Scientists from the University of Houston have discovered that volcanism on Mars occurred over a period of at least two billion years, much longer than previously thought. Their findings are based on geochemical analyses of a Martian meteorite found in northwest Africa and have been published in Science Advances. The meteorite, a type of igneous rock known as shergottite, was found to have an age of approximately 2.4 billion years and is similar in composition and origin to a group of ten other Martian meteorites with ages of 327 to 574 million years. These rocks were likely ejected into space towards the Earth during a single impact 1.1 million years ago, which further suggests that they were all derived from the same volcanic source. Therefore, the spatial and temporal relationships of these meteorites indicate that volcanism must have occurred for over two billion years at the same location. This amazing discovery sheds new light on the formation of the planet and suggests that Mars was to some of the longest-lived volcanoes in the Solar System.
Journal reference: Lapen, T. J., Righter, M., Andreasen, R., Irving, A. J., Satkoski, A. M., Beard, B. L., Nishiizumi, K., Jull, A. J. T. & Caffee, M. W. (2017). Two billion years of magmatism recorded from a single Mars meteorite ejection site. Science Advances, 3(2).
Image: Olympus Mons, the largest volcano on Mars, as seen from the Viking 1 Orbiter. Credit: NASA.
Scientists at NASA have discovered evidence for flowing water on the surface of Mars. Spectral data recorded by the imaging spectrometer of the Mars Reconnaissance Orbiter indicates the presence of hydrated salts in recurring slope lineae at four different locations on the planet. These narrow streaks of low reflectance on the surface of Mars grow in the downslope direction during warm seasons when temperatures reach 250 K – 300 K and fade away during cold seasons. The hydrated salts most likely represent a mixture of magnesium perchlorate (Mg(ClO4)2.H2O), magnesium chlorate (Mg(ClO3)2.H2O) and sodium perchlorate (NaClO4.H2O), and appear to be most abundant when the recurring slope lineae are most extensive. This suggests that these structures are formed as a result of water flowing at the surface or in the shallow subsurface of Mars. The discovery of liquid water is a major step in the search for extant life on Mars.
Journal reference: Ojha, L., Wilhelm, M. B., Murchie, S. L., McEwen, A. S., Wray, J. J., Hanley, J., … & Chojnacki, M. (2015). Spectral evidence for hydrated salts in recurring slope lineae on Mars. Nature Geoscience.
Image: Recurring slope lineae in the Garni Crater on Mars as seen from the Mars Reconnaissance Orbiter. Source: NASA/Jet Propulsion Laboratory-Caltech/University of Arizona.
Mars is the second smallest planet in the Solar System and the fourth planet from the Sun. It has a mean radius of ~ 3390 km, a mean distance to the Sun of ~ 228 million km and an orbital period of ~ 687 Earth days. Mars is a terrestrial planet with a reddish color, which is related to dust and rocks at its surface that are enriched in iron oxides. The planet is surrounded by a thin atmosphere and is characterized by impact craters, volcanoes, valleys as well as polar ice. Mars is also known for Olympus Mons, the largest volcano in the Solar System, and Valles Marineris, one of the largest canyons in the Solar System.
Information source: NASA
Image: Mars and the Valles Marineris as seen from the Viking 1 Orbiter. Source: NASA/Jet Propulsion Laboratory-Caltech.