The ⁴⁰Ar/³⁹Ar chronology of caldera formation, intrusive activity and Mo-ore deposition near Questa, New Mexico
— Gerald K. Czamanske, K. A. Foland, F. A. Kubacher, and J. C. Allen

⁴⁰Ar/³⁹Ar geochronologic techniques have been applied to the Questa, New Mexico, area to constrain the timing of magmatic events. The results document intrusive activity, commencing in the north and concluding in the south, over a period of 7 million years. After caldera formation and eruption of The Amalia Tuff at 25.7 ± 0.1 Ma, an episode of widespread intrusive activity, concentrated along the southern caldera margin, occurred at 24.65 ± 0.1 Ma. Deposition of coarse-grained molybdenite ore in the Sulphur Gulch pluton occurred some 0.4 million years later. The magmatic system was still capable of depositing Mo after emplacement of the southernmost, Lucero Peak pluton at 18.5 ± 0.1 Ma.