Widespread volcanism in the Greenland-North Atlantic region explained by the Iceland plume
Widespread volcanism in the Greenland-North Atlantic region explained by the Iceland plume
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DOI：
10.1038/s41561-018-0251-0
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发表时间：
2019-01-01
影响因子：
18.3
通讯作者：
Torsvik, Trond H.
中科院分区：
文献类型：
--
作者：
Steinberger, Bernhard;Bredow, Eva;Torsvik, Trond H.
在经典概念中，热点轨迹是板块在固定的地幔柱上方移动时形成的一列火山。与这一概念不同的是，格陵兰岛和北大西洋地区的板内火山活动在广大区域内同时发生，尤其在约6000万年前，与热点轨迹毫无相似之处。在此，我们表明，尽管如此，这种火山活动大多仍可仅由冰岛地幔柱与海底扩张脊、全球地幔流以及厚度变化极大的岩石圈（地球最外层的刚性层）相互作用来解释。根据新的高分辨率层析成像推断，格陵兰岛中部有一条东西向的岩石圈变薄走廊，可能是在9000万到6000万年前格陵兰岛在冰岛地幔柱上方向西移动时形成的。我们的数值地球动力学模型展示了地幔柱物质如何可能在这条走廊以及格陵兰岛东西两侧的区域聚集。大约6200万年前在格陵兰岛两侧同时开始的与地幔柱相关的火山活动，可能是在由于大陆裂谷和海底扩张导致岩石圈足够薄的地方和时间发生的，可能是在地幔柱到达岩石圈底部很久之后。
In the classical concept, a hotspot track is a line of volcanics formed as a plate moves over a stationary mantle plume. Defying this concept, intraplate volcanism in Greenland and the North Atlantic region occurred simultaneously over a wide area, particularly around 60 million years ago, showing no resemblance to a hotspot track. Here, we show that most of this volcanism can nonetheless be explained solely by the Iceland plume interacting with seafloor spreading ridges, global mantle flow and a litho-sphere (the outermost rigid layer of the Earth) with strongly variable thickness. An east-west corridor of thinned lithosphere across central Greenland, as inferred from new, highly resolved tomographic images, could have formed as Greenland moved westward over the Iceland plume between 90 and 60 million years ago. Our numerical geodynamic model demonstrates how plume material may have accumulated in this corridor and in areas east and west of Greenland. Simultaneous plume-related volcanic activities starting about 62 million years ago on either side of Greenland could occur where and when the lithosphere was thin enough due to continental rifting and seafloor spreading, possibly long after the plume reached the base of the lithosphere.