Resumen de Mineralogía y textura de carbonatos microbianos ligados a emanaciones de metano en el Golfo de Cádiz: datos comparativos de Fila de Hormigas, Cornide, Hespérides e Ibérico
María Pilar Mata Campo, Concepción Taberner Hernández, Luis Somoza, Víctor Díaz del Río Español, F. Pérez Outeiral, Celia María Martín Puertas
Data collected during several cruises in the Gulf of Cádiz revealed an intense area of emissions of hydrocarbon-enriched fluids related to the ongoing movement and development of diapirism of the allochthonous units. Vast fields of hydrocarbon-derived carbonate chimneys at depths between 500and 1200 m were reported. Chimneys and crusts collected showed a wide range of morphologicaltypes and are made of authigenic carbonates including detrital grains. In this study samples from Fila de Hormigas, Cornide, Hespérides and Ibérico sites, were studied in order to characterize and compare them with previous results of Ibérico site. Carbonate mineralogy show differences between the studied sites being dolomite more abundant in Cornide and Ibérico while calcite andhigh-Mg calcite are more abundant in Fila de Hormigas and Hespérides sites. Petrographic data donot show significant differences between the samples of the studied sites being the most commonfeature a texture of fossiliferous micrite and dolomicrites with silty detrital grains. Pyrite has beenalso observed as framboids or irregular aggregates. Although the authigenic carbonates and sulphides are related to microbial processes, diagenetic processes should be considered in the genesis of dolomite in these samples.
