A color mosaic of Olympus Mons, the largest volcano on Mars and in the solar system. Credit:  NASA/JPL-Caltech.

Volcanism is a prevalent geologic process on Mars, producing numerous landforms such as lava flow plains and shield volcanoes. The Tharsis volcanic region consists of three large shield volcanoes, including Olympus Mons, the largest volcano in our solar system. The volcanism of the Tharsis region was active relatively recently in Mars’ history, with some of the younger lava flows estimated to be only tens to hundreds of millions of years old. Understanding the eruption conditions of the volcanoes in the Tharsis region could provide information on the composition and structure of the interior of Mars, particularly in relatively recent times.

To understand these conditions, Sean Peters of Arizona State University and colleagues used high-resolution orbital data from the Mars Reconnaissance Orbiter, along with topographic data from Mars Global Surveyor and thermal imaging data from Mars Odyssey to map the morphologies of 40 lava flows in the Tharsis region in detail. The results of this research were compared to laboratory studies that investigated the relationship between eruption conditions and lava flow morphologies. The morphologies around Tharsis showed that despite Mars having thicker and wider lava flows than Earth, the lava flow rates and chemical compositions are within the same range as Earth. What makes the lava flows around Tharsis different from those on Earth is that they were erupting for a much longer period of time. The Tharsis volcanic province was likely active for billions of years, compared with millions of years for eruptions of large igneous provinces on Earth. Since the eruption of large igneous provinces has impacted Earth’s climate in the past, the eruption of the lava flows in the Tharsis region may have impacted the climate of Mars. READ MORE