Stratigraphy and provenance of upper Cretaceous and Paleogene strata of the western Sierra Blanca Basin, New Mexico
Steven M. Cather
A sampled reference section about 1200 m thick in the western Sierra Blanca basin contains strata ranging in age from Late Cretaceous to late Eocene—early Oligocene(?). Stratigraphic units include, in ascending order, the Crevasse Canyon Formation (probably the Ash Canyon Member), the Cub Mountain Formation, the Sanders Canyon Formation (new name), and the Walker Andesite Breccia of the Sierra Blanca Volcanics. With the exception of a disconformity at the base of the Cub Mountain Formation, which represents a lacuna that spans at least the entire Paleocene, contacts between the stratigraphic units appear to be gradational. A marked similarity in detrital composition between the Crevasse Canyon Formation and the lower part of the Cub Mountain Formation suggests that much of the basal Cub Mountain was recycled from underlying Cretaceous rocks. Provenance data from the upper part of the Cub Mountain Formation document the unroofing of Paleozoic and crystalline basement sources as Eocene tectonism proceeded. The increased influx of volcaniclastic grains in the distally derived sandstone and mudstone of the Sanders Canyon Formation records the onset of Tertiary volcanism in areas to the south and southwest. Debris-flow breccias of the Sierra Blanca Volcanics at the top of the reference section herald the beginning of local volcanism nearby to the east or southeast.
- Cather, Steven M., 1991, Stratigraphy and provenance of upper Cretaceous and Paleogene strata of the western Sierra Blanca Basin, New Mexico, in: Geology of the Sierra Blanca, Sacramento and Capitan Ranges, New Mexico, Barker, James M.; Kues, Barry S.; Austin, George S.; Lucas, Spencer, G., New Mexico Geological Society, Guidebook, 42nd Field Conference, pp. 265-275.