类地行星热物理条件与热演化影响因素分析——以火星地幔热柱演化为例

发布时间：2019-01-07 08:26

【摘要】：太阳系内类地行星具有相似的岩石层包围金属核的圈层结构,在行星幔的热演化历史起源方面具有同时性和同源性,并且都在早期变形重力位能加热的基础上随放射性热能衰减而冷却。但是,由于半径、密度、粘度以及表层构造属性等物理条件的差异,其热演化历史各具特色。依据基本的热对流和热传导方程,我们计算分析了类地行星热物理条件差异对行星幔热演化历史的影响。计算表明,类地行星热演化的早期,行星幔热对流是主要的散热方式。半径较大的行星表面热流密度大,平均散热量也大。半径较小的行星内部温差小,粘滞系数高,对流能力低,提早进入传导散热状态,且传导散热的岩石层也比大行星厚。不同边界层热物理条件下,类地行星幔热演化历史会分别出现逐渐冷却的平稳式、包含热柱上涌的波动式、行星幔幕次翻转的周期式等特点不同的热演化过程。火星内部曾经存在的地幔热柱构造与火星地幔热动力学演化过程密切相关。我们从火星地幔热动力学演化模型出发,定量计算与地幔热柱构造演化相关的地幔热动力学演化特征,通过三维球壳数值模拟,研究了火星地幔热演化历史上可能存在的热柱活动造成的火星热演化历史的非单调变化,火星地幔对流环结构随时间的演变方式,以及与边界相关的地幔热柱对火星地形的影响。
[Abstract]:Earth-like planets in the solar system have a similar lithospheric ring structure surrounding the core of the metal, and are of simultaneous and homology in the historical origin of the thermal evolution of the planetary mantle. Both of them are cooled with the decay of radioactive heat energy on the basis of early deformation gravity potential energy heating. However, its thermal evolution history has its own characteristics due to the difference of physical conditions such as radius, density, viscosity and surface tectonic properties. Based on the basic thermal convection and heat conduction equations, we calculate and analyze the influence of the difference of geo-planetary thermo-physical conditions on the thermal evolution history of the planetary mantle. The results show that the thermal convection of the mantle is the main heat dissipation mode in the early stage of the thermal evolution of the terrestrial planets. The larger radius of the planet surface heat flux, the average heat loss is also large. The inner temperature difference of the planet with small radius is small, the viscosity coefficient is high, the convection ability is low, the planet enters the heat conduction state early, and the lithosphere with the conduction heat dissipation is thicker than the big planet. Under different boundary layer thermophysical conditions, the thermal evolution history of planetary like mantle will be gradually cooled, which includes the fluctuation of upwelling heat plume and the periodic mode of planetary mantle curtain subturnover. The mantle thermal plume in Mars is closely related to the thermal evolution of the Martian mantle. Based on the Martian mantle thermodynamics evolution model, the characteristics of mantle thermal dynamics evolution related to mantle thermal plume tectonic evolution are quantitatively calculated, and the three-dimensional spherical crust numerical simulation is carried out. The nonmonotonic variation of the thermal evolution history of Mars caused by the possible thermal plume activity in the Martian mantle and the evolution of the convective ring structure of the mantle over time are studied. And the influence of the mantle plume related to the boundary on the topography of Mars.
【作者单位】：中国科学院大学中国科学院计算地球动力学重点实验室;
【基金】：国家自然科学基金项目(编号:41174085) 中国科学院创新团队项目(编号:KZZD-EW-TZ-19) 中国科学院战略性先导科技专项(编号:XDA1103010102)资助
【分类号】：P185.3

【共引文献】