Estimating Primary Magmas From Mars With PRIMARSMELT: Implications for the Petrogenesis of Some Martian Rocks and the Thermal Evolution of Mars

• Published in: Journal of geophysical research. Planets 2024-11, Vol.129 (11), p.n/a
• Main Authors: Hernández‐Montenegro, Juan David, Asimow, Paul D., Herzberg, Claude T.
• Format: Article
• Language: English
• Subjects: Chemical composition; Crusts; Evolution; Geological history; Heat loss; Magma; mantle potential temperature; Mars; Mars surface; Martian basalts; Martian meteorites; Melting; Meteorites; Meteoritic composition; Meteors & meteorites; Olivine; Petrogenesis; Petrology; Planetary composition; Planetary evolution; Planetary interiors; Planetary mantles; Planets; Plate tectonics; Potential temperature; primary magmas; Rocks; Shergottites; SNC meteorites; Software; Subtraction; Tectonics; Terrestrial planets; Thermal evolution; Time measurement
• ISSN: 2169-9097; 2169-9100
• DOI: 10.1029/2024JE008508

Primary magmas form by partial melting in the mantle of a terrestrial planet and represent the starting material for building its crust. The compositions of primary magmas are critical for understanding the thermal history of planetary interiors, as they can be used to estimate mantle potential temperatures (TP) and track changes in the conditions of mantle partial melting over time. Here, we introduce PRIMARSMELT, a new member of the PRIMELT software family, calibrated to estimate the composition of Martian primary magmas and their formation conditions. We applied PRIMARSMELT to a comprehensive database of basaltic compositions from Mars. Our results are consistent with their petrology, requiring olivine addition to restore fractionated compositions to their primary parents and olivine subtraction from cumulate rocks. Individual primary magma solutions provide insights into the petrogenesis of specific Martian meteorites, with implications for the near‐primary nature of some primitive meteorites and the relationship between lithologies A and B in meteorite EETA 79001. Taken together, our results suggest nearly constant or potentially increasing mantle potential temperatures throughout the geological history of Mars. The average TP for young shergottite meteorites is ∼1,442 ± 40°C, similar to ambient mantle temperatures inferred from geophysical models. In contrast, older basaltic rocks record potential temperatures as low as ∼1,320 ± 48°C for igneous clasts in meteorites NWA 7034/7533. We suggest that, rather than plume‐related magmatism, shergottite meteorites record ambient mantle temperatures, with the thermal evolution trend possibly resulting from inefficient heat loss, as expected for a planet in stagnant‐lid mode. Plain Language Summary Primary magmas, formed from the melting of a planet's mantle, are the materials from which the crusts of terrestrial planets are formed. Establishing their composition helps us understand the thermal state of a planet's interior and how it changes over time. We developed PRIMARSMELT, a software tool that estimates primary magmas on Mars using the measured chemical compositions of Martian meteorites and surface rocks. When applied to different Martian samples, PRIMARSMELT produces results that shed light on their origins and relationships. Notably, when combining our results for some suitable samples with their ages, we found that the internal temperature of Mars appears to have remained steady or may even be increas