Constraints on the Cenozoic Deformation of the Northern Eastern Cordillera, Colombia

Abstract

The Eastern Cordillera of Colombia rose to maximum elevations of >5 km during the Cenozoic by inversion of a Mesozoic rift basin. Previous studies proposed that the exhumation of the Eastern Cordillera increased from ~6 Ma to the present due to the interplay between tectonic shortening and climate. In this study, we integrate new field observations, structural data, low‐temperature thermochronology, thermobarometry, and vitrinite reflectance along a section through the Tablazo, Cocuy, and Llanos regions to estimate the amount of shortening and the exhumation history. Our results indicate that shortening started as early as the latest Maastrichtian‐Paleocene in the Tablazo and Cocuy regions. Exhumation migrated eastward, starting in the Paleocene in the west and continuing in the Miocene in the east. The amount and rate of exhumation peaked in the Cocuy region with values of <5 km and < 0.4 km/Ma, respectively. At the highest elevations in the Cocuy Sierra, we also found evidence of a low‐pressure/high‐temperature metamorphic overprint, possibly related to shallow and local magmatic intrusions that occurred in the Late Miocene. Our cross‐section interpretation suggests a low amount of shortening (13%) that is mainly accommodated by high‐angle inverted faults and by the frontal thrust system. The presence of shallow magmatic bodies, moderate exhumation, and low shortening raises questions about the processes (isostatic versus dynamic) that drove the topographic growth of the high Cocuy Sierra.

Deep Crustal Faults, Shear Zones, and Magmatism in the Eastern Cordillera of Colombia: Growth of a Plateau From Teleseismic Receiver Function and Geochemical Mio‐Pliocene Volcanism Constraints

“…Therefore, we propose that the magmatic record of the EC, which is north of this latitude, is linked to the flat slab configuration that also triggers the Pliocene uplift and exhumation. This hypothesis agrees with recent findings of Siravo et al (), who gave evidence in the eastern flank of the EC for metamorphic overprints and signs of thermal perturbations in ZHe ages that are consistent with local magmatic intrusions in the late Miocene. In addition, modeling results presented by Siravo et al () suggest that slab shallowing and flattening between ~10 and ~6 Ma can explain the EC topography and can account for the fast exhumation in the Plio‐Pleistocene; they argue that if the asthenospheric wedge is hydrated enough, the slab flattening may be responsible for the topographic uplift of the EC.…”

Widening of the Andes: An interplay between subduction dynamics and crustal wedge tectonics

“…Indeed, the growth of the Eastern Cordillera initiated timidly in the Paleogene, i.e. before the flat-slab episode (Bayona et al, 2008;Horton et al, 2010;Siravo et al, 2018), but the main episode of uplift of the range is late Neogene, concomitant with the appearance of the horizontal subduction, as attested both by tectonic, thermochronological and paleobotanical data (Gregory-Wodzicki, 2000;Mora et al, 2015;Siravo et al, 2019).…”

Geothermal as resource for megacities

“…Barrera et al (2018) proposed that the lithospheric tear represents a mechanism for the emplacement of thermal anomalies related to late Miocene to Pliocene magmatic intrusions in the central sector of the Eastern Cordillera basin (Fig. 3b) (Siravo et al, 2018) numerous faults and fractures that control hot springs in the region (Gómez et al, 2015). The geothermal gradients of these anomalies reach locally 70 °C/km (Vargas et al, 2009) and could be linked to regional delamination processes and/or the ow of hydrothermal uids through the sedimentary sequence of the Eastern Cordillera basin (e.g.…”