A breakthrough study published in the Archaeological Science Review has utilized a novel Chlorine-36 surface exposure dating methodology to provide unprecedented precision for the construction of the iconic 'Cerro de Trincheras' volcanic hill terraces in Sonora, Mexico. By measuring the accumulation of cosmogenic isotopes on the rock surfaces since they were first quarried and stacked, researchers have narrowed the primary construction phase to between 1080 and 1120 CE, significantly earlier than previous estimates based on stylistic ceramic analysis.
The research team suggests that this refined chronology correlates perfectly with a major regional demographic shift in the Sonoran Desert. The data indicates that the massive engineering effort required to transform the hillside into a defensive and agricultural hub was a direct response to a 20-year precipitation surge that allowed for the expansion of maize cultivation in high-altitude volcanic soils.