Compositional heterogeneity in the bottom 1000 kilometers of Earth's mantle: toward a hybrid convection model
Compositional heterogeneity in the bottom 1000 kilometers of Earth's mantle: toward a hybrid convection model
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DOI：
10.1126/science.283.5409.1885
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发表时间：
1999-03
期刊：
影响因子：
56.9
通讯作者：
R. Hilst;H. Kárason
中科院分区：
文献类型：
--
作者：
R. Hilst;H. Kárason
层析成像表明，俯冲岩石圈的板块可以深深地沉入地球的下地幔。因此，认为对流流动在660公里深处分层，并保留了相对原始的下地幔的观点是站不住脚的。然而，一系列地球物理证据表明，在地幔底部1000公里处可能存在成分不同的地幔域，因此对流隔离。这些区域的存在可能与局部铁富集和硅酸盐到氧化物的转化有关，这意味着地幔对流比传统的端元流动模型所设想的要复杂得多。
Tomographic imaging indicates that slabs of subducted lithosphere can sink deep into Earth's lower mantle. The view that convective flow is stratified at 660-kilometer depth and preserves a relatively pristine lower mantle is therefore not tenable. However, a range of geophysical evidence indicates that compositionally distinct, hence convectively isolated, mantle domains may exist in the bottom 1000 kilometers of the mantle. Survival of these domains, which are perhaps related to local iron enrichment and silicate-to-oxide transformations, implies that mantle convection is more complex than envisaged by conventional end-member flow models.