Spectral evidence for magmatic differentiation within a martian plumbing system

Abstract Comprehensive studies of martian volcanic landforms offer otherwise inaccessible insights into subsurface magmatic systems that evolve and differentiate over time. Through orbital spectral analyses of a long-lived volcanic system south of Pavonis Mons that, over multiple eruptions, transitioned from a fissure vent to a point-source cone-forming vent, we identified mineralogical changes across morphologically distinct units. The fissure-fed lava flows exhibit olivine spectral characteristics, indicating deep-sourced magma, likely from the mantle or lower crust, while younger, finger-shaped lava flows on the cone are dominated by high-calcium pyroxenes, indicating a more evolved magma source. While these two different-aged units originate from the same regional plumbing system, their mineralogical differences suggest magmatic differentiation through crustal storage, possible assimilation, and fractional crystallization during subsequent cooling. These findings enhance our understanding of magma evolution in the late Amazonian on Mars.