Investigating Volcanic Environments on Mars and Earth using Radar

Abstract

Volcanic processes play a key role in the formation and evolution of terrestrial planets in the Solar System. On Earth, volcanism drives the recycling and growth of crustal material and is a major resurfacing mechanism. On other planets like Mars, volcanism reshaped almost 60 percent of its surface. This activity later waned, leaving behind a record of these changes in the subsurface stratigraphy. Orbital and in-situ radar remote sensing techniques can penetrate into these units and unpack the stratigraphy and geologic history of volcanic regions on Mars and Earth. The work contained in this dissertation utilizes orbital and ground-penetrating radar remote sensing techniques to map and interpret stratigraphy in what are primarily volcanic settings on Mars and Earth. An introduction to volcanism on Mars and Earth are included in Chapter 1, including an overview of radar remote sensing in planetary science. The discussion of Earth volcanism will specifically discuss Icelandic styles as Chapter 4 focuses solely on deposits associated with the Icelandic highlands volcano, Askja. Chapters 2 and 3 are investigations utilizing orbital and ground-penetrating radar, respectively, to map and characterize emplaced materials in two primarily volcanic environments on Mars. In Chapter 2, we map lava flows and other deposits near the volcano Ascraeus Mons in the Tharsis Volcanic Province. We also examine the radar characteristics of these deposits to determine the primary drivers of successful subsurface sounding are in these terrains. In Chapter 3, we utilize similar analysis techniques characterize and map the subsurface stratigraphy the floor of Jezero crater using the ground-penetrating radar payload on the Perseverance rover. We infer a volcanic origin for the crater floor units we examined and discuss the stratigraphy there as revealed from the radar data. Chapter 4 focuses on how radar can be used to satisfy in-situ resource utilization objectives and strategies for interpreting returns from the subsurface for human exploration in similar terrains on Mars or the Moon. Volcanic environments are a known challenge for radar due to surface and internal scattering resulting from their rugged textures. We apply techniques currently used to analyze radar remote-sensing data to noninvasively and unambiguously identify ice buried by volcanic tephra and discuss the implication for future in-situ resource utilization objectives for surface exploration of the Moon and one day, Mars. Chapter 5 summarizes all of our findings and discusses open questions and avenues for future work to address them.