UNDERSTANDING VOLCANOES (BLOWING AND FLOWING) ON MARS: AN EVOLUTIONARY PROCESS

Our knowledge of Martian volcanic processes, and their spatial and temporal variations, is essential for a more complete understanding of volcanic processes on planetary bodies throughout the solar system, for constraints on the geologic evolution of Mars, and for the ability to identify the conditions under which and locations where Mars may have been able to support life.

We have compiled an up-to-date and easily digestible resource for students of Martian volcanology, whether they be undergraduate or graduate students, professionals, or interested laypeople. Years of examining the Mariner 9 and Viking Orbiter datasets provided an igneous paradigm in which effusive basaltic volcanism dominated Mars’ evolution, but with fascinating subtle differences in space and time. The community’s understanding of volcanological processes on Mars has evolved dramatically with the continued acquisition of data from a series of orbiters, landers, and rovers, and by studying Mars through the lens of steadily improving geologic mapping.

Our evaluation of the products of volcanism on Mars focusses on geographically distinct volcanic provinces across the planet, and the volcanological processes they represent. Effusion of relatively fluid lava has produced some of the largest volcanic constructs in the solar system, whereas other volcanoes have such shallow flank slopes that the edifice shape is only evident from orbit. Numerous small volcanic cones attest to widespread distribution of vents in areas such as eastern Tharsis and the Cerberus Fossae region. Process-related diversity across the planet is illustrated not only by a range of lava flow morphologies, but also by pyroclastic activity as expressed in the circum-Hellas region, the probability of volcano-ice interactions, and the still-unconfirmed hypothesis that the enormous Medusae Fossae Formation resulted from explosive eruptions. Evolution of the summit caldera complexes of Olympus Mons, Ascraeus Mons, and Alba Mons indicate complex magma chamber geometries and eruption-deflation sequences. The volcano-tectonic history of Syrtis Major Planum is unique, involving aspects of several other provinces along with features not seen elsewhere on the planet.

Like the rest of the Mars community, we eagerly await the delivery of additional data from both existing missions (such as Curiosity and InSight) and future explorations (by Perseverance, for example) of Mars to deepen our understanding of volcanologic processes on Mars.