115-8 Spectral Signatures of Water-Lava Interaction at Mud Lake, Idaho: Defining End-Members for Mars Analog Studies

Session: Petrology, Volcanology, and Mantle Plumes across the Solar System (Posters)

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Volcanic terrains formed through interactions between lava and surface or shallow groundwater produce diverse eruption styles and alteration features. While Martian hydrovolcanic studies have largely focused on high-water scenarios, such as tuff cones or palagonitized deposits, low- to moderate-water interactions are comparatively understudied. This work investigates a rare terrestrial example of such interactions at Mud Lake, Idaho, located on the northeastern margin of the Eastern Snake River Plain (ESRP). The site features welded and non-welded spatter deposits, sintered scoria, and lacustrine clasts within the spatter, interpreted as evidence of a periodic low- to moderate-water lava interaction system, making it a valuable Mars analog. 

The objective of this study is to define diagnostic spectral end-members for representative lithologies at Mud Lake, assess their relationship to mineralogy and textures, and evaluate their utility for rover-based exploration. We collected in-situ visible/near-infrared (VNIR) spectra using the TerraSpec Halo field spectrometer, targeting five lithologic groups found at Mud Lake: red spatter, grey welded spatter, sintered scoria, lacustrine clasts, and lithic blocks. These data were paired with petrographic observations, SEM/EDS imaging, and XRD for clay mineral confirmation to characterize textures and alteration features. 

Preliminary results reveal distinct spectral absorption patterns linked to mineral phases, oxidation state, and degree of alteration for each rock group. These signatures, when interpreted alongside morphological and mineralogical context, offer a framework for detecting low-water, less explosive lava-water interactions that are often challenging to distinguish in rover or orbital datasets. 

By establishing spectral end-members from a field site with relatively known eruptive and hydrologic history, this study provides a reference framework for identifying similar features on Mars. Our findings suggest that even periodic, low-intensity lava-water interactions can leave behind diagnostic spectral signatures, providing a valuable tool for identifying subtle or transient alteration features that might otherwise be missed in planetary datasets. These results are especially relevant for missions seeking to identify past aqueous activity and potential habitable environments in volcanic regions on Mars. 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8617

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