Persistent influence of precession on northern ice sheet variability since the early Pleistocene
Persistent influence of precession on northern ice sheet variability since the early Pleistocene
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DOI：
10.1126/science.abm4033
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发表时间：
2022-05-27
期刊：
影响因子：
56.9
通讯作者：
Levay, Leah
中科院分区：
文献类型：
--
作者：
Barker, Stephen;Starr, Aidan;Levay, Leah
在近似100万年前（Ma）之前，全球冰量的变化主要是由岁差的变化决定的;然而，岁差的作用仍然没有得到解决。使用北大西洋冰漂流跨越过去170万年的记录，我们发现，在一个给定的冰川周期内（反映冰盖扩张）的冰漂流的发病始终发生在减少的冰密度的时间，而大规模的冰浪费（消融）事件始终与岁差的最小值。此外，我们的研究结果表明，普遍存在的岁差驱动的质量消耗事件和冰川终止之间的关联是中晚更新世的一个明显特征。在此之前（增加），单是冰化就足以结束一个冰期循环，然后随着北方冰盖向南延伸，冰化作用失去了主导地位。
Prior to similar to 1 million years ago (Ma), variations in global ice volume were dominated by changes in obliquity; however, the role of precession remains unresolved. Using a record of North Atlantic ice rafting spanning the past 1.7 million years, we find that the onset of ice rafting within a given glacial cycle (reflecting ice sheet expansion) consistently occurred during times of decreasing obliquity whereas mass ice wasting (ablation) events were consistently tied to minima in precession. Furthermore, our results suggest that the ubiquitous association between precession-driven mass wasting events and glacial termination is a distinct feature of the mid to late Pleistocene. Before then (increasing), obliquity alone was sufficient to end a glacial cycle, before losing its dominant grip on deglaciation with the southward extension of Northern Hemisphere ice sheets since similar to 1 Ma.