Liu, and 70 co-authors reported mid-2022 that the Perseverance rover landed in Jezero crater on Mars in February 2021. Farley et al.(below) describe the geologic units investigated by the rover as it began to traverse the crater floor, based on images and spectroscopy. The authors found that the rocks are of igneous origin, later modified by reactions with liquid water. They also described the collection of drilled samples for potential return to Earth by another spacecraft. Liu et al. present compositional data here for these igneous rocks based on x-ray fluorescence measurements. They found similarities with some Martian meteorites and conclude that the igneous rocks formed from crystals that sank in a thick sheet of magma. Together, these studies constrain the history of Jezero crater and provide geological context for analysis of the drill samples.
The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. The authors investigated the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, they performed a petrographic analysis of the Bastide and Brac outcrops within this unit. They found that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarse-grained olivine, similar to some Martian meteorites. They interpreted them as an olivine cumulate, formed by settling and enrichment of olivine through multistage cooling of a thick magma body.
RELATED RESEARCH ARTICLES:
- Compositionally and density stratified igneous terrain in Jezero crater, Mars
BY ROGER C. WIENS, ARYA UDRY, OLIVIER BEYSSAC, ET AL. - Ground penetrating radar observations of subsurface structures in the floor of Jezero crater, Mars
BY SVEIN-ERIK HAMRAN, DAVID A. PAIGE, ABIGAIL ALLWOOD, ET AL. - Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars
BY K. A. FARLEY, K. M. STACK, D. L. SHUSTER, ET AL.
[The original working URL: https://www.science.org/doi/10.1126/science.abo2756 ]
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