Understanding what drives erosion (exhumation) in the tropical Northern Andes

Understanding how tectonic and climatic forces influence erosion and shape mountains is important to understand the evolution of the landscapes through earth’s history. This presentation aims to determine how do tectonic processes and climate variability interact to shape Earth’s tropical mountains.

This study focuses on the Eastern Cordillera of the Northern Andes, a mountain range located in Colombia in the tropics of South America. To obtain erosion/exhumation rates, I used thermochronology, which is a method that records—over timescales of millions of years—the rate at which rocks located at great depths within the Earth cool as they are transported to the surface through the erosion of overlying rock from the surface. The results show that the rates and timing of exhumation are spatially variable along the Eastern Cordillera and the highest erosion rates occur near the places that have the most tectonically active faults. These zones of highest exhumation are associated with inherited structures that are deformed preferentially.

Another major finding of this work is that higher precipitation rates are not always associated with higher erosion rates and, by extension, that precipitation rates along the Eastern Cordillera are not a major factor controlling erosion rates. Overall, this study underscores the importance of a thorough characterization of the location and recent activity of faults in a region to understand erosion patterns and natural hazards in tropical mountains.