Grant: Discovery Grants Program - Individual

My research includes participation in planetary rover missions (Mars Science Laboratory, MSL, Participating Scientist, PS, 2012-2022, Collaborator 2022-present and Mars 2020, M2020, PS 2020-present) and analog Earth-based field and lab studies at volcanic fields. My long-term objectives are to differentiate the contributions of magmatic, aqueous alteration, and sedimentary processes to the history of volcanic and volcaniclastic rocks at rover landing sites and at volcanic fields on Earth in order to understand the evolution of Mars and other planets. My short-term objectives respond to discoveries encountered by rover missions: (1) Mars rover studies to understand the relative contributions of magmatic processes, aqueous alteration, and surface dust to rock histories. I will use chemical and microscopic imaging data to: a) determine of the effect of dust on rock analyses by estimating percentage areal dust coverages using microscopic imaging and comparing with compositions [J16]; b) identify the nature and composition of crystalline materials seen by the rovers; and c) identify elemental variations and micro-textures that may be linked to secondary alteration processes and conditions (water:rock ratios, temperature, pH, and fO2) and that may be critical for determining habitability for microbial life. (2) Constraining the conditions and relative timing of biotic and abiotic alteration at continental volcanic fields. Mafic volcanic fields that erupted in ancient lake environments contain diverse volcanic landforms, textures and mineral assemblages that reflect varying water levels and volcanic and alteration processes and conditions. Micro-textural biosignatures (micro-tubule and granular textures), thought to form by microbial processes, termed putative biogenic alteration (PBA), have been identified in glassy hydrovolcanic tuff at these settings in association with low temperature hydrothermal minerals [J27]. My goals are: a) to characterize the volcanic, alteration, and environmental histories of hydrovolcanoes with hydrothermally altered tuff where PBA likely occurs; b) to identify and describe any PBA to determine if they formed by biological processes; c) to test the hypothesis that the relative timing of PBA and abiotic alteration and fluid chemistry can be constrained by alteration mineralogy and rock textures; and d) to constrain the best set geologic characteristics to predict PBA occurrence using rover analog techniques. (3) Earth-based field and laboratory studies to characterize igneous and alteration mineral assemblages and geochemical variations of alkali basaltic rocks with Mars-relevant analytical techniques and scales. Bulk chemical tracers for igneous and alteration processes include minor and trace elements measurable by planetary instruments (K, P, Ti, Mn). One goal will be to investigate how various bulk chemical changes due to aqueous alteration is reflected in micro-elemental variations and rock textures.