Major: Geology and English Writing
Academic Affiliation: Boise State University
Growing up in the Southern Snake River Plain, the footprint of the Yellowstone supervolcano, Molly’s interest in volcanology was piqued by the presence of grandiose outcrops of volcanic deposits as close by as her backyard. As an undergraduate Geology and English Writing student at Boise State University, Molly spends her time studying local rocks with her family and her two rescued geo-dogs. This summer, Molly used remote sensing techniques to map and assess the rock-forming mineral olivine in the surface materials of the Terra Sirenum region on Mars. The presence of olivine provides an insight into the magmatic and geomorphologic processes that have created the Martian surface we see today. Thus, this project contributes to the overall conceptual understanding of the surficial workings of the Southern Highlands as they relate to the geologic history of planet Mars.
Using remote sensing techniques to assess the geologic context of olivine-bearing materials within Terra Sirenum, Mars
Understanding olivine-bearing materials in Terra Sirenum provides insight into the magmatic and hydrologic processes that shaped the Southern Highlands of Mars. Our study addresses two questions: What is the geologic context of olivine compositions in the study area in Terra Sirenum? And what does olivine abundance, composition, and geologic context suggest about the magmatic and weathering processes in Terra Sirenum? To answer these questions, we mapped an area with low dust coverage in Terra Sirenum using JMARS (Gorelick et al., 2003). We used Thermal Emission Imaging System (THEMIS) data to map the extent of olivine deposits in the study area (i.e., daytime decorrelation stretched images) as well as to understand their degree of consolidation (i.e., global thermal inertia map of Edwards et al. 2011, which used nighttime images). To investigate the specific olivine composition, we used the Thermal Emission Spectrometer (TES) global maps of Forsterite/Fayalite compositions from Koeppen and Hamilton (2008). We found that the olivine compositions vary from most iron-rich types (Fo01) to the most magnesium-rich (Fo91), with the vast majority of those deposits with TES coverage as Fo68. The results of our study are consistent with those implied by the magma overturn model of Elkins-Tanton (2003), which explains the compositional changes in Martian magmas over time. In addition, the extent of olivine-bearing deposits within our study area suggests that mechanical weathering (e.g., aeolian and gravity-driven processes) is more likely to dominate the sedimentary record in recent geologic time over water-driven processes. Our results add to the current state of knowledge by detailing the present-day surface geology of our study area in Terra Sirenum. Our results have implications for Martian magma evolution as well as the extent water has played in shaping the surface of the planet.