Geographical distribution of transitional VGPs: Evidence for non-zonal equatorial symmetry during the Matuyama-Brunhes geomagnetic reversal
Geographical distribution of transitional VGPs: Evidence for non-zonal equatorial symmetry during the Matuyama-Brunhes geomagnetic reversal
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过渡性 VGP 的地理分布：松山-布伦赫斯地磁反转期间非纬向赤道对称性的证据
DOI：
10.1016/0012-821x(91)90236-b
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发表时间：
1991
影响因子：
5.3
通讯作者：
B. Clement
中科院分区：
文献类型：
--
作者：
B. Clement
最近从大西洋部分的北方、赤道和南方纬度获得的松山-布鲁赫极性逆转的古地磁记录显示出相对于赤道的明显对称性。来自北方和南方半球中纬度站点（DSDP站点609和核心V16-58）的虚拟地磁极（VGP）路径几乎重合，向北跟踪通过美洲。VGP路径从赤道站点（ODP站点664）向北穿过东亚，几乎与其他两条路径对映。模拟结果表明，叠加一个h13几何上的反向轴向偶极子解释了赤道对称的意义上表现出这三个记录。这些结果是一致的大部分数据可从其他记录的极性转变，这表明过渡VGP在此反转往往下降沿着两个不同的纵向带。过渡性弱势群体的分组表明，逆转过程受到很强的地理控制。过渡VGP的纵向带与核幔边界历史地磁场径向分量中主要通量集中的位置之间存在明显的相关性[1]，这表明导致这些通量集中的过程可能影响了Matuyama-Brunhes过渡场的几何形状。
Paleomagnetic records of the Matuyama-Brunhes polarity reversal obtained recently from the northern, equatorial and southern latitudes of the Atlantic sector display a distinct symmetry with respect to the Equator. The virtual geomagnetic pole (VGP) paths from the mid-latitude sites in the northern and southern hemispheres (DSDP Site 609 and Core V16-58) are nearly coincident, tracking northward through the Americas. The VGP path from the equatorial site (ODP Site 664) tracks northward through eastern Asia, nearly antipodal to the other two paths. Modeling results indicate that superimposing an h13geometry onto a reversing axial dipole explains the sense of equatorial symmetry exhibited by these three records. These results are consistent with the bulk of the data available from other records of this polarity transition, suggesting that the transitional VGPs during this reversal tend to fall along two distinct longitudinal bands. The grouping of transitional VGPs suggests that there is a strong geographical control over the reversal process. An apparent correlation between the longitudinal bands of transitional VGPs and the location of the major flux concentrations in the radial component of the historical geomagnetic field at the core-mantle boundary [1] suggests that the processes which cause these flux concentrations may have influenced the geometry of the Matuyama-Brunhes transitional field.