Apparent and true polar wander and the geometry of the geomagnetic field over the last 200 Myr
Apparent and true polar wander and the geometry of the geomagnetic field over the last 200 Myr
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DOI：
10.1029/2000jb000050
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发表时间：
2002-11-01
影响因子：
3.9
通讯作者：
Courtillot, V
中科院分区：
文献类型：
--
作者：
Besse, J;Courtillot, V
[1]我们已经构建了新的视极移路径（APWP）的主要板块在过去的200万年。更新的运动学模型和选定的古地磁数据使我们能够构建一个主APWP。一个持久的四极矩的3%的偶极子在过去的200万年的顺序建议。对比了古地磁和热点APW，提出了“真极移”（TPW）的新定义。在固定的大西洋和印度热点的假设下，我们证实，TPW是情节，（准）停顿的时期交替与TPW（在白垩纪）更快的时期。这些周期的典型持续时间大约为数千万年，快速轨道期间的漂移率大约为30至50 km/Myr。建议过去2亿年的总TPW约为30。我们没有发现令人信服的证据，情节的超快TPW，如最近提出的一些作者。在过去的1.3亿年的TPW推导出的热点轨道和古地磁数据在印度-大西洋半球与独立的确定太平洋板块的比较支持的想法，一阶，TPW是一个真正的全球地球动力学特征。与数值模拟估计的TPW的比较表明，所有目前的模式仍然未能在一定程度上占TPW速度的观测值和观察到的停顿和轨道的继承。
[1] We have constructed new apparent polar wander paths (APWPs) for major plates over the last 200 Myr. Updated kinematic models and selected paleomagnetic data allowed us to construct a master APWP. A persistent quadrupole moment on the order of 3% of the dipole over the last 200 Myr is suggested. Paleomagnetic and hot spot APW are compared, and a new determination of "true polar wander'' (TPW) is derived. Under the hypothesis of fixed Atlantic and Indian hot spots, we confirm that TPW is episodic, with periods of (quasi) standstill alternating with periods of faster TPW (in the Cretaceous). The typical duration of these periods is on the order of a few tens of millions of years with wander rates during fast tracks on the order of 30 to 50 km/Myr. A total TPW of some 30 is suggested for the last 200 Myr. We find no convincing evidence for episodes of superfast TPW such as proposed recently by a number of authors. Comparison over the last 130 Myr of TPW deduced from hot spot tracks and paleomagnetic data in the Indo-Atlantic hemisphere with an independent determination for the Pacific plate supports the idea that, to first order, TPW is a truly global feature of Earth dynamics. Comparison with numerical modeling estimates of TPW shows that all current models still fail to some extent to account for the observed values of TPW velocity and for the succession of standstills and tracks which is observed.