Facies architecture, emplacement mechanisms and eruption style of the submarine andesite El Barronal complex, Cabo de Gata, SE Spain

Abstract

El Barronal complex consists of a succession of andesite lavas and andesite volcaniclastic facies interbeddedwith carbonate and siliciclastic sedimentary rocks. Carbonate and siliciclastic rocks were deposited in a shallow- marine environment during periods of volcanic quiescence. Lavas consist of an inner coherent core grading out- ward into hyaloclastite brecciamade of dense clasts that in turn grade into hyaloclastite brecciamade of vesicular clasts, in massive to layered zones. Volcaniclastic facies contain clasts produced during explosive eruptions and reworked clasts from sources above wave base. Volcaniclastic facies were deposited from cold granular flows with different grain size populations. Stratigraphy and facies architecture at El Barronal suggest that a succession of several discrete eruptive events occurred with a similar cyclic pattern made of an initial explosive phase followed by effusive emplacement of lavas, in turn followed by a period of quiescence of volcanic activity. Hyaloclastic fragmentation of magma took place in the final stages of lava emplacement, allowing only for local disorganization of the jigsaw-fit texture.