Gavin Tolometti is studying ancient lava flows in Idaho, USA, to compare them with lava fields on the Moon and Mars
For decades, planetary scientists have explored our solar system to understand the processes involved in planetary formation. To achieve this, the scientists have studied volcanism in our solar system, focusing on volcanic lava fields observed on other rocky planets and moons. In my graduate research, I am studying the surface and compositional properties of lava flows located at Craters of the Moon National Monument and Preserve (COTM) in Idaho, the largest ‘fresh’ lava field in the contiguous United States. The goal of my research is to understand how this lava field formed and compare it to similar lava fields observed on planetary bodies. We study the lava flows on other planets by analysing their morphology and surface roughness. Surface roughness is a measure of how smooth a lava flow is, ranging from smooth, rubbly, and blocky. The surface roughness of lava flows is inferred using radar remote sensing, which is achieved using specialized instruments on satellites. However, radar remote sensing has its limitations. It cannot analyse the mineralogy of the lava flows (i.e., what they are made of), which is essential for understanding the processes involved in their formation. To overcome these limitations, I selected a lava field on Earth to use as a planetary field analogue site. Analogue sites are locations on Earth that can be compared to locations on other bodies in our solar system. I selected COTM because it hosts many different lava flows with a wide range of surface roughness.
My focus is on establishing a relationship between the surface roughness, geochemistry, and petrography (mineralogy and crystalline textures of the lava) of six different lava flows in COTM. Geochemistry and petrography provide information about the lava flows’ resistance to flow and its temperature, both vital factors that control their surface roughness. The NASA FINESSE (Field Investigations to Enable Solar System Science and Exploration) team have used COTM as a field site for studying planetary volcanism because it shows remarkable resemblances to locations on the Moon and Mars. By establishing a relationship between the surface roughness, geochemistry, and petrography of COTM lava flows, comparisons can be made to locations on the Moon and Mars exhibiting similar surface roughness features. COTM lava flows with surface roughness comparable to other lava flows in our solar system can be inferred to have similar compositions. We can then interpret those lava flows developed the same way, which provides a better idea of the processes occurring within the planet’s interior. This will build on our understanding on how Earth, and other rocky planets and moons formed and evolved in our solar system.