Constraints on lithosphere net rotation and asthenospheric viscosity from global mantle flow models and seismic anisotropy
Constraints on lithosphere net rotation and asthenospheric viscosity from global mantle flow models and seismic anisotropy
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DOI：
10.1029/2009gc002970
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发表时间：
2010-05-13
影响因子：
3.5
通讯作者：
Behn, Mark D.
中科院分区：
文献类型：
--
作者：
Conrad, Clinton P.;Behn, Mark D.
虽然全球分析表明地球岩石圈的平均向西旋转与深部地幔（如地幔）有关的表面特征。例如，在一个实施例中，热点轨迹），岩石圈漂移的速率是不确定的，尽管它对全球地球动力学的重要性。我们使用一个全球性的粘性流模型来预测软流圈的各向异性计算的地幔流场的线性组合驱动的相对板块运动，地幔密度的不均匀性，向西岩石圈旋转。通过比较SKS分裂观测和面波层析成像推断的大洋地区软流圈各向异性的晶格择优取向的预测，我们将上地幔的绝对粘度（与其他约束条件一致，为0.5-1.0 × 10（21）Pa·s）与净旋转速率和软流圈相对于上地幔粘度的降低同时约束。对于一个比上地幔的粘性小10倍的软流圈，我们发现全球净旋转必须是
Although an average westward rotation of the Earth's lithosphere is indicated by global analyses of surface features tied to the deep mantle (e. g., hot spot tracks), the rate of lithospheric drift is uncertain despite its importance to global geodynamics. We use a global viscous flow model to predict asthenospheric anisotropy computed from linear combinations of mantle flow fields driven by relative plate motions, mantle density heterogeneity, and westward lithosphere rotation. By comparing predictions of lattice preferred orientation to asthenospheric anisotropy in oceanic regions inferred from SKS splitting observations and surface wave tomography, we constrain absolute upper mantle viscosity (to 0.5-1.0 x 10(21) Pa s, consistent with other constraints) simultaneously with net rotation rate and the decrease in the viscosity of the asthenosphere relative to that of the upper mantle. For an asthenosphere 10 times less viscous than the upper mantle, we find that global net rotation must be