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indicate that Late Cretaceous initiation of transpressional deformation in this part of the northern Andes involved
small amounts of northwest-southeast contraction along the northeast-trending segments of faults. Although these
early faults did not breach the surface, they were probably rooted along a basal detachment along the lower part of
the Villeta Group where deformed fossils record high strain values. Continued deformation throughout Late
Cretaceous times generated a conspicuous deformation fabric that accommodated small amounts (less than 5%) of
internal deformation. Therefore, internal deformation can be ignored when performing two- and three-dimensional
modeling of this foldbelt (Montes et al., in press). Large scale Paleogene ENE transpressional deformation, although
spectacularly recorded by thick, folded molasse deposits and map-scale faults, is missing a mesoscopic deformation
fabric, probably due to strain hardening. Fabric elements associated with Late Cretaceous deformation were
passively rotated and translated along thrust sheets developed at this time. N...
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This document was uploaded on 02/06/2014.
- Winter '14