Resumen de Caracterización mineralógica de la brecha fangosa de los volcanes de fango Anastasya y Almazán: talud medio del Golfo de Cádiz

Celia María Martín Puertas, María Pilar Mata Campo, Víctor Díaz del Río Español, Luis Somoza, L.M. Pinheiro

• This work shows the mineralogy of the mud breccia of two mud volcanoes of the Gulf of Cádiz: Anastasya and Almazán. The main minerals are: quartz, phyllosilicates and carbonates (calcite anddolomite). Feldspars and pyrite also occur as minor phases. Clay mineralogy of the <20 pm and <2 pm fraction is illite, chlorite, kaolinite and smectite. The clay mineralogy analysis shows that thesmectite content can be up to 29% of the total clay content. SEM study shows the texture and sizeof the main detrital components quartz, feldspars, calcite and phyllosilicates, but also shows authi-genic grains of framboidal pyrite and dolomite immersed in the mud breccia. Mineralogie analysis reflects that the mud breccia is made of a mixture of materials: the hemipelagic material of theslope; Miocene marls and clays that underlay the mud volcanoes and are discharged onto to the bottom surface, and diagenetic minerals possibly involved with the anaerobic oxidation of methanein the mud volcano.