In its southern part the Eastern Cordillera of Colombia (EC) displays a change in fold style which correlates with a change in slab configuration between the normal dipping southern Cauca and the flat dipping northern Bucaramanga segment and which may attest to a slab tear. South of this transition zone, the EC defines a compact antiformal structure, with its crest located close to its eastern mountain front. In its northern segment, the EC evolves into a composite belt with two mountain fronts separating an axial depression and marginal foreland thrusts contributing to a considerable widening. In this contribution we analyze the kinematic evolution of two representative cordilleran cross sections on either side of the transition zone by considering a geometric balancing and existing thermochronological data, in order to constrain their evolution. We then present results of analogue experiments which we performed in order to reproduce strongly mono- and bivergent thrust wedges and discuss their initial settings, which might give clues with respect to the rheological behavior of a relatively cold and a warm crust. Finally, we compare the observed deformational styles to surface expressions of known tear zones in order to conclude about common features and pending questions for future research.

  • Andreas Kammer, Camilo A. Conde Carvajal, Cristhian B. Riascos Rodríguez, Michael A. Avila Paez
  • akammer@unal.edu.co, dyayac@unal.edu.co, cbriascosr@unal.edu.co, miaavilapa@unal.edu.co