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Global changes in intensity of the Earth's magnetic field during the past 800 kyr

机译:过去800年里地球磁场强度的全球变化

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摘要

Recent advances in palaeomagnetic and dating techniques have led to increasingly precise records of the relative intensity of the Earth's past magnetic field at numerous field sites. The compilation and analysis of these records can provide important constraints on changes in global magnetic field intensity and therefore on the Earth's geodynamo itself. A previous compilation for the past 200 kyr integrated 17 marine records into a composite curve, with the geomagnetic origin of the signal supported by an independent analysis of ~(10)Be production made on different cores. The persistence of long-term features in the Earth's magnetic intensity or the existence of long-term periodic changes cannot, however, be resolved in this relatively short tune span. Here we present the integration of 33 records of relative palaeointensity into a composite curve spanning the past 800 kyr. We find that the intensity of the Earth's dipole field has experienced large-amplitude variations over this time period with pronounced intensity minima coinciding with known excursions in field direction, reflecting the emergence of non-dipole components. No stable periodicity was found in our composite record and therefore our data set does not support the hypothesis that the Earth's orbital parameters have a direct and strong influence on the geodynamo.
机译:古磁学和测年技术的最新进展已导致越来越多的精确记录记录了过去许多地点的地球过去磁场的相对强度。这些记录的汇编和分析可以对全球磁场强度的变化,进而对地球的地球发电机本身提供重要的约束。过去200千千瓦的先前汇编将17条海洋记录整合成一条合成曲线,信号的地磁起源由对不同岩心的〜(10)Be产量的独立分析所支持。但是,在相对较短的声程中无法解决地球磁强度中长期特征的持久性或长期周期性变化的问题。在这里,我们介绍了将33条相对古老强度的记录整合为一条跨越800多年的复合曲线。我们发现,在此期间,地球偶极子场的强度经历了大幅度的变化,最小的强度与磁场方向上的已知偏移相吻合,反映了非偶极子分量的出现。在我们的综合记录中没有找到稳定的周期性,因此我们的数据集不支持地球轨道参数对大地发电机有直接而强烈影响的假设。

著录项

  • 来源
    《Nature》 |1999年第6733期|p.249-252|共4页
  • 作者单位
  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 自然科学总论;
  • 关键词

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