The Romeral shear zone marks the geological boundary between the physiographic Central and Western cordilleras of the Colombian Andes. It demarcates and encompasses the main locus of deformation associated with the amalgamation and geological-structural evolution of the Northern Andean region during the Meso-Cenozoic, although as an ancient plate boundary, its origins may be traced into the Late Paleozoic. Today, Romeral corresponds to a km-scale shear zone containing poly-deformed, structurally juxtaposed fragments and slivers of a wide range of rock types, of varying ages and diverse origins, including metaigneous and metasedimentary blocks of the disjointed and reworked paleo-autochthon, fragments of pericratonic and possibly exotic oceanic margin, and late, autochthonous siliciclastic and volcanic sequences, each reflecting distinct development stages in the complex plate dynamics of the Northern Andean paleo-margin.