terminations since the Middle Pleistocene transition
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DOI：
10.1126/science.aaw1114
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发表时间：
2020-03-13
期刊：
影响因子：
56.9
通讯作者：
Fallick, Anthony E.
中科院分区：
文献类型：
--
作者：
Bajo, Petra;Drysdale, Russell N.;Fallick, Anthony E.
对过去 64 万年冰川终止的辐射测年表明，地球气候进动的节奏是一致的，每个冰期-间冰期跨越四到五个周期，类似于 2 万年。然而，由于缺乏对更早的更新世终止的确切年龄估计，这使得测试岁差强迫的持久性的尝试陷入困境。我们将意大利洞穴记录与北大西洋数据结合起来，以铀铅年代学为基础，表明所谓的10万年世界的前两次冰消期被两个倾角周期分开，每次终止都始于相同的高倾角阶段，但在岁差的相反阶段。对过去数百万年中 11 次放射性定年终止的评估表明，倾角不仅对它们的起始而且对它们的持续时间产生持续的影响。
Radiometric dating of glacial terminations over the past 640,000 years suggests pacing by Earth's climatic precession, with each glacial-interglacial period spanning four or five cycles of similar to 20,000 years. However, the lack of firm age estimates for older Pleistocene terminations confounds attempts to test the persistence of precession forcing. We combine an Italian speleothem record anchored by a uranium-lead chronology with North Atlantic ocean data to show that the first two deglaciations of the so-called 100,000-year world are separated by two obliquity cycles, with each termination starting at the same high phase of obliquity, but at opposing phases of precession. An assessment of 11 radiometrically dated terminations spanning the past million years suggests that obliquity exerted a persistent influence on not only their initiation but also their duration.