Influence of salt in the tectonic development of the frontal thrust belt of the eastern Cordillera (Guatiquía area, Colombian Andes)

摘要

Geological maps, seismic lines and data from a dry exploration well are used to develop a new structural model for a segment of the eastern foothills of the Eastern Cordillera of Colombia, emphasizing the role of salt tectonics. Milestones in the deformation history of the Guatiquía foothills are illustrated by sequential section restoration to selected steps. Uncommon structural geometries and sparse salt occurrences are interpreted in terms of a kinematic evolution in which Cretaceous salt migration in extension produced a diapiric salt wall, which was subsequently welded during the main episodes of the Andean compression, when the salt wall was squeezed generating a large overturned flap. Salt-weld strain hardening resulted in break-through thrusting across the overturned flap in late deformation stages. This research puts forward a pattern of salt tectonics previously unrecognized in the foothills thrust belt, which may be significant in other parts of the external Colombian Andes.