The SMU Geology Guest Speaker Series welcomes Dr. Catheryn Ryan

Catheryn Ryan PhD. Geology and Planetary Science Candidate University of Western Ontario

Catheryn Ryan is a PhD candidate at University of Western Ontario studying geology and planetary science. They received their BSc in geology at Saint Mary's University in 2016, where they conducted research on mapping a candidate Mars 2020 landing site. They continued to an MSc in earth and space science at York University, participating in the NASA BASALT Research Project and studying deep-UV laser-induced fluorescence spectroscopy techniques for determining the distribution of organic material in Mars-analogue basalts.

Catheryn's current interests lie in the geological characteristics of habitability on the early Earth and Mars, especially in volcanic environments. They have conducted field work in Idaho and participated in international field courses and Mars analogue missions. In their spare time, Catheryn enjoys rock climbing, sewing, hiking, knitting, photography, playing Dungeons and Dragons, and spending time with their dog, Ellie.

Title: "Tuff life; Distribution and Astrobiological Potential of Mars-relevant Terrestrial Hydrovolcanic Environments"

Abstract: Basaltic tuff at terrestrial hydrovolcanoes represents a habitable niche that was likely present on both the early Earth and Mars. Phreatomagmatic volcanism produces abundant glassy tuff which alters to palagonite with continued exposure to circulating aqueous fluids. Tuff glass from multiple terrestrial locations including tuff cones, tuff rings, maars, and sublagically-erupted tindars has been shown to contain microscopic textures indicative of microbial colonization. These putative biosignatures are hypothesized to form when lithotrophic microbes dissolve glass as they metabolize redox-sensitive elements.

My research has concentrated on two areas. Firstly, I have conducted studies of tuffs collected from Fort Rock Volcanic Field, Oregon and Western Snake River Plain Volcanic Field, Idaho, both of which are Pleistocene basaltic volcanic fields with structures that erupted into pluvial lake settings. This type of environment was common on Mars during the first billion years of its history. I have used XRD, EPMA, and petrography to document the morphology, distribution, and geological properties associated with putative biogenic alteration textures in glass. The goal of this research is to develop a set of exploration criteria for astrobiological sample selection on Mars, based on geological characteristics that are strongly correlated with the presence of these biosignatures in terrestrial samples.

Secondly, I have developed a global database of relevant volcanic environments on Earth with properties similar to Fort Rock, Snake River, and the few other locations where biogenic alteration textures have been documented. These volcanic fields are young, well-preserved, and have compositions and structures analogous to ones seen on Mars. This database is a tool for future investigations of habitability in Mars-relevant volcanic environments.