Emplacement of a passive-margin evaporitic allochthon in the Betic Cordillera of Spain

The Triassic section of the External domain of the Betic Cordillera is rootless and thus allochthonous. The frontal accretionary wedge of the Guadalquivir allochthon consists dominantly of Triassic evaporites and red beds forming a melange with Upper Cretaceous - Paleogene deep-water sedimentary rocks. Throughout the unit, Jurassic rocks are absent. It is here proposed that the widespread Triassic evaporites of the Guadalquivir allochthon were originally emplaced as gravitational allochthonous masses in a passive-margin setting much like the widespread allochthonous salt of the Texas-Louisiana Gulf of Mexico. Thus, on the Betic passive margin, allochthonous evaporites were first emplaced during the Late Cretaceous - Paleogene. Later, during Neogene time, these evaporites were overthrusted as an accretionary wedge to form the Guadalquivir allochthon. A schematic reconstructed position of the Guadalquivir allochthon places the original passive-margin allochthon in its continental-slope setting.