Open-file Geologic Map - 265
Geologic Map of the McCartys 7.5-Minute Quadrangle, Cibola County, New Mexico

The McCartys quadrangle lies a few kilometers (km) east-southeast of the town of Grants along I40 in northwestern New Mexico. Over half the quadrangle lies on Pueblo of Acoma land, while the remainder is a mix of private ranch land, BLM, and minor state of New Mexico land. The Rio San Jose river valley roughly bisects the quadrangle along an east-west transect. The northeast quarter of the quadrangle lies mainly on the broad, low-relief southern piedmont of Mount Taylor, and is traversed south-southeastward by Rinconada Creek. The northwest quarter of the quadrangle is dominated by Horace Mesa, a broad “prong” of the Mount Taylor highland capped by Plio-Pleistocene basalt flows. The south half of the quadrangle consists of low sandstone-capped mesas separated by broad alluvial valleys. Elevations ranges from about 1,854 meters (m) above mean sea level (amsl) where the Rio San Jose exits the quadrangle to a high of about 2,336 m amsl on Horace Mesa.

Geologically, the quadrangle lies in the Acoma Sag section of the Colorado Plateau along the eastern limb of the McCartys syncline (Woodward, 1982), along or just south of the Jemez lineament and to the south of the Mount Taylor volcanic field and east of the Zuni-Bandera volcanic field. The majority of the quadrangle is underlain by clastic Mesozoic strata capped by a variable thickness of Pliocene to Holocene basalts and Quaternary alluvial cover. Structural relief is generally low.