Steinberger Bernhard, Sutherland Rupert, O'Connell Richard J
Institute for Frontier Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
Nature. 2004 Jul 8;430(6996):167-73. doi: 10.1038/nature02660.
The bend in the Hawaiian-Emperor seamount chain is a prominent feature usually attributed to a change in Pacific plate motion approximately 47 Myr ago. However, global plate motion reconstructions fail to predict the bend. Here we show how the geometry of the Hawaiian-Emperor chain and other hotspot tracks can be explained when we combine global plate motions with intraplate deformation and movement of hotspot plumes through distortion by global mantle flow. Global mantle flow models predict a southward motion of the Hawaiian hotspot. This, in combination with a plate motion reconstruction connecting Pacific and African plates through Antarctica, predicts the Hawaiian track correctly since the date of the bend, but predicts the chain to be too far west before it. But if a reconstruction through Australia and Lord Howe rise is used instead, the track is predicted correctly back to 65 Myr ago, including the bend. The difference between the two predictions indicates the effect of intraplate deformation not yet recognized or else not recorded on the ocean floor. The remaining misfit before 65 Myr ago can be attributed to additional intraplate deformation of similar magnitude.
夏威夷-帝王海山链的弯曲是一个显著特征,通常被认为是大约4700万年前太平洋板块运动发生变化所致。然而,全球板块运动重建未能预测到这一弯曲。在此我们表明,当我们将全球板块运动与板内变形以及热点地幔柱因全球地幔流引起的扭曲而发生的移动相结合时,夏威夷-帝王海山链以及其他热点轨迹的几何形态是可以得到解释的。全球地幔流模型预测夏威夷热点有向南的移动。这与通过南极洲连接太平洋板块和非洲板块的板块运动重建相结合,自弯曲发生之日起能正确预测夏威夷轨迹,但在此之前预测该海山链位置偏西太远。但如果改用通过澳大利亚和豪勋爵海隆的重建,该轨迹能被正确追溯到6500万年前,包括弯曲部分。这两种预测之间的差异表明了尚未被认识到或未记录在海底的板内变形的影响。6500万年前之前剩余的偏差可归因于类似规模的额外板内变形。