Caracterización y origen de la facies glauconítica de la cuenca del Guadalquivir

Abstract

Occurrences of glauconite in Tertiary materials of the Guadalquivir basin have been known nearly a century. Recent studies indicate that the glauconite is stratigraphically concentrated in two levels: the lower one (Miocene) being at the boundary between a detrital-carbonate formation and the «Blue Clays»; the higher one (Pliocene) at the transition between the «Blue Clays» and the Huelva Sand Formation. Different glauconitizacion degrees of organic remains have been observed in both glauconitic level studied. The environmental conditions during sedimentation of glauconite materials as deduced from palaeontological and sedimentological data, suppose that glauconite pellets may have formed in an open-sublitoral environment at around 50 m deep.