The geological history of a Martian volcano

Abstract

The nakhlite meteorites are igneous rocks from Mars (Treiman 2005). The nakhlites sample a single volcanic edifice that erupted several times between 1.4-1.3 Ga (Cohen et al., 2017). They have also been affected by hydrothermal activity on Mars ~630 Ma (Borg & Drake 2005) and were ejected from Mars in a single impact event at ~11 Ma (Treiman 2005). Therefore, the nakhlite meteorites are a key sample suite for understanding volcanic activity, habitability and impact processes on Mars. A key challenge in making inferences regarding the red planet from the study of Martian meteorites is that the samples that we have on Earth lack their geological context – we do not know from where on the Martian surface they originated. Advanced machine learning crater counting algorithms are being developed to identify candidate craters (Benedix et al., 2020) while the Mars Sample Return campaign has been initiated to bring samples to Earth from known localities on Mars. Additionally, by applying new quantitative petrographic techniques it is possible to reconstruct the formation and geological history of the meteorites we already have such as the Martian nakhlite igneous rocks. Here we applied correlative microscopy including electron backscatter diffraction, transmission electron microscopy and atom probe tomography alongside numerical simulations to Martian nakhlite meteorites to provide new insights into their geological history, including: 1) evidence of multiple igneous emplacement mechanisms (Daly et al., 2019a); 2) providing tight constraints on the geomorphology of the launch site on Mars (Daly et al., 2019b); 3) outline a analytical pipeline to maximize the science obtained by Mars Sample Return (Daly et al., 2020).