Dynamics of core formation and equilibration by negative diapirism
Dynamics of core formation and equilibration by negative diapirism
复制标题
负底辟作用下核心形成和平衡的动力学
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
P. Tackley
中科院分区：
文献类型：
--
作者：
H. Samuel;P. Tackley
我们通过负底辟作用动态研究地核形成过程中的时间和金属 - 硅酸盐平衡过程。利用三维轴对称几何形状的数值模拟，我们追踪富铁底辟在粘性硅酸盐地幔中的下沉过程。我们进行了一项参数研究，其中考虑了剪切加热以及几种粘性流变学，并对其进行了系统变化。推导出了底辟下沉速度以及底辟周围硅酸盐熔体产生和分布的一般标度律。利用这些标度律，我们表明，半径约为1 - 100米的金属底辟在穿过部分熔融的硅酸盐地幔下沉时，能够在地球化学约束所建议的时间尺度内达到化学平衡。因此，负底辟作用可对地核形成过程中的金属 - 硅酸盐平衡过程有显著贡献。
We investigate dynamically the timing and metal‐silicate equilibration processes during core formation by negative diapirism. Using numerical modeling in 3‐D axisymmetric geometry, we follow the sinking of iron‐rich diapirs through a viscous silicate mantle. We carried out a parameter study in which shear heating as well as several viscous rheologies are considered and systematically varied. General scaling laws are derived for the diapir sinking velocity as well as for the silicate melt generation and distribution around the diapir. Using these scaling laws, we show that metal diapirs of a radius ∼1–100 m, sinking through a partially molten silicate mantle can chemically equilibrate within the timescales suggested by geochemical constraints. Therefore negative diapirism can contribute significantly to metal‐silicate equilibration processes during core formation.