Geomorphic and exhumational response of the Central American Volcanic Arc to Cocos Ridge subduction

A new study reveals that the geomorphic and exhumational evolution of the Talamanca Range-La Amistad Reserves, part of the extinct Central American Volcanic Arc, is intricately linked to the subduction of the Cocos Ridge. Researchers identified a relict erosional landscape at high elevations, characterized by low relief and shallow plutonic rocks, which provides critical insights into the range's cooling and erosional history from the late Miocene to present. Analysis of river longitudinal profiles and knickzones suggests that rock uplift during the growth of the Cordillera de Talamanca was no greater than approximately 2 kilometers. Low-temperature thermochronometry data, including apatite (U-Th)/He and fission track analyses on Mt. Chirripó, indicate that rapid cooling in the late Miocene was due to secular cooling rather than exhumation. The study concludes that significant geomorphic features such as rapid incision and differential rock uplift are relatively young, associated with the onset of Cocos Ridge subduction less than 3 million years ago. This finding separates the cessation of arc volcanism in the late Miocene from the initiation of ridge collision, reflecting recent changes in the plate boundary system.

Van Soest, M., Morell, K.D., Fisher, D.M., & Kirby, E. (2012). Geomorphic and exhumational response of the Central American Volcanic Arc to Cocos Ridge subduction. Blackwell Publishing Ltd. https://doi.org/10.17615/61K5-KG12