⁴⁰Ar/³⁹Ar ages of Palm Park volcanic rocks, south-central New Mexico
— F.C. Ramos and Heizler, M.T., Hampton, B.A.

Volcanic rocks of the Palm Park Formation, exposed in multiple locations throughout south-central New Mexico, are composed of volcanic and volcanoclastic rocks that are lithologically and compositionally variable at scales within individual exposures and between exposures at different localities. ⁴⁰Ar/³⁹Ar ages of plagioclase and biotite from Palm Park volcanic rocks range from ~43.5 to ~39.5 Ma. These eruption ages can be used to correlate exposures throughout south-central New Mexico and are generally consistent with zircon ages from the same units. Overall, these ages constrain the timing of magmatism related to the Laramide Orogeny as it transitioned to magmatism associated with the ignimbrite flare-up. This is a poorly studied portion of the middle Tertiary magmatic history of southern New Mexico and Palm Park Formation volcanic units provide an excellent opportunity to refine our knowledge of the geologic history of this time interval.