The role of impact and radiogenic heating in the early thermal evolution of Mars

TL;DR

This study models Mars's early thermal evolution, highlighting the significant roles of short-lived radionuclides and impact heating in causing planetary differentiation within the first 25 million years.

Contribution

It introduces comprehensive numerical simulations that incorporate both radiogenic and impact heating, offering new insights into Mars's early differentiation processes.

Findings

Short-lived nuclides like 26Al and 60Fe significantly contributed to early Mars heating.

Impact heating alone was insufficient for widespread melting and differentiation.

Mars likely experienced substantial differentiation within the first 1.5 million years of accretion.

Abstract

The planetary differentiation models of Mars are proposed that take into account core-mantle and core-mantle-crust differentiation. The numerical simulations are presented for the early thermal evolution of Mars spanning up to the initial 25 million years (Ma) of the early solar system, probably for the first time, by taking into account the radiogenic heating due to the short-lived nuclides, 26Al and 60Fe. The influence of impact heating during the accretion of Mars is also incorporated in the simulations. The early accretion of Mars would necessitate a substantial role played by the short-lived nuclides in its heating. 26Al along with impact heating could have provided sufficient thermal energy to the entire body to substantially melt and trigger planetary scale differentiation. This is contrary to the thermal models based exclusively on the impact heating that could not produce widespread melting and planetary differentiation. The early onset of the accretion of Mars perhaps within the initial ~1.5 Ma in the early solar system could have resulted in substantial differentiation of Mars provide it accreted over the timescale of ~1 Ma. This seems to be consistent with the chronological records of the Martian meteorites.