An Explanation for Earth's Long-Term Rotational Stability
An Explanation for Earth's Long-Term Rotational Stability
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DOI：
10.1126/science.275.5298.372
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发表时间：
1997-01
期刊：
影响因子：
56.9
通讯作者：
M. Richards;Y. Ricard;C. Lithgow‐Bertelloni;G. Spada;R. Sabadini
中科院分区：
文献类型：
--
作者：
M. Richards;Y. Ricard;C. Lithgow‐Bertelloni;G. Spada;R. Sabadini
古地磁数据显示，在过去1亿年里，古地磁和热点参照系之间的运动距离不到∼1,000公里--即真正的极移，这意味着地球的自转轴一直非常稳定。这种长期的旋转稳定性可以用新生代和晚中生代板块构造运动大尺度模式的缓慢变化来解释，前提是俯冲的岩石圈是对流产生的地幔密度不均匀的主要组成部分。因此，没有必要引用其他机制，如旋转凸起的缓慢重新调整，来解释观察到的低真极游动率。
Paleomagnetic data show less than ∼1000 kilometers of motion between the paleomagnetic and hotspot reference frames—that is, true polar wander—during the past 100 million years, which implies that Earth's rotation axis has been very stable. This long-term rotational stability can be explained by the slow rate of change in the large-scale pattern of plate tectonic motions during Cenozoic and late Mesozoic time, provided that subducted lithosphere is a major component of the mantle density heterogeneity generated by convection. Therefore, it is unnecessary to invoke other mechanisms, such as sluggish readjustment of the rotational bulge, to explain the observed low rate of true polar wander.