Carbonatos Metanógenos y Pirita Framboidal Autigénica: Geomarcadores de la Actividad de Organismos Quimiosintéticos en el Golfo de Cádiz

Résumé

The Gulf of Cadiz represents a special example for the study of the submarine processes of methane emission and oxidation. A great variety of seafloor structures were formed as consequence of these processes, highlighting the mud-volcanoes. Authigenic carbonates with different morphologies associated to mud-volcanoes were located and recovered, with special relevance of carbonate chimneys due to their abundance and features. In this work we present the review of the mineralogical, geochemical and textural studies of the different types of carbonates formed in the Gulf of Cadiz. Carbonate chimneys are the main candidates for their utilization as geomarkers of the environment and the processes that occur in the Gulf of Cadiz due, mainly, to their descriptive internal and external characters, and the presence of numerous internal clusters of pyrite and pseudomorph iron oxyhydroxides with framboidal morphology. Furthermore, the terrestrial environments where the methane is seeped and consumed could be considered as possible analogs to the needed active sources of methane in Mars and Titan that would assure their atmospherical renovation.