A 65 Ma palaeomagnetic pole for the Pacific plate from the skewness of magnetic anomalies 27r-31
A 65 Ma palaeomagnetic pole for the Pacific plate from the skewness of magnetic anomalies 27r-31
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从磁异常 27r-31 的偏斜度看太平洋板块的 65 Ma 古磁极
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
R. Gordon
中科院分区：
文献类型：
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作者：
G. Acton;R. Gordon
苏建民，马建民，王瑞宇。利用海底扩张磁异常27r-31的偏度确定太平洋板块晚马斯特里赫特-早古新世古磁极的修正。我们使用数值实验来估计磁剖面中以前没有分析偏度信息的潜在信息。结果表明，Murray断裂带和Galapagos断裂带之间的剖面最有用，因为在该区域，假设的古磁极位置变化很小，预测的剩磁有效倾角值也非常不同。此外，这些数据会将磁极约束在先前数据约束最差的方向上。使用来自17个剖面的50个偏度估计，我们计算出一个约束良好的极点，该极点与从其他类型的具有相似年龄的数据中计算出的极点一致。这些数据包括一个海山古磁极、来自两个海底脊的有效倾角、来自海底玄武岩的无方位岩心和深海沉积物中的活塞岩心确定的古纬度、来自赤道沉积相的两个古赤道以及来自磁力线的振幅数据。结合所有数据，我们确定了一个最适合太平洋板块的65 Ma古磁极，位于71.6'N,7.9 ' 8。新极点的95%置信度椭圆为-50 / /，长半轴为2.9英寸，向北顺时针75英寸，短半轴为1.8英寸
S U M M A R Y We use the skewness of seafloor-spreading magnetic anomalies 27r-31 to determine a revised Late Maastrichtian-early Palaeocene palaeomagnetic pole for the Pacific plate. We used numerical experiments to estimate the potential information in magnetic profiles that had not been previously analysed for skewness information. The results indicated that profiles obtained between the Murray and Galapagos fracture zones would be the most useful because in this region very different values of remanent magnetic effective inclination are predicted for small changes in the assumed palaeomagnetic pole position. Furthermore, these data would constrain the pole in the direction most poorly constrained by prior data. Using 50 skewness estimates from 17 profiles, we compute a well-constrained pole that agrees with a pole computed from other types of data with similar ages. These other data include a seamount palaeomagnetic pole, effective inclinations from two submarine ridges, palaeolatitudes determined from azimuthally unoriented cores of submarine basalt and from a piston core in deep-sea sediments, two palaeo-equators from equatorial sediment facies, and amplitude data from magnetic lineations. Combining all the data, we determine a best-fit 65 Ma palaeomagnetic pole for the Pacific plate that is focated at 71.6'N,7.9"8. The 95 per cent confidence ellipse for the new pole, a 2.9" major semiaxis oriented 75" clockwise of north and a 1.8" minor semiaxis, is -50 per