Oblique rift opening revealed by reoccurring magma injection in central Iceland.
Oblique rift opening revealed by reoccurring magma injection in central Iceland.
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DOI：
10.1038/ncomms12352
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发表时间：
2016-08-05
影响因子：
16.6
通讯作者：
Jónsson S
中科院分区：
文献类型：
--
作者：
Ruch J;Wang T;Xu W;Hensch M;Jónsson S
几个世纪以来，伸展赤字在不同的板块边界积累起来，并在裂谷事件中反复消失，伴随着岩浆侵入和瞬间的米级变形。然而，有关瞬时近场形变的信息很少被捕捉到，这阻碍了对裂谷机制和演化的理解。在这里，我们展示了受先前存在的裂缝和两个世纪的伸展赤字积累影响的裂谷事件中斜向裂谷打开的新证据。这一事件起源于Bárçarbunga火山口，并导致了冰岛200年来最大的玄武岩喷发。结果表明，张开初期伴随着左旋切变，随着张开的增加而停止。我们的结果表明，预先存在的裂缝在控制发散板块边界处的斜向裂隙开放方面起着关键作用。在裂谷事件期间，很少观察到分叉板块边界的变形，因此约束很差。Ruch et al.展示了冰岛Báráarbunga火山口斜裂缝的证据，这是近200年来观察到的最大的玄武岩喷发之一
Extension deficit builds up over centuries at divergent plate boundaries and is recurrently removed during rifting events, accompanied by magma intrusions and transient metre-scale deformation. However, information on transient near-field deformation has rarely been captured, hindering progress in understanding rifting mechanisms and evolution. Here we show new evidence of oblique rift opening during a rifting event influenced by pre-existing fractures and two centuries of extension deficit accumulation. This event originated from the Bárðarbunga caldera and led to the largest basaltic eruption in Iceland in >200 years. The results show that the opening was initially accompanied by left-lateral shear that ceased with increasing opening. Our results imply that pre-existing fractures play a key role in controlling oblique rift opening at divergent plate boundaries. Deformation at divergent plate boundaries during rifting events is rarely observed and therefore poorly constrained. Ruch et al. show evidence of an oblique rift opening at the Bárðarbunga caldera, Iceland, which was one of the largest basaltic eruptions observed in the last 200 years