Stratigraphy and structure of the Laramide Carthage - La Joya Basin, central New Mexico
Steven M. Cather
The elongate, north-northwest trending Carthage–La Joya basin of central New Mexico developed in the middle Eocene, late in the Laramide orogeny. Sedimentary strata in the basin consist of a fluviatile red-bed succession of sandstone, conglomerate, and minor mudstone as much as ~300 m thick. Sediments were derived mostly from the nearby Sierra uplift to the west, and were deposited on an east-facing, braided-alluvial piedmont system. In the northern part of the Carthage–La Joya basin, however, scattered deposits of a southwest-facing piedmont system are preserved. These deposits may provide a depositional record of the Montosa uplift to the northeast. An axial-river facies stratigraphically intervenes between deposits of the opposing piedmont facies in parts of the northern basin and overlies Mesozoic strata on the east flank of the basin, where it shows evidence for southeasterly paleoflow. These axial-river deposits are dominated by well-rounded, varicolored quartzite clasts that appear to have been derived from the Mogollon Highland far to the west in central Arizona, and record an extrabasinal river that at times spilled over the Sierra uplift from the Baca basin.
The Carthage–La Joya basin region is extraordinarily complex structurally, but relatively few structures can be definitively shown to be Laramide. These include (1) the reverse faults and folds of the Amado–Cañas structural zone in the west-central part of the basin, (2) the Stapleton thrust fault in the northern part of the basin, (3) two northeast-striking systems of high-angle Laramide faults in the northern part of the basin (the Parida and Milagro structural zones) that may be related to the dextraloblique Montosa fault system to the east, and (4) widespread, low-angle, top-east normal faults in Permian evaporite strata.
- Cather, Steven M., 2009, Stratigraphy and structure of the Laramide Carthage - La Joya Basin, central New Mexico, in: Geology of the Chupadera Mesa, Lueth, Virgil W.; Lucas, Spencer G.; Chamberlin, Richard M., New Mexico Geological Society, Guidebook, 60th Field Conference, pp. 227-234.