Thermochronology is widely used to track the exhumation of rock towards the Earth’s surface. Over the last decade, the amount of thermochronological data available for the Northern Andes in Colombia has increased considerably. Because of this, the thermal history of many parts of the Northern Andes is fairly well known. This knowledge helps us identifying different exhumation pulses of the mountain belt, especially the last orogenic episode (Pleistocene) has been identified in several places of the Eastern Cordillera, the Santander Massif, and the Llanos foothills. However, besides the large thermochronological dataset north of latitude 4°N, the data are less abundant to the South, and the cooling history of the Northern Andes remains unclear in that part of Colombia.
This contribution presents new evidence of the last Andean orogenic pulse recorded in the Northern Andes towards the southern junction of the three Colombian Cordilleras (1°N). Data agrees with the NE-SW trend of young ages over the Eastern foothills of Eastern Cordillera. The new Apatite fission-track (AFT) data of bedrock and modern river sediments show a Pleistocene signal of about 1.8 to 2.6 Ma, with high exhumation rates of about 1 km/Myr, assuming a thermal gradient of 30°C/km. Furthermore, an exhumed AFT partial annealing zone is detected in an elevation profile around 1700 m.a.s.l, which also reflected in the youngest detrital age peaks of the Sangoyaco creek, near Mocoa town.
Recent studies over Eastern cordillera propose a tectonic exhumation control rather than climate one. The presence of an exhumed AFT Partial annealing zone and young detrital AFT data support the idea that exhumation was driven by tectonics, possibly related to the Nazca plate movement and controlled by the morphology of Eastern Cordillera.
- Villamizar-Escalante, Nicolas (*) ¬; Bernet, Matthias (**); Amaya, Sergio (*); Peña-Urueña, Mary (*); Zuluaga, Carlos (***); López-Isaza, Julián (*); López-Isaza, Sergio (****)
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