Implications of variable late Cenozoic surface uplift across the Peruvian central Andes

Area of Science:

• Geosciences
• Geodynamics
• Paleoclimatology

Background:

• Surface elevation changes are driven by geodynamic processes, influencing regional climate.
• Understanding the timing and mechanisms of Andean uplift is crucial for paleoclimate reconstructions.

Purpose of the Study:

• To determine late Cenozoic surface uplift in the Peruvian central Andes.
• To link surface uplift patterns to geodynamic processes and climate change.

Main Methods:

• Analysis of hydrogen isotopic compositions in hydrated volcanic glasses and modern stream waters.
• Utilizing water isotopes to reconstruct mean catchment elevations.
• Integrating isotopic data with paleoelevation estimates and geological information.

Main Results:

• Modern water isotopes accurately reflect catchment elevations (±500m precision).
• Isotopic data reveal rapid uplift (2-2.5 km) in the Western Cordillera and Altiplano (20-10 Ma), consistent with mantle foundering.
• Slower uplift (1.5-2 km) in the Eastern Cordillera (25-10 Ma) suggests crustal shortening.
• Ayacucho region reached modern elevation by ~22 Ma.

Conclusions:

• The timing of Andean orogeny correlates with the onset and intensification of coastal hyperaridity.
• Mantle lithosphere foundering and crustal shortening are key mechanisms driving Andean uplift.
• Reconstructed uplift patterns provide insights into the geodynamic evolution of the Andes and its climatic consequences.