Core‐mantle boundary topography estimated from numerical simulations of instantaneous mantle flow
Core‐mantle boundary topography estimated from numerical simulations of instantaneous mantle flow
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DOI：
10.1029/2008gc002008
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发表时间：
2008-07
期刊：
影响因子：
3.7
通讯作者：
Masaki Yoshida
中科院分区：
文献类型：
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作者：
Masaki Yoshida
核幔边界（CMB）地形估计从瞬时地幔流在三维球壳几何的数值模拟。地幔密度异常模型主要是由地震层析成像结果约束的地球动力学模型导出的。为了解释从最近的地震学结果推断的小（± 1.5 km）CMB地形起伏，地幔中的横向粘度变化，深部地幔中的成分密集堆，以及低粘度D“层都是数值模型所必需的。下地幔中的低粘度俯冲板块有助于降低高速区域下方的地形振幅（即，环太平洋带（Circum-Pacific Belt）密集桩的存在可能会导致局部地形凹陷，即使在低速区域（即，南太平洋和大西洋非洲区域）。
Core‐mantle boundary (CMB) topography is estimated from numerical simulations of instantaneous mantle flow in a three‐dimensional spherical shell geometry. Density anomaly models of the Earth's mantle are derived from geodynamic models constrained principally by seismic tomography results. To account for the small (±∼1.5 km) CMB topographic relief inferred from recent seismological results, lateral viscosity variations in the mantle, compositionally dense piles in the deep mantle, and a low‐viscosity D″ layer are all required for the numerical models. Low‐viscosity subducting slabs in the lower mantle serve to reduce the topographic amplitude below high‐velocity regions (i.e., the circum‐Pacific belt). The existence of dense piles may cause the local topographic depressions even below low‐velocity regions (i.e., the South Pacific and Atlantic Africa regions).