Depositional and erosional features outline the late Paleozoic Pedernal uplift as a narrow northward-elongated landmass, connected southward with the Diablo platform and northeastward with the Sierra Grand arch and Amarillo-Wichita uplift. During pre-Pennsylvanian Paleozoic time, north-central and central New Mexico was periodically uplifted epeirogenically, but this "massif" bears little resemblance to late Paleozoic Pedernal uplift. Pedernal should not be applied to the massif in east-central New Mexico (southern part of Sierra Grande arch).

Ordovician, Silurian, and Mississippian strata probably were deposited in most of New Mexico and adjoining areas, and Devonian beds in most of southern and western New Mexico, but were removed from large areas during subsequent erosion periods. Early Ordovician El Paso-Manitou was eroded in Middle Ordovician time; later Ordovician Cable Canyon-Harding and Montoya-Fremont as well as Silurian Fusselman Dolomite were partly removed during Late Silurian-Early Devonian time; and only a remnant of Mississippian was left in central New Mexico by erosion during Late Mississippian-Early Pennsylvanian time. Erosional and sedimentational patterns trend east-west for earlier Paleozoic strata, with a positive-trending feature in north-central New Mexico, contrasting with Pennsylvanian and early Pe mian northward trends related to the Pedernal uplift and its adjoining basins, Orogrande and Estancia on the west, and Delaware on the southeast.

The northern New Mexico massif supplied some Cambrian sands, some Middle Ordovician Simpson sand and silt, and Late Devonian and Early Mississippian silt and clay. The Pedernal uplift area in south-central New Mexico was covered by early and middle Paleozoic seas, and did not become a detritus-source upland until Early Pennsylvanian time. During Pennsylvanian and early Wolfcampian time it provided much sediment to flanking basins; most of the uplift was worn down and was buried by floods of northern redbed material during late Wolfcampian time. Only remnant hills remained in the sandy seas of Leonardian time.

End_of_Article - Last_Page 197------------