Predictability of Rayleigh-Number and Continental-Growth Evolution of a Dynamic Model of the Earth’s Mantle
Predictability of Rayleigh-Number and Continental-Growth Evolution of a Dynamic Model of the Earth’s Mantle
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地幔动态模型瑞利数和大陆生长演化的可预测性
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
R. Hendel
中科院分区：
文献类型：
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作者：
U. Walzer;R. Hendel
我们通过数值求解质量、动量、能量、角动量的平衡方程以及 238U-206Pb、235U-207Pb、232Th-208Pb 和 40K-40Ar 对的原子数的四个总和的平衡方程来计算地幔的热和化学演化模型。我们得出了主要地球化学储层的大理石饼分布，并表明即使在当今的地幔中，尽管有 4500 Ma 的热对流，这些储层也可以单独存在。尽管我们没有规定大陆的数量、大小、形式和分布，但我们得出了当今可信的大陆和海洋分布。本文的重点是现象的可预测部分和随机部分的问题。尽管对流流动模式和海洋高原的化学分异是耦合的，但随时间变化的瑞利数 Ra t 的演变是相对较好可预测的，并且 Ra t (t) 曲线的随机部分很小。关于大陆总质量的幼年增长率，只有在进化的第一个时期才有可能进行预测。后来，大陆增长事件的分布变得越来越随机。独立于不同的个体运行，我们的模型表明，当今大陆的总质量不是在地球热演化开始时的单一过程中产生的，而是在地质时间过程中的偶发分布过程中产生的。这与观察相符。第 4 节介绍了可扩展性和性能方面的结果。
We compute a model of thermal and chemical evolution of the Earth’s mantle by numerically solving the balance equations of mass, momentum, energy, angular momentum and of four sums of the number of atoms of the pairs 238U-206Pb, 235U-207Pb, 232Th-208Pb, and 40K-40Ar. We derive marble-cake distributions of the principal geochemical reservoirs and show that these reservoirs can separately exist even in a present-day mantle in spite of 4500 Ma of thermal convection. We arrive at plausible present-day distributions of continents and oceans although we did not prescribe number, size, form, and distribution of continents. The focus of this paper is the question of predictable and stochastic portions of the phenomena. Although the convective flow patterns and the chemical differentiation of oceanic plateaus are coupled, the evolution of time-dependent Rayleigh number, Ra t , is relatively well predictable and the stochastic parts of the Ra t (t)-curves are small. Regarding the juvenile growth rates of the total mass of the continents, predictions are possible only in the first epoch of the evolution. Later on, the distribution of the continental-growth episodes is increasingly stochastic. Independently of the varying individual runs, our model shows that the total mass of the present-day continents is not generated in a single process at the beginning of the thermal evolution of the Earth but in episodically distributed processes in the course of geological time. This is in accord with observation. Section 4 presents results on scalability and performance.
影响因子：
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作者：
Walzer;R. Hendel
通讯作者：
R. Hendel