Recess drawn by the internal zone outer boundary and oblique structures in the paleomargin-derived units (Subbetic Domain, central Betics): An analogue modelling approach

The Subbetic Domain, comprising the South Iberian paleomargin-derived units, is a fold-and-thrust belt developed over a ductile substrate showing a complex structural pattern. In the central Betics, a main trend can be defined, with respect to which frequent oblique structures are observed. These oblique structures, often subperpendicular to the main trend, are not located along transfer zones but rather are present everywhere in the fold-and-thrust belt. Moreover, they are coetaneous with those drawing the main trend. This complex pattern is situated in front of a recess marked by the outer boundary of the internal zones – the Alboran Domain – which acted as backstop. Analogue models were designed to study the influence of such a recess on a ductile-brittle multilayer. One of the models, in which the backstop recess is symmetric with respect to its direction of movement, shows a high variation in the orientation of the resulting structures, being not only qualitatively but also quantitatively similar to the studied natural case.