论文标题

带有构造过渡的行星热演化模型

Planetary thermal evolution models with tectonic transitions

论文作者

O'Neill, Craig

论文摘要

热历史计算提供了对行星内部演变的重要见解,但结合了它们所代表的系统的简化动力学。行星内饰典型地结合了复杂的流变,粘性分层,侧向异质性和时间延迟,这些过程传统上不受参数化方法的代表。在这里,我们开发了行星演化的数值模型,结合了地球内部的物理复杂性,并使用它们来生成基于统计的NU-RA量表。这些封装了构造过渡,几何形状和深度依赖性流变学和时间敏感性的主要影响。我们发现一个指数$β$ 〜0.26最能描述不断发展的移动盖系统的NU-RA关系,而停滞系统的$β$ 〜0.12。在哈迪斯期间,与时间相关的俯冲的系统之间的$β$在约0.26之间,当诸如影响促进构造的外部因素促进了构造,而在古细胞期间,该系统由长时间的静止状态主导,并且由长时间的静止状态和系统驱动的系统受外部锻炼所驱动的系统(例如,由于地球历史的前100myr的影响,都可能会出现更多的展览。我们还发现RA(主要取决于地幔温度)和约200-300myr的NU(标准化表面热流)之间的时间段,这表明地幔热构型与其表面表现之间存在显着延迟。这些结果为陆地系外行星的构造,火山和大气进化的快速表征提供了一种方法。

Thermal history calculations provide important insights into the interior evolution of planets, but incorporate simplified dynamics from the systems they represent. Planetary interiors typical incorporate complex rheologies, viscous layering, lateral heterogeneities, and time delays in processes, which have not been traditionally represented by parameterised approaches. Here we develop numerical models for planetary evolution, incorporating the physical complexity of Earth's interior, and use them to generate statistically-based Nu-Ra scalings. These encapsulate the main effects of tectonic transitions, geometry, and depth-dependent rheology, and time-sensitivity. We find an exponent $β$ of ~0.26 best describes the Nu-Ra relationship for evolving mobile lid systems, and $β$ ~0.12 for stagnant-lid systems. Systems with time dependent subduction have $β$ varying between ~0.26 during the Hadean, when external factors such as impacts facilitate tectonics, to ~0.12 during the Archaean, when the system is dominated by long periods of quiescence, and systems driven by external forcings (eg. due to impacts in the first 100Myr of Earth's history) may exhibit much higher exponents. We also find a time-lag between Ra (which primarily depends on mantle temperature) and Nu (normalised surface heat flow) of around 200-300Myr, suggesting a significant delay between mantle thermal configuration, and its surface manifestation. These results provide an approach for the rapid characterisation of tectonic, volcanic, and atmospheric evolution of terrestrial exoplanets.

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