Fault reactivation in the central Indian Ocean and the rheology of oceanic lithosphere
Fault reactivation in the central Indian Ocean and the rheology of oceanic lithosphere
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DOI：
10.1038/344855a0
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发表时间：
1990-04
期刊：
影响因子：
64.8
通讯作者：
J. Bull;R. Scrutton
中科院分区：
文献类型：
--
作者：
J. Bull;R. Scrutton
印度洋中部盆地的板块内变形是一个众所周知的偏离板块构造公理的例子：刚性板块的变形集中在板块边界。本文给出的多道地震反射剖面显示，印度洋中部沉积物中的高角度逆断层穿过地壳，并可能延伸至上地幔。这些断裂在基底的倾角约为~ 40°，我们认为这是由扩张中心形成的原有断裂的再活化引起的，这与扩张中心现在形成的断裂的地震分布和震源机制是一致的。这种类型的变形，加上对地幔岩石圈大地震的观测，表明海洋岩石圈的脆性破坏可能在脆/韧性转变附近成核并通过地壳传播。
THE intraplate deformation in the central Indian Ocean basin is a well-known example of a deviation from an axiom of plate tectonics: that of rigid plates with deformation concentrated at plate boundaries. Here we present multichannel seismic reflection profiles which show that high-angle reverse faults in the sediments of the central Indian Ocean extend through the crust and possibly into the uppermost mantle. The dip of these faults, which we believe result from the reactivation of pre-existing faults formed at the spreading centre, is ˜40° in the basement, which is consistent with the distribution and focal mechanisms of earthquakes on faults now forming at spreading centres. This style of deformation, coupled with the observation of large earthquakes in the mantle lithosphere, indicates that brittle failure of the oceanic lithosphere may nucleate in the vicinity of the brittle/ductile transition and propagate through the crust.