Lower middle Tertiary rhyolitic to dacitic pyroclastic rocks of the Datil Group, ash-flow tuffs

Regional ash-flow tuffs include Hell's Mesa, Kneeling Nun, Caballo Blanco, Datil Well, Leyba Well, Rock House Canyon, Blue Canyon, Sugarlump, Oak Creek, Bluff Creek, Gillespie, Box Canyon, Cooney and Chiquito Peak Tuffs; the tuffs of Steins Mountain, Black Bill Canyon, Woodhaul Canyon, and Farr Ranch; tuffs of the Organ cauldron; and lower tuffs in the Bell Top Formation. Includes some locally erupted lavas and tuffs within thick intra-caldera units; includes minor volcaniclastic sedimentary units and lavas between thin outflow sheets.
State New Mexico
Name Lower middle Tertiary rhyolitic to dacitic pyroclastic rocks of the Datil Group, ash-flow tuffs
Geologic age Lower Oligocene to upper Eocene (31-36 Ma)
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic (Flow, Pyroclastic-ash flow)Numerous formations of pyroclastics ranging from rhyolitic to dacitic composition.
Minor
Sedimentary > Clastic (Tuffaceous)Includes minor volcaniclastic sedimentary units and lavas between thin outflow sheets.
References
NGMDB product
Counties Catron - Dona Ana - Grant - Hidalgo - Luna - Rio Arriba - Sierra - Socorro - Taos