Geomagnetic intensity and C-14 abundance in the atmosphere and ocean during the past 50kyr

被引:113
作者
Laj, C
Mazaud, A
Duplessy, JC
机构
[1] Ctr. des Faibles Radioactivites, Laboratoire Mixte CNRS/CEA, Gif-sur-Yvette
[2] Ctr. des Faibles Radioactivites, Laboratoire Mixte CNRS-CEA, 91198 Gif-sur-Yvette Cedex, Avenue de la Terrasse
关键词
D O I
10.1029/96GL02152
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
We have used a new sedimentary record of geomagnetic field intensity, combined with published volcanic data, to examine the extent to which geomagnetic changes have affected C-14 production in the past. The production record was then converted into an atmospheric Delta(14)C signal using a 4-box model of past oceanic circulation. The results indicate that changes in geomagnetic field intensity account for at least 80% of the Delta(14)C shift documented by published U-Th data, which are of the order of 500 per mil with respect to a constant production hypothesis. Model simulations show that changes in past oceanic circulation account for only +/- 100 per mil of Delta(14)C variation, which is within the uncertainty of the geomagnetic correction. In terms of dating, these results show that the radiocarbon ages have to be shifted by 2 to 3.5 kyr towards older ages during the 20-40 ka interval.
引用
收藏
页码:2045 / 2048
页数:4
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