Introduction: The Elysium volcanic province (EVP) is a location of great geologic interest on Mars. EVP is notable not only for the presence of three shield volcanoes, Elysium, Alber, and Hecates, but also for some of the most recent eruptions on the planet, with some interpretations suggesting activity even in the last few million years. Its predominantly Amazonian surface age and isolation in the northern hemisphere away from other volcano-tectonic regions make it an ideal locale to investigate igneous compositions during the most recent geologic period on Mars. Specifically, EVP experienced an extended period of volcanism; compared to large igneous provinces on Earth, the martian context has persisted orders of magnitude longer. Therefore, changes in mantle chemistry, pressure , and temperature are expected, as well as changes in fractional crystallization processes and crustal contamination. Due to the coarse length scale of the observation resolution and lack of resolved local features, these systems appear much simpler than their terrestrial counterpart. In addition, regional scale changes in eruptive processes of any given martian volcanic province over geologic time are still poorly understood. Related investigations are crucial for understanding how the martian crust and mantle have evolved in the absence of Earth-like plate-tectonics. Consequently, this project helps fill this knowledge gap by assessing the compositional evolution of Elysium as a major martian volcanic province, using remote sensing data sets (Mars Odyssey Gamma Ray and neutron Spectrometer suite (GRS), and gravity) and modeling (pet-rologic and thermoelastic). By analyzing data based on predictions from petro-logic modeling, we develop an expansive geologic history for the region that spans over 3 Ga. Our work shows a compositional transition in Elysium's volcan-ism coupled to differences in geologic age between NW and SE regions [1] (mapped Geology summarized in Fig. 1). The continuity of volcanic activity, and the notable spatiotemporal changes in the abundance of heat-producing radioactive elements (K and Th) along with others (Al, Ca, and Fe in particular) make this region an ideal case study for the evolution of volcan-ism on Mars [1,2]. Here we perform a detailed petro-logical and thermoelastic modeling to test the emerging hypothesis that compositional variability within EVP resulted from spatiotemporal changes in the depth of magma formation and present initial results.