Longitudinal confinement of geomagnetic reversal paths as a possible sedimentary artefact
Longitudinal confinement of geomagnetic reversal paths as a possible sedimentary artefact
复制标题
地磁反转路径的纵向限制作为可能的沉积人工制品
作者：
C. Langereis;A. V. Hoof;P. Rochette
在地球磁场的大量反转期间，虚拟地磁极（VGP）的位置似乎显示出对美洲大陆或对极大陆的显著限制1，2，尽管有人认为这种限制在统计上没有充分的约束3。还有人指出，4在其他地球物理观测中也出现了同样的经度带，例如外核的流体运动模式和下地幔中地震速度较高的区域，这表明存在因果关系。在这里，我们表明，纵向约束的VGP可以产生平滑的非对极稳定的方向（只是）之前和之后的地磁反转，因为在沉积物中的剩磁采集过程的过滤效果。这种非反足性的起源仍然是不确定的，必须保持推测，直到更多的逆转记录，包括足够长的前和后过渡的时间间隔。
THE positions of the virtual geomagnetic pole (VGP) during a large number of reversals of the Earth's magnetic field seem to show a remarkable confinement to longitudes over the Americas or to antipodal longitudes1,2, although it has been argued that this confinement is statistically insufficiently constrained3. It has also been pointed out4 that the same bands of longitude appear in other geophysical observations, such as the pattern of fluid motion in the outer core and regions of higher seismic velocities in the lower mantle, suggesting a causal relationship. Here we show that longitudinal confinement of VGPs can arise from the smoothing of non-antipodal stable directions (just) before and after a geomagnetic reversal, because of the filtering effect of the remanence acquisition process in sediments. The origin of this non-antipodality is still uncertain and must remain speculative until more reversal records become available that include sufficiently long pre- and post-transitional intervals.