As on Earth, So on Mars: Magmatic Records of Planetary Evolution

Magmatic processes play a central role in the thermal, chemical, and hydrologic evolution of rocky planets by linking deep planetary interiors to their crusts and surface environments. This thesis integrates igneous and metamorphic petrology, stable isotope geochemistry, and thermodynamic modeling to investigate how magmatic rocks record the coupled evolution of planetary interiors and surface environments on both Earth and Mars. On Earth, I focus on sediment-derived magmas—strongly peraluminous granites (SPGs) and associated pelitic migmatites—which form by partial melting of metasedimentary crust and preserve geochemical signatures inherited from surface-processed materials. On Mars, I focus on primary and weakly evolved mafic magmas, which provide direct constraints on mantle temperatures, crustal differentiation, and the role of magmatism in sustaining subsurface water. The first part of the thesis examines how sedimentary signatures are transferred into granitic magmas during crustal anatexis and what these signatures reveal about Earth’s long-term surface evolution. Iron isotope measurements and petrological modeling of the Neoarchean Ghost Lake Batholith show that partial melting largely homogenizes extreme sedimentary isotopic heterogeneity while preserving a resolvable record of bulk source composition, establishing SPGs as robust archives of secular iron isotope evolution in siliciclastic sediments. Building on this framework, triple-oxygen-isotope analyses of garnet in sediment-derived granites and migmatites are used to reconstruct weathering temperatures and meteoric water compositions from the Neoarchean to the Mesozoic, revealing discrete climate regimes linked to atmospheric oxidation, glaciation, and supercontinent cycles and demonstrating that sediment-derived magmas provide a lithology-integrated archive of Earth’s surface environments. The second part of the thesis addresses how Martian magmatism records the thermal evolution of a stagnant-lid planet and its interaction with the hydrosphere. I introduce PRIMARSMELT, a new petrological modeling tool for reconstructing primary magma compositions and mantle potential temperatures from Martian meteorite and rover data. Application of this approach indicates that Martian mantle temperatures have remained nearly constant—or may have increased—through time, consistent with inefficient heat loss in the absence of plate tectonics. I further show that, although Martian magmas inevitably generate water-rich fluids during differentiation, fluid–rock reactions rapidly seal permeability, implying that any present-day liquid water in the Martian crust must be continuously supplied by active magmatic degassing. Finally, mineral-scale observations from the Perseverance rover in Jezero crater demonstrate that ultramafic cumulates of the Séítah formation and basaltic lavas of the Máaz formation formed within the same magmatic system, linking intrusive and extrusive processes and illustrating how crystal accumulation and differentiation generate lithologic diversity in the Martian crust. Together, these studies show how magmatic processes record the thermal evolution of planetary interiors and mediate their interactions with crustal and hydrologic systems, providing a comparative framework for understanding how rocky planets build crusts, cycle volatiles, and evolve toward—or away from—habitability.