Geology of the Moreno Valley, Colfax County, New Mexico
Colpitts, Robert M., Jr. and Clay T. Smith
This paper presents a summary of the geology of the Moreno Valley based on published reports, geologic maps and unpublished theses. Rocks in the Moreno Valley range in age from Precambrian to Quaternary with thick sections of upper Paleozoic (Pennsylvanian-Permian) and lesser thicknesses of Mesozoic and Tertiary strata. All units have been disrupted by folding and faulting representing several periods of deformation ranging in age from Precambrian to Tertiary. Beginning in the latest Cretaceous, initial broad folding and uplift were followed during the early Tertiary by tighter folding, and thrust and reverse faulting. These structures were cut by later high-angle normal faults, some related to development of the present Sangre de Cristo Mountains and the adjacent Rio Grande rift. Minimum shortening in an east-west direction of as much as 2.7 km is estimated for the folding and thrust faulting. Stratigraphic throws on transverse normal faults reach nearly 3900 m. Displacements on valley-parallel normal faults are less than 100 m. Mid- to late Tertiary intrusive and extrusive rocks have had a major influence on the development of the present-day valley. The present Moreno Valley developed from blockage of the ancestral Coyote Creek drainage by early Pliocene (5 Ma) lava flows and the integration of Moreno and Cieneguilla Creek drainages to the present Cimarron River.
- Colpitts, Robert M., Jr.; Smith, Clay T., 1990, Geology of the Moreno Valley, Colfax County, New Mexico, in: Tectonic development of the southern Sangre de Cristo Mountains, New Mexico, Bauer, Paul W.; Lucas, Spencer G.; Mawer, Christopher K.; McIntosh, William C., New Mexico Geological Society, Guidebook, 41st Field Conference, pp. 219-228.