Paleotectonics of the Late Paleozoic Penasco uplift, Nacimiento region, northern New Mexico
Lee A. Woodward
The late Paleozoic Penasco uplift was a north-trending basement block that approximately coincides with the present Sierra Nacimiento. Rise of the uplift began after deposition of the Lower Pennsylvanian (Morrowan) Osha Canyon Formation and possibly during deposition of the Middle Pennsylvanian (Atokan) Sandia Formation, which appears to thin depositionally toward and is absent along the axis of the uplift. Principal orogenic rise of the uplift is recorded in coarse clasts of Precambrian rocks in the Middle and Upper Pennsylvanian Madera Formation. A growth fault, inferred to have been active along the southwest part of the uplift during Madera time, may have bounded the entire west side of the uplift. Clastic debris eroded from Precambrian rocks of the uplift during this time was shed into adjacent marine, carbonate basins. Lower Permian (Wolfcampian) strata of the terrestrial Abo Formation appear to thin locally across the uplift, suggesting that the uplift retained positive tendencies despite being buried by continental deposits. Limited thickness data for the Lower Permian (Leonardian) Yeso Formation may indicate that the north end of the uplift was slightly positive at this time. Rise of the uplift ceased prior to deposition of the Upper Triassic Chinle Group.
- Woodward, Lee A., 1996, Paleotectonics of the Late Paleozoic Penasco uplift, Nacimiento region, northern New Mexico, in: The Jemez Mountains Region, Goff, Fraser; Kues, Barry S.; Rogers, Margaret Ann; McFadden, Les D.; Gardner, Jamie N., New Mexico Geological Society, Guidebook, 47th Field Conference, pp. 107-113.