TY - JOUR A1 - Parra, Mauricio A1 - Mora, Andrés A1 - Jaramillo, Carlos A1 - Strecker, Manfred A1 - Sobel, Edward A1 - Quiroz, Luis A1 - Rueda, Milton A1 - Torres, Vladimir T1 - Orogenic wedge advance in the northern Andes : evidence from the Oligocene-Miocene sedimentary record of the Medina Basin, Eastern Cordillera, Colombia N2 - Foreland basin development in the Andes of central Colombia has been suggested to have started in the Late Cretaceous through tectonic loading of the Central Cordillera. Eastward migration of the Cenozoic orogenic front has also been inferred from the foreland basin record west of the Eastern Cordillera. However, farther east, limited data provided by foreland basin strata and the adjacent Eastern Cordillera complicate any correlation among mountain building, exhumation, and foreland basin sedimentation. In this study, we present new data from the Medina Basin in the eastern foothills of the Eastern Cordillera of Colombia. We report sedimentological data and palynological ages that link an eastward-thinning early Oligocene to early Miocene syntectonic wedge containing rapid facies changes with an episode of fast tectonic subsidence starting at ca. 31 Ma. This record may represent the first evidence of topographic loading generated by slip along the principal basement-bounding thrusts in the Eastern Cordillera to the southwest of the basin. Zircon fission-track ages and paleo-current analysis reveal the location of these thrust loads and illustrate a time lag between the sedimentary signal of topographic loading and the timing of exhumation (ca. 18 Ma). This lag may reflect the period between the onset of range uplift and significant removal of overburden. Vitrinite reflectance data document northward along-strike propagation of the deformation front and folding of the Oligocene syntectonic wedge. This deformation was coupled with a nonuniform incorporation of the basin into the wedge-top depozone. Thus, our data set constitutes unique evidence for the early growth and propagation of the deformation front in the Eastern Cordillera, which may also improve our understanding of spatiotemporal patterns of foreland evolution in other mountain belts. Y1 - 2009 UR - http://gsabulletin.gsapubs.org/ U6 - https://doi.org/10.1130/B26257.1 SN - 0016-7606 ER - TY - JOUR A1 - Mora, Andrés A1 - Gaona, Tatiana A1 - Kley, Jonas A1 - Montoya, Diana A1 - Parra, Mauricio A1 - Quiroz, Luis Ignacio A1 - Reyes, German A1 - Strecker, Manfred T1 - The role of inherited extensional fault segmentation and linkage in contractional orogenesis : a reconstruction of Lower Cretaceous inverted rift basins in the Eastern Cordillera of Colombia N2 - Lower Cretaceous early syn-rift facies along the eastern flank of the Eastern Cordillera of Colombia, their provenance, and structural context, reveal the complex interactions between Cretaceous extension, spatio-temporal trends in associated sedimentation, and subsequent inversion of the Cretaceous Guatiquia paleo-rift. South of 4 degrees 30'N lat, early syn-rift alluvial sequences in former extensional footwall areas were contemporaneous with fan- delta deposits in shallow marine environments in adjacent hanging-wall areas. In general, footwall erosion was more pronounced in the southern part of the paleorift. In contrast, early syn-rift sequences in former footwall areas in the northern rift sectors mainly comprise shallow marine supratidal sabkha to intertidal strata, whereas hanging-wall units display rapid transitions to open-sea shales. In comparison with the southern paleo-rift sector, fan-delta deposits in the north are scarce, and provenance suggests negligible footwall erosion. The southern graben segment had longer, and less numerous normal faults, whereas the northern graben segment was characterized by shorter, rectilinear faults. To the east, the graben system was bounded by major basin-margin faults with protracted activity and greater throw as compared with intrabasinal faults to the west. Intrabasinal structures grew through segment linkage and probably interacted kinematically with basin-margin faults. Basin-margin faults constitute a coherent fault system that was conditioned by pre-existing basement fabrics. Structural mapping, analysis of present-day topography, and balanced cross sections indicate that positive inversion of extensional structures was focused along basin-bounding faults, whereas intrabasinal faults remained unaffected and were passively transported by motion along the basin-bounding faults. Thus, zones of maximum subsidence in extension accommodated maximum elevation in contraction, and former topographic highs remained as elevated areas. This documents the role of basin-bounding faults as multiphased, long-lived features conditioned by basement discontinuities. Inversion of basin-bounding faults was more efficient in the southern than in the northern graben segment, possibly documenting the inheritance and pivotal role of fault-displacement gradients. Our observations highlight similarities between inversion features in orogenic belts and intra-plate basins, emphasizing the importance of the observed phenomena as predictive tools in the spatiotemporal analysis of inversion histories in orogens, as well as in hydrocarbon and mineral deposits exploration. Y1 - 2009 UR - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0950-091X U6 - https://doi.org/10.1111/j.1365-2117.2008.00367.x SN - 0950-091X ER -