Influence of thermal stratification on the structure and evolution of
the Martian core.
Abstract
The apparent end of the internally generated Martian magnetic field at
3.6-4.1 Ga has been linked to insufficient core cooling. While the
dynamo cessation time is a key event in the Martian history, a large
range of solutions exist to satisfy this observation, limiting the
insight it provides on the Martian interior. We produce a suite of
models improving our understanding of the evolution of Mars in three
keys areas. Firstly, we account for thermal stratification in the core,
producing improved estimates on the core thermal structure. Secondly, we
match estimates for the present-day areotherm. Finally, we consider
recent experimental data for the core thermal conductivity,
kc, much lower than previously thought for Mars. In
order to yield a consistent dynamo cessation time we require
kc<18
Wm-1K-1. Furthermore, the majority
of our models indicate the core is fully conductive at present and too
hot to form any solid.