Radiocarbon Levels in the Iceland Sea from 25–53 kyr and their Link to the Earth's Magnetic Field Intensity
Radiocarbon Levels in the Iceland Sea from 25–53 kyr and their Link to the Earth's Magnetic Field Intensity
复制标题
冰岛海 25-53 kyr 的放射性碳水平及其与地球磁场强度的联系
DOI：
10.1017/s0033822200030368
复制
发表时间：
2000
期刊：
影响因子：
8.3
通讯作者：
M. Sarnthein
中科院分区：
文献类型：
--
作者：
A. Voelker;P. Grootes;M. Nadeau;M. Sarnthein
本文通过气候记录与有孔虫N.利用冰岛海PS2644冰芯的14 C厚皮层，结合GISP 2冰芯的年代学资料，获得了11.4- 53.3kacalBP的80个海洋14 C刻度点。在27 ~ 54 ka cal BP之间，14 C/cal年龄差异的连续记录揭示了三个14 C浓度高度增加的时段与古磁场强度的低值相一致，其中两个时段归因于地磁Mono Lake和Laschamp偏移（33.5-34.5 ka cal BP，最大δ 14 C为550; 40.3-41.7 ka cal BP，最大δ 14 C为1215）。第三个最大值（海洋δ 14 C：755）在38 ka cal BP左右观察到，并归因于Laschamp偏移后的地磁强度最小值。在所有三个事件中，A14 C值迅速增加，最大值出现在各自地磁强度最小值的末尾。然而，在莫诺湖事件期间，如果与GRIP冰芯（瓦格纳等人，2000年）和其他记录中测量的36 Cl通量相比，我们的A14 C值似乎低估了大气水平。由于这一偏移与PS2644岩心的融水事件相吻合，因此低估可能是由南极洲储层年龄增加引起的。同样的效应也发生在38.5 - 40 ka cal BP，当Heinrich事件4的融水盖影响到南极记录时。
By correlating the climate records and radiocarbon ages of the planktonic foraminifera N. pachyderma(s) of deep-sea core PS2644 from the Iceland Sea with the annual-layer chronology of the GISP2 ice core, we obtained 80 marine 14C calibration points for the interval 11.4-53.3 ka cal BP. Between 27 and 54 ka cal BP the continuous record of 14C/cal age differences reveals three intervals of highly increased 14C concentrations coincident with low values of paleomagnetic field intensity, two of which are attributed to the geomagnetic Mono Lake and Laschamp excursions (33.5-34.5 ka cal BP with maximum 550 marine δ14C, and 40.3-41.7 ka cal BP with maximum 1215 marine δ14C, respectively). A third maximum (marine δ14C: 755) is observed around 38 ka cal BP and attributed to the geomagnetic intensity minimum following the Laschamp excursion. During all three events the A14C values increase rapidly with maximum values occurring at the end of the respective geomagnetic intensity minimum. During the Mono Lake Event, however, our A14C values seem to underestimate the atmospheric level, if compared to the 36Cl flux measured in the GRIP ice core (Wagner et al. 2000) and other records. As this excursion coincides with a meltwater event in core PS2644, the underestimation is probably caused by an increased planktonic reservoir age. The same effect also occurs from 38.5 to 40 ka cal BP when the meltwater lid of Heinrich Event 4 affected the planktonic record.