Publicación:

Gorgona Island (Colombia) as a terrestrial analog of Syrtis Major (Mars): Evidence from geochemical meta-analyses and compositional figures of merit

Resumen

The identification of terrestrial analogs is a key strategy for advancing our understanding of the geological and geochemical evolution of Mars. This study evaluates the potential of Gorgona Island (Colombian Pacific) as a geochemical analog of Syrtis Major. Gorgona Island hosts a diversity of mafic and ultramafic lithologies, including basalts, gabbros, picrites, dunites, wehrlites, and also komatiites, which are the youngest reported on Earth. To assess the degree of compositional similarity, a meta-analysis of previously published data was conducted, comparing geochemical information from Gorgona Island with that derived from orbital instruments on Mars (TES, GRS, OMEGA, and CRISM) and from SNC meteorites. The analysis focused on classical discriminant ratios (Al₂O₃/TiO₂) and Compositional Figures of Merit (FOMc), applied both to individual datasets and to averaged values weighted by the areal proportion of lithologies on Gorgona Island. The results show that enriched and depleted basalts, along with Spinifex-Textured komatiites (containing <18% MgO), exhibit a high degree of geochemical similarity with Syrtis Major (FOMc >0.87), whereas dunites and wehrlites consistently display low values. The positive slope of the Al₂O₃/TiO₂ ratio observed in both Gorgona and Mars is characteristic of MORB-type oceanic crust, reinforcing the link between Terrestrial MORB/OIB and Martian Basalts described by previous studies. These findings highlight Gorgona Island as a robust terrestrial analog of Syrtis Major, providing a natural laboratory for investigating magmatic processes relevant to Mars. Furthermore, this work outlines future directions, including the acquisition of new high-resolution geochemical data from Gorgona Island and the integration of recent in situ data from Mars, with the aim of refining comparative models of planetary magmatism.