GEOLOGY OF THE D CROSS MOUNTAIN QUADRANGLE, SOCORRO AND CATRON COUNTIES, NEW MEXICO.
Abstract
Approximately 5000 ft (1525 m) of strata crop out in the D Cross Mountain quadrangle in west-central New Mexico. The oldest strata are red shales and sandstones of the Chinle Formation (Late Triassic) that accumulated on an extensive, low-lying, coastal plain in a meandering stream complex. Jurassic age strata, if deposited in the area, were subsequently eroded due to uplift of the Mogollon Highlands and north-northwest tilting of the area during the Jurassic.
The basal Dakota Sandstone was deposited by laterally planing, meandering streams before regional subsidence during the Cenomanian resulted in the initial encroachment of the mid-continent Cretaceous seaway into the Acoma embayment.
The area oscillated between paralic and coastal non-marine environments for the remainder of the Cretaceous Period. As a result, a complex sequence of dark, offshore marine muds of the Mancos Shale interfinger to the west with coastal marine and fluvial sandstones and shales of the Dakota, Tres Hermanos, Gallup, and Crevasse Canyon Formations.
Northeast-directed compressional forces associated with the Laramide orogeny deformed the strata into a series of broad open folds at the close of Cretaceous time. Pebble conglomerates and arkosic sandstones of the Baca Formation (Eocene) were eroded from the Zuni Mountains, transported to the southeast in a fluvial channel-floodplain complex, and accumulated in an east-trending, elongate, structural low.
A thick cover of volcanic and volcaniclastic rocks spread over the area during the Oligocene. Lithic-crystal and crystal-lithic tuffs and debris flows of the Spears Formation were derived from a major volcanic center located south of the D Cross Mountain quadrangle.
After cessation of volcanism, sediments were stripped from this volcanic highland and accumulated in a northward extending alluvial fan complex. The Miocene (?) conglomerate of Rock Tank Canyon is a fanglomerate that was derived principally from erosion of Spears tuffs.
The dominant structure of the area is a south-dipping homocline formed as the result of uplift of the Colorado Plateau. The continuity of the homocline is, however, broken by a series of Neogene normal faults that formed in response to the opening of the Rio Grande rift. Volcanic necks and plugs cropping out on D Cross Mountain and Blue Mesa were emplaced during the Late Tertiary and appear to post-date uplift of the Plateau.
Subject Area
Geology
Recommended Citation
ROBINSON, BOB RUSSELL, "GEOLOGY OF THE D CROSS MOUNTAIN QUADRANGLE, SOCORRO AND CATRON COUNTIES, NEW MEXICO." (1981). ETD Collection for University of Texas, El Paso. AAI8121976.
https://scholarworks.utep.edu/dissertations/AAI8121976