Geological, tomographic, kinematic and geodynamic constraints on the dynamics of sinking slabs
Geological, tomographic, kinematic and geodynamic constraints on the dynamics of sinking slabs
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DOI：
10.1016/j.jog.2013.10.006
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发表时间：
2014-01-01
影响因子：
2.3
通讯作者：
Heine, C.
中科院分区：
文献类型：
--
作者：
Butterworth, N. P.;Talsrna, A. S.;Heine, C.
我们使用地球动力学模型与强加的板块速度来测试一个特定的板块运动模型对替代地震层析成像模型的基础上的俯冲的正演模拟的历史。我们利用三个替代出版的参考框架：一个混合移动热点古地磁，一个混合移动热点真极漂移校正古地磁，和俯冲参考框架，板块模型，包括俯冲带的纵向位移相匹配的俯冲体积成像的P波层析成像，以评估模型最好地预测现今地幔结构相比，地震层析成像和体积派生的俯冲历史。地球动力学模型表明，应用于俯冲参考框架的古纵向校正导致北美和东亚下方的下地幔板物质积累到断层摄影成像向西10-15度，而混合模型开发的物质偏移2-9度。然而，俯冲参考框架地球动力学模型产生的板状物质下的特提斯域符合板卷成像断层扫描，而混合参考框架模型不，这表明区域古纵向校正需要约束板的位置。我们使用我们的模型来测试推断板下沉率在地幔集中在良好的约束区域。我们得出一个全球平均板下沉率为13 +/- 3毫米/年，结合地质数据和运动学重建的俯冲板在地幔中的图像的开始和停止的年龄。我们的全球平均板块下沉速率与地幔对流模型所暗示的15-20毫米/年速率重叠，该模型使用的下地幔粘度比上地幔高100倍。(C)2013爱思唯尔有限公司保留所有权利。
We use geodynamic models with imposed plate velocities to test the forward-modeled history of subduction based on a particular plate motion model against alternative seismic tomography models. We utilize three alternative published reference frames: a hybrid moving hotspot-palaeomagnetic, a hybrid moving hotspot-true polar wander corrected-palaeomagnetic, and a Subduction Reference Frame, a plate model including longitudinal shifts of subduction zones by matching subduction volumes imaged by P-wave tomography, to assess which model best predicts present day mantle structure compared with seismic tomography and volumetrically derived subduction history. Geodynamic modeling suggests paleo-longitudinal corrections applied to the Subduction Reference Frame result in lower mantle slab material beneath North America and East Asia accumulating up to 10-15 degrees westward of that imaged by tomography, whereas the hybrid models develop material offset by 2-9 degrees. However, the Subduction Reference Frame geodynamic model produces slab material beneath the Tethyan Domain coinciding with slab volumes imaged by tomography, whereas the hybrid reference frame models do not, suggesting regional paleo-longitudinal corrections are required to constrain slab locations. We use our models to test inferred slab sinking rates in the mantle focusing on well-constrained regions. We derive a globally averaged slab-sinking rate of 13 +/- 3 mm/yr by combining the ages of onset and cessation of subduction from geological data and kinematic reconstructions with images of subducted slabs in the mantle. Our global average slab-sinking rate overlaps with the 15-20 mm/yr rate implied by mantle convection models using a lower mantle viscosity 100 times higher than the upper mantle. (C) 2013 Elsevier Ltd. All rights reserved.