Seismic Imaging of Thickened Lithosphere Resulting From Plume Pulsing Beneath Iceland.
Seismic Imaging of Thickened Lithosphere Resulting From Plume Pulsing Beneath Iceland.
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DOI：
10.1029/2018gc007501
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发表时间：
2018-06
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影响因子：
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通讯作者：
Armitage JJ
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文献类型：
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作者：
Rychert CA;Harmon N;Armitage JJ
随着海底年龄的增长，海洋板块会传导冷却并下沉。随着年龄的增长，钢板也会变厚，而热点可能会导致变薄。然而，两者都存在争议，并取决于盘子的定义方式。确定板的厚度以及控制它的过程已被证明是具有挑战性的。我们使用S - to - P （Sp）接收函数来成像冰岛下方一个强大的、持续的LAB，在那里大西洋中脊与带有假设的脉动热异常的羽流相互作用。板块最厚，可达84±6公里，位于假设的较热羽流温度时期形成的岩石圈下方，薄至61±6公里，位于较冷时期形成的区域下方。我们进行了地球动力学模拟，表明这些板块厚度与热岩石圈不一致。相反，羽流温度升高的时期可能会增加融化的深度，导致更深的枯竭和脱水，并形成更厚的板块。这表明板块厚度是由板块形成的条件决定的。S - to - P接收函数图像冰岛下方横向变化的岩石圈厚度岩石圈厚度在假设的羽流通量或温度较大的时期形成的区域最大。地球动力学和波形建模表明，板块下方有熔体，厚度由形成条件决定
Ocean plates conductively cool and subside with seafloor age. Plate thickening with age is also predicted, and hot spots may cause thinning. However, both are debated and depend on the way the plate is defined. Determining the thickness of the plates along with the process that governs it has proven challenging. We use S‐to‐P (Sp) receiver functions to image a strong, persistent LAB beneath Iceland where the mid‐Atlantic Ridge interacts with a plume with hypothesized pulsating thermal anomaly. The plate is thickest, up to 84 ± 6 km, beneath lithosphere formed during times of hypothesized hotter plume temperatures and as thin as 61 ± 6 km beneath regions formed during colder intervals. We performed geodynamic modeling to show that these plate thicknesses are inconsistent with a thermal lithosphere. Instead, periods of increased plume temperatures likely increased the melting depth, causing deeper depletion and dehydration, and creating a thicker plate. This suggests plate thickness is dictated by the conditions of plate formation. S‐to‐P receiver functions image laterally variable lithospheric thickness beneath Iceland Lithospheric thickness is greatest in regions formed during hypothesized periods of greater plume flux or temperature Geodynamic and waveform modeling suggest melt beneath the plate, with thickness dictated by the conditions of formation