Ancient Andean Landscape Reconstructed From Volcanic Deposits
Researchers mapped a terrain buried 21.9 million years ago, indicating slow and steady mountain uplift.
Updated on Sept. 21, 2026 in Geology
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Geologists reconstructed an ancient landscape in northern Chile buried by the massive Lauca Caldera eruption 21.9 million years ago. The study, published on September 11, 2026, utilized erosion simulations to analyze the terrain beneath the volcanic debris.
Why it matters
This research resolves a long-standing debate over whether the Andes rose through recent, rapid pulses or a prolonged, consistent process. The findings confirm a slow uplift rate, favoring the hypothesis of a steady growth phase spanning 40 to 50 million years.
The study measured an uplift rate of 0.26 kilometers per million years, which is equivalent to approximately 2.5 centimeters per century. The volcanic deposit created by the Lauca Caldera spans an area six times larger than Santiago and reaches a maximum thickness of one kilometer.
The players
Science Advances
A peer-reviewed, open-access journal published by the American Association for the Advancement of Science covering foundational research.
The details
Researchers simulated ancient river erosion patterns to map the topography concealed beneath the thick blanket of volcanic rock. By applying these models to the shape of the deposit, the team identified which terrain configurations could have existed before the eruption, noting that only landscapes with relatively low relief fit beneath the current volcanic structure.
Timeline
21.9 million years ago: The Lauca Caldera erupted in northern Chile.
September 11, 2026: The study was published in Science Advances.
The Tech Race
This finding marks a departure from theories of rapid, recent mountain building that have previously dominated models of Andean tectonic evolution. It shifts the field toward the evidence-based consensus that the Andes rose slowly and steadily over 40 to 50 million years.
The simulation methodology established in this study provides a new tool for geologists to reconstruct lost topographies globally. Future applications could allow researchers to apply these erosion models to other volcanic sites worldwide to better understand tectonic development.
The takeaway
The study confirms that the Andes underwent a steady, gradual rise rather than a series of abrupt geological events. Interested researchers should monitor how this erosion-model-based reconstruction technique is applied to other volcanic provinces in upcoming tectonic papers.
Further reading
For more on how modern modeling techniques clarify the history of our planet, visit the Geology section.
More information
Read the complete Science Advances research publication to see the full erosion modeling data.
Source note: This article includes information reported by SciTechDaily.
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