Researchers examining late Miocene volcanic rocks from Colombia’s Northern Andes have identified evidence suggesting that major tectonic collisions between Central America and South America took place at an earlier point in geological history than scientists previously understood. The study, published in Earth and Planetary Physics, was conducted by Victor Piedrahita, J. Li, and an international team of geoscientists who focused on rock formations from the Combia Volcanic Province in central Colombia that formed roughly 12 to 6 million years ago during a critical period of interaction between the South American Plate and Central American continental crust.
The research team employed magnetic fabric analysis, a technique that examines the orientation of magnetic minerals within rock samples to determine whether internal structural features reflect original volcanic activity or resulted from later tectonic deformation. According to the findings, many of the volcanic rocks studied retained primary magnetic characteristics created by magma movement and volcanic processes, indicating they experienced minimal major tectonic deformation during the late Miocene period. While some locations showed evidence of deformation, these effects remained relatively limited in intensity and geographic distribution.
Based on their analysis, the researchers concluded that the most intense crustal compression and collision-related deformation in the Northern Andes had largely concluded before the late Miocene epoch. The evidence suggests that the strongest collisional events between Central and South America occurred during the Oligocene and middle Miocene periods, with tectonic activity becoming progressively weaker and more localized by the time the studied volcanic rocks were forming. The findings may contribute to improved geological models of Andes formation and enhance understanding of how plate interactions shaped the geological development of the Americas. The research received financial support from the National Natural Science Foundation of China.
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