The influence of post-perovskite strength on the Earth's mantle thermal and chemical evolution
The influence of post-perovskite strength on the Earth's mantle thermal and chemical evolution
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DOI：
10.1016/j.epsl.2012.01.024
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发表时间：
2012-03-15
影响因子：
5.3
通讯作者：
Tosi, Nicola
中科院分区：
文献类型：
--
作者：
Samuel, Henri;Tosi, Nicola
通过数值模拟和简单的解析理论研究了后钙钛矿（ppv）粘度对地幔对流动力学和搅拌效率的影响，结果表明ppv的强度对对流动力学有显著的影响。弱ppv的存在增强了底部热边界层的热传递，导致更高的温度，更低的地幔粘度和相当大的对流速度。这导致了搅拌效率的显着增加，降低了PPV强度，至少一个数量级。此外，使用一个简单的参数化对流演化，包括PPV的影响，耦合到一个混合模型，我们表明，在地球地幔的长期历史，ppv的存在系统地产生了更热的热演化和更有效的对流搅拌。ppv强度对地幔搅拌效率的如此强烈的影响表明，在解释地球化学和地球物理观测结果时，必须考虑PPV相位的影响。(c)2012爱思唯尔有限公司版权所有。
We have investigated the influence of post-perovskite (ppv) viscosity on mantle convective dynamics and stirring efficiency, using numerical modeling and simple analytical theory.Our results show that the strength of ppv has a dramatic influence on convective dynamics. The presence of a weak ppv enhances heat transfer across the bottom thermal boundary layer, resulting in higher temperatures, lower mantle viscosities and considerably larger convective velocities. This leads to a significant increase in stirring efficiencies with decreasing the ppv strength, by at least one order of magnitude.In addition, using a simple parameterized convection evolution that includes the influence of ppv, coupled to a mixing model, we show that during the long term history of the Earth's mantle, the presence of ppv yields systematically hotter thermal evolution and more efficient convective stirring.Such a strong effect of ppv strength on mantle stirring efficiency suggests that the influence of ppv phase must be considered when interpreting both geochemical and geophysical observations. (c) 2012 Elsevier B.V. All rights reserved.