Quaternary age Of The Gatuña Formation at Livingston Ridge
— Snir Attia, Matthew T. Heizler, and Julia Ricci

The age, internal stratigraphy, and regional context of the late Cenozoic Gatuña Formation in southeastern New Mexico remain uncertain. Previous workers have extended the original Gatuña stratigraphic concept to include essentially any late Cenozoic deposits along the Pecos Valley in eastern New Mexico and down into western Texas. The only absolute age constraint for strata unquestionably assigned to the Gatuña Formation comes from an outcrop along Livingston Ridge in Nash Draw (Eddy County, NM), where an interbedded volcanic ash has been correlated with the ca. 0.63 Ma Lava Creek B eruption of the Yellowstone caldera. Previous workers proposed a diachronous Gatuña Formation with a Miocene to Pliocene lower section, supported by interpretation of a pedogenic carbonate horizon farther south at Pierce Canyon as an intraformational equivalent to the Neogene Ogallala caprock of the High Plains. Field relations documented during recent geologic mapping in the Pierce Canyon area are inconsistent with the existence of such an intraformational caliche. New detrital sanidine 40Ar/39Ar age analyses from Gatuña Formation sediments underlying the Lava Creek B ash at Livingston Ridge yield numerous Quaternary ages, with ~1.3–1.6 Ma youngest detrital grain ages providing a ca. 1.3 Ma (n = 3) maximum depositional age. The Gatuña Formation at this site is thus entirely Quaternary. No existing evidence requires a pre-Quaternary depositional age for the Gatuña Formation in southeastern New Mexico, but neither does any existing data preclude possible Miocene-Pliocene ages for at least some Pecos Valley deposits.