Emeralds in the Eastern Cordillera of Colombia: Two tectonic settings for one mineralization

Colombian emeralds are formed through a hydrothermal-sedimentary process. O n the western side of the Eastern Cordillera, the deposits are linked by te ar faults and associated thrusts developed during a compressive tectonic ph ase that occurred at the time of the Eocene-Oligocene boundary, prior to th e major uplift of the Cordillera during the Andean phase (middle Miocene). On the eastern side of the Cordillera, emerald mineralization occurred earl ier, at the time of the Cretaceous-Tertiary boundary, during a thin-skinned extensional tectonic event linked to evaporite dissolution. This event pre dates the Andean phase, during which this part of the chain was folded and thrust over the Llanos foreland.