Age and duration of Laschamp and Iceland Basin geomagnetic excursions in the South Atlantic Ocean
Age and duration of Laschamp and Iceland Basin geomagnetic excursions in the South Atlantic Ocean
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DOI：
10.1016/j.quascirev.2017.04.020
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发表时间：
2017-07
影响因子：
4
通讯作者：
J. Channell;N. V. Riveiros;J. Gottschalk;C. Waelbroeck;L. Skinner
中科院分区：
文献类型：
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作者：
J. Channell;N. V. Riveiros;J. Gottschalk;C. Waelbroeck;L. Skinner
根据放射性碳年代测定以及将海面温度记录与南极冰芯（EPICA）气温记录进行匹配，得出了拉尚和冰岛海盆从南大西洋洋中脊东侧（南纬44.15°，西经14.22°）偏移的新记录的年龄模型。Laschamp漂移的开始发生在南极同位素极大值（AIM）10期间，与格陵兰Interstadial 10期间的发生一致。拉尚号在AIM 9之前在格陵兰10号体育场结束。年龄模型的支持同步性的方向和相对paleointensity表现的Laschamp漂移在海洋核心EPICA 10 Be和硝酸盐通量的峰值。冰岛海盆的漂移与EPICA δD记录中记录的海洋同位素阶段（MIS）7a到MIS 6 e的转变的最后阶段同步。拉尚和冰岛海盆偏移的起始时间（此处定义为分量倾角>-40 °）分别为41.4 ka和190.0 ka，持续时间分别为1.1 kyr和1.35 kyr，尽管这些估计值取决于定义方向偏移的标准。通过与北大西洋Laschamp和冰岛海盆的漂移记录进行比较，根据格陵兰和南极冰芯的GICC 05和AICC 2012年龄模型的同步，这两次漂移在两个半球之间的百年时间尺度上是同步的。
Age models for new records of the Laschamp and Iceland Basin excursions from the eastern flank of the South Atlantic mid-ocean ridge (44.15°S, 14.22°W) are derived from radiocarbon dates, and from matching sea-surface temperature records to Antarctic (EPICA) air-temperature records from ice cores. The onset of the Laschamp excursion occurred during Antarctic Isotopic Maximum (AIM) 10, consistent with its occurrence during Greenland Interstadial 10. The end of the Laschamp excursion occurred prior to AIM 9 in Greenland Stadial 10. The age model is supported by synchroneity of directional and relative paleointensity manifestations of the Laschamp excursion in the marine core with peaks in EPICA10Be and nitrate flux. The Iceland Basin excursion is synchronous with the final phase of the transition from marine isotope stage (MIS) 7a to MIS 6e as recorded in the EPICA δD record. The onset of the Laschamp and Iceland Basin excursions, defined here by component inclinations >−40°, occurred at 41.4 ka and 190.0 ka, and durations are ∼1 kyr and ∼3.5 kyr, respectively, although these estimates depend on the criteria used to define the directional excursions. By comparison with Laschamp and Iceland Basin excursion records from the North Atlantic Ocean, the two excursions are synchronous at centennial timescales between the two hemispheres, based on synchronization of the GICC05 and AICC2012 age models for Greenland and Antarctic ice cores.