• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Geomagnetic field intensity, North Atlantic Deep Water circulation and atmospheric △~(14)C during the last 50 kyr
【24h】

Geomagnetic field intensity, North Atlantic Deep Water circulation and atmospheric △~(14)C during the last 50 kyr

机译：近50年来地磁场强度，北大西洋深水环流和大气△〜（14）C

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We present simulated records of past changes in the atmospheric △~(14)C for the last 50 kyr due to changes in geomagnetic field intensity and in the strength of the North Atlantic Deep Water (NADW). A new geomagnetic record was used, largely based on the NAPIS-75 record [Laj et al., Phil. Trans. R. Soc. London A 358 (2000) 1009-1025] which has been extended for the 0-20 kyr interval using archeomagnetic and volcanic data. Past changes of the NADW were derived from a mineral magnetic study of the cores used in the construction of NAPIS-75. Two box models of different complexity (4 and 17 boxes) were used to simulate the carbon cycle. Calculated records of △~(14)C are consistent with experimental determinations for the last 24 kyr. For older ages, the records calculated with variable oceanic circulation conditions reach values as high as 600% (with an average of 500%) between 20 and 40 kyr with maxima around 21, 30 and 38 kyr (GISP2 age model), while low values are observed prior to 42 kyr. Although large inconsistencies in experimental data preclude precise comparison, the average record simulated with the 17-box model is overall consistent with the Icelandic Sea record [Voelker et al., Radiocarbon 40 (1998) 517-534; 42 (2000)437-452], except for the extremely high peak observed in this record at 40.5 kyr. On the other hand, the results recently reported from a stalagmite recovered from a submerged cave in the Bahama [Beck et al., Science 292 (2001) 2453-2458] are inconsistent with all our model simulations. In the 20-45 kyr interval, the improved geomagnetic record combined with the new NADW profile allows us to give a modeled evaluation of the relative contribution of these factors to changes in atmospheric △~(14)C. The average simulation provides a first order modeled correction for conventional radiocarbon ages older than 25 kyr for which no calibration curve is available as yet.
机译：我们提供了过去50年来由于地磁场强度和北大西洋深水（NADW）强度变化而导致的过去△〜（14）C大气变化的模拟记录。使用了一个新的地磁记录，该记录主要基于NAPIS-75记录[Laj等，Phil。反式R. Soc。伦敦A 358（2000）1009-1025]，已使用地磁和火山数据将其扩展为0-20年。 NADW的过去更改来自对NAPIS-75构造中使用的磁芯的矿物磁研究。使用两个不同复杂度的盒子模型（4个和17个盒子）来模拟碳循环。 △〜（14）C的计算记录与最近24个月的实验结果一致。对于较老的年龄，在不同的海洋环流条件下计算得出的记录值在20至40年之间高达600％（平均为500％），最大值在21、30和38年左右（GISP2年龄模型），而较低在42年前观测到。尽管实验数据中的大量不一致之处无法进行精确比较，但是使用17-box模型模拟的平均记录总体上与冰岛海记录一致[Voelker等，Radiocarbon 40（1998）517-534; 42（2000）437-452]，但在该记录中在40.5 kyr处观察到极高的峰值。另一方面，最近从巴哈马（Bahama）的一个水下洞穴中回收的石笋报告的结果[Beck等，科学292（2001）2453-2458]与我们所有的模型模拟均不一致。在20-45年的时间间隔内，改进的地磁记录与新的NADW剖面相结合，使我们能够对这些因素对大气△〜（14）C变化的相对贡献进行模型评估。平均模拟为25 yry以上的传统放射性碳年龄提供了一阶建模校正，目前尚无校准曲线。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号