An integrated morpho-stratigraphic approach has been used to reconstruct the Quaternary history of the Boiano basin, the largest tectonic depression of the Molise Apennine (Italy). Lacustrine, marshy and fluvial environments alternate all along the investigated infilling succession as a response to tectonic subsidence, volcaniclastic inputs and climate changes, from ca. 500 ka. Two tephra layers 40Ar/39Ar have been dated and referred to the Middle Pleistocene explosive activity of the Roccamonfina volcano, while a younger tephra layer has been related to the Campi Flegrei Neapolitan Yellow Tuff (ca. 15 ka). Pollen analysis has highlighted the vegetation changes related to the 100 ka glacial–interglacial cyclicity, between MIS 13 and 2. From 500 to 350 ka, a strong subsidence led to lacustrine deposition, while between 350 and 250 ka, a decrease in subsidence rates caused the transition to fluvial–marshy conditions and, at a later stage, to floodplain environments. The analysis of palaeosurfaces allowed the eomorphological evolution of the basin to be reconstructed since the Middle Pleistocene and the morpho-sedimentary events to be related to the SW-NE extensional tectonics affecting this sector of the central-southern Apennine. This tectonic behavior is also testified by the differential subsidence rates recorded within the basin through the analysis of two deep cores drilled in the center of the Boiano town

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The present study focuses on the morphotectonic evolution of the axial portion of the Southern Apennine chain between the lower Calore River valley and the northern Camposauro mountain front (Campania Region). A multidisciplinary approach was used, including geomorphological, field‐geology, stratigraphical, morphotectonic, structural, 40Ar/39Ar and tephrostratigraphical data. Results indicate that, from the Lower Pleistocene onwards, this sector of the chain was affected by extensional tectonics responsible for the onset of the sedimentation of Quaternary fluvial, alluvial fan and slope deposits. Fault systems are mainly composed of NW‐SE, NE–SW and W‐E trending strike‐slip and normal faults, associated to NW‐SE and NE–SW oriented extensions. Fault scarps, stratigraphical and structural data and morphotectonic indicators suggest that these faults affected the wide piedmont area of the northern Camposauro mountain front in the Lower Pleistocene–Upper Pleistocene time span. Faults affected both the oldest Quaternary slope deposits (Laiano Synthem, Lower Pleistocene) and the overlying alluvial fan system deposits constrained between the late Middle Pleistocene and the Holocene. The latter are geomorphologically and chrono‐stratigraphically grouped into four generations, I generation: late Middle Pleistocene–early Upper Pleistocene, with tephra layers 40Ar/39Ar dated to 158±6 and 113±7 ka; II generation: Upper Pleistocene, with tephra layers correlated with the Campanian Ignimbrite (39 ka) and with the slightly older Campi Flegrei activity (40Ar/39Ar age 48±7 ka); III generation: late Upper Pleistocene–Lower Holocene, with tephra layers correlated with the Neapolitan Yellow Tuff (~15 ka); IV generation: Holocene in age. The evolution of the first three generations was controlled by Middle Pleistocene extensional tectonics, while Holocene fans do not show evidence of tectonic activity. Nevertheless, considering the moderate to high magnitude historical seismicity of the study area, we cannot rule out that some of the recognized faults may still be active. Copyright © 2018 John Wiley & Sons, Ltd.

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. Le domaine d'Alboran dans l'évolution de la Méditerranée occidentale : la naissance d'un conceptMots-clés. -Orogène Bétique-Rif, Arc de Gibraltar, Apennins, Aperçu historique, Evolution géodynamique.Résumé. -Depuis le début des années 70 la majorité des reconstructions tectoniques de la Méditerranée occidentale dé-finissent le domaine d'Alboran comme un microcontinent ou une masse continentale principalement composée de roches paléozoïques et triasiques affectées par un métamorphisme « alpin » HP-BT. Durant près de trois décennies, depuis le milieu des années 80, le domaine d'Alboran était considéré comme un fragment de la chaîne alpine qui s'était dépla-cé vers l'ouest et était entré en collision avec l'Ibérie et l'Afrique du Nord pour former l'arc de Gibraltar et la chaîne bé-tique-Rif. En 2012, une hypothèse nouvelle a été présentée pour l'évolution de la Méditerranée occidentale, pour laquelle la chaîne bétique-Rif proviendrait du retrait d'une subduction des segments les plus occidentaux de la Tethys ligure plongeant initialement vers le SE sous la marge africaine. Cette interprétation considère les roches métamorphiques du « domaine d'Alboran » comme des séries crustales des marges continentales africaine et ibérique hyper-amincies et ayant subi un cycle complet de subduction-exhumation au-dessus d'une subduction en retrait en direction NW-W. Un résultat clef de cette hypothèse est que le domaine d'Alboran n'est pas un fragment de la chaîne alpine mais une consé-quence d'une dynamique de retrait. Dans cette contribution nous tentons d'élucider les raisons historiques derriè...

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