WHAT COULD BE LEARNED ABOUT THE GEOCHRONOLOGY OF MARS FROM SAMPLES COLLECTED BY M-2020.

Abstract

Based on meteoritic evidence, Mars accreted as early as 2 Ma after the formation of the first solids in the solar system [1] from material with an OTi-Cr-Ni isotopic provenance distinct from the EarthMoon system [2]. It likely formed a magma ocean within ~100 Ma after solar system formation [3], from which the martian core last equilibrated with its mantle at pressures of ~14 GPa [4]. The formation of most of the mass of the Martian crust is constrained to have occurred by 4.35 Ga [5,6]. Remanent magnetization in martian meteorite ALH 84001 demonstrates a dynamo had initiated on Mars at or before 4.1 Ga [7]. Sample return is necessary because meteorites lack geologic context and their orientation with respect to the paleomagnetic field is not known [8].