High-resolution lithosphere viscosity and dynamics revealed by magnetotelluric imaging
High-resolution lithosphere viscosity and dynamics revealed by magnetotelluric imaging
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DOI：
10.1126/science.aaf6542
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发表时间：
2016-09
期刊：
影响因子：
56.9
通讯作者：
Lijun Liu;D. Hasterok
中科院分区：
文献类型：
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作者：
Lijun Liu;D. Hasterok
准确的粘度结构是真实地模拟岩石圈动力学的关键。在这里，我们报告了一个试图推断有效的岩石圈粘度从高分辨率大地电磁（MT）调查在美国西部。MT领域的导电流体的存在下的高灵敏度，使其成为一个有前途的代理确定整个岩石圈的机械强度变化。我们展示了从电阻率近似的粘性结构如何产生地球动力学模型，该模型成功预测了短波长表面地形、岩石圈变形和近代火山活动下的地幔上涌。我们进一步表明，这种粘度是物理上一致的，更好地约束比来自实验室为基础的流变学。我们的结论是MT成像提供了一个实用的观测约束定量的大陆岩石圈的动态演化。
An accurate viscosity structure is critical to truthfully modeling lithosphere dynamics. Here, we report an attempt to infer the effective lithospheric viscosity from a high-resolution magnetotelluric (MT) survey across the western United States. The high sensitivity of MT fields to the presence of electrically conductive fluids makes it a promising proxy for determining mechanical strength variations throughout the lithosphere. We demonstrate how a viscosity structure, approximated from electrical resistivity, results in a geodynamic model that successfully predicts short-wavelength surface topography, lithospheric deformation, and mantle upwelling beneath recent volcanism. We further show that this viscosity is physically consistent with and better constrained than that derived from laboratory-based rheology. We conclude that MT imaging provides a practical observational constraint for quantifying the dynamic evolution of the continental lithosphere.