Secuencia de facies volcánicas en el área del río Odiel (Faja Pirítica Ibérica, España)

Abstract

We present a detailed study of a 10 km2 area located in the Odiel River, to the northwest of Zalamea la Real (northern flank of Riotinto antiform, Huelva), where we describe the main facies characteristics of a section of the Volcano-Sedimentary Complex (VSC) which is relevant to the stratigraphy of the central part of the Iberian Pyrite Belt (IPB). The following rock types have been distinguished: felsic and mafic sills, felsic volcaniclastics and siliciclastic rocks. Sills intrude at different parts of the stratigraphic column and show peperitic borders. Perlitic textures are very often found at the borders of large felsic sills. Volcaniclastic deposits consist of poorly organized individual packages, up to 20 m thick. All of the volcaniclastics exhibit a narrow range of exclusively juvenile volcanic clasts. We suggest that the studied volcaniclastic packages must have formed by mass-flow processes, directly related to volcanism, most probably related to the collapse of a zoned dome or, in some instances, to a pyroclastic mass flow entering seawater