Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Planets
Images of the surface of Mars all show a desert landscape with highly eroded rocks standing in a sea of sand. Massive rock outcrops typically display fossilized dunes and lake beds. Studying such sedimentary records is crucial for understanding the past climate and habitability of the red planet, which is why it has been the target of all Martian rover missions. However, Mars has also been a volcanic planet, and is host to the tallest and widest volcanoes in the solar system. Igneous rocks give insight into the interior structure and evolution of the planet, but they have until now been found only in our meteorite collections or as the occasional boulder strewn on a plain of sand.
This all changed when the Mars 2020 Perseverance Rover landed on the floor of the Jezero Crater. The mission targets mainly the prominent delta that spreads from a breach in the western wall of the crater. However, the landing took place a couple of kilometers away from the edge of the delta, in a much flatter and safer geological unit called the Máaz formation (named after the Navajo word for “Mars”). Perseverance spent more than a year studying this unit and the nearby Séítah formation (meaning “amidst the sand”) before heading to the delta proper.
Unlike what other rovers have found, the rocks of the Máaz formation show clear igneous texture and have not been transported long distances. They provide a unique opportunity to study Martian volcanic deposits where they were emplaced. Udry et al. [2022] document their geochemistry and morphology in detail. They show that the formation is likely a lava flow or perhaps a pyroclastic deposit emplaced on top of the Séítah formation. The rocks of the Máaz formation are all petrologically linked and differ from Martian magmatic rocks or meteorites. In particular, they are unrelated to the Séítah formation, even though it is also of igneous origin. The samples cached by the Perseverance Rover would therefore provide a unique view of the volcanic activity of Mars.
Citation: Udry, A., Ostwald, A., Sautter, V., Cousin, A., Beyssac, O., Forni, O., et al. (2022). A Mars 2020 Perseverance SuperCam Perspective on the Igneous Nature of the Máaz formation at Jezero crater and link with Séítah, Mars. Journal of Geophysical Research: Planets, 127, e2022JE007440. https://doi.org/10.1029/2022JE007440
—Laurent G. J. Montési, Editor in Chief, JGR: Planets