Upper Paleozoic stratigraphy around the Sierra Nacimiento, San Pedro Mountains, and Jemez Mountains, Northern New Mexico
— Spencer G. Lucas and Karl Krainer, [eds.]

Abstract—Upper Paleozoic (Mississippian, Pennsylvanian, and Permian) strata are exposed around the Sierra Nacimiento, San Pedro Mountains, and Jemez Mountains in northern New Mexico. At scattered outcrops, the Mississippian rocks are assigned to the Arroyo Peñasco Formation, overlain locally by the Log Springs Formation. In the Guadalupe Box area, the Lower Pennsylvanian Osha Canyon Formation overlies Mississippian strata. The Middle Pennsylvanian Sandia Formation overlies the Osha Canyon Formation and crops out at various other locations where it overlies Proterozoic basement, Mississippian strata, or the Osha Canyon Formation. The Middle Pennsylvanian Gray Mesa Formation overlies the Sandia Formation at all outcrops where both units are present. The uppermost Pennsylvanian strata in the Sierra Nacimiento-Jemez Mountains are assigned to the Middle-Upper Pennsylvanian Guadalupe Box Formation. The Permian section begins with the Abo Formation, overlain by the Yeso Group, which consists of the De Chelly Sandstone overlain by the San Ysidro Forma-
tion. The uppermost Permian strata in this region belong to the Glorieta Sandstone. Microfossils (primarily foraminiferans) and invertebrate macrofossils (primarily brachiopods) assign the Arroyo Peñasco Formation an Early-Middle Mississippian (Osagean-Meramecian) age, the Log Springs Formation a Late Mississippian (Chesterian) age, the Osha Canyon Formation an Early Pennsylvanian (Morrowan) age, the Sandia Formation an early Middle Pennsylvanian (Atokan) age, the Gray Mesa Formation a late Middle Pennsylvanian (Desmoinesian) age, and the Guadalupe Box Formation a late Middle Pennsylvanian-Late Pennsylvanian (Desmoinesian-Virgilian) age. Diverse data, most of it from outside of the Sierra Nacimiento-San Pedro Mountains-Jemez Mountains, indicate the Abo Formation is of early Early Permian (Wolfcampian) age, and the Yeso Group and Glorieta Sandstone are of late Early Permian (Leonardian) age.