The Alboran domain in the western Mediterranean evolution: the birth of a concept

Abstract

Since the early 70’s the majority of tectonic reconstructions of the western Mediterranean employ the Alboran domain notion as a migrating microcontinent or landmass mainly composed of Paleozoic-Triassic rocks affected by ‘Alpine’ HP-LT metamorphism. For nearly three decades, since the mid-80’s, the Alboran domain was considered as a fragment of the Alpine chain that moved westward, colliding into Iberia and North Africa to produce the Gibraltar arc and Betic-Rif chain. In 2012, a new hypothesis for the evolution of the western Mediterranean was presented in which the Betic-Rif orogenic chain originates from rollback of an initially SE-dipping subduction of the westernmost segments of the Ligurian-Tethys under the Africa margin. This interpretation considers the metamorphic ‘Alboran domain’ rocks as crustal successions of the hyper-extended African and Iberian continental margins, which have undergone a complete subduction-exhumation cycle above a NW- to W-retreating subduction. A key outcome of this hypothesis is that the Alboran domain is not a fragment of the Alpine chain but a consequence of rollback dynamics. In this contribution we try to elucidate the historical reasons behind the classical ‘Alpine’ interpretation of the Betic-Rif, by briefly describing key contributions, which appear linked in a logical sequence that traces the evolution of the Alboran domain concept since its original formulation by Andrieux and coauthors in 1971.