Tectonic evolution of the Lucero Uplift

The Lucero uplift lies along the western part of the Colorado Plateau and bounds the northwestern edge of the Albuquerque Basin. It preserves a rich geologic history involving a well-exposed upper Paleozoic stratigraphic section and multiple deformational, magmatic, and denudational events. The purpose of this paper is to synthesize EDMAP and STATEMAP mapping and research efforts to highlight developments in our understanding of this region by focusing on two main research locations: Carrizo Arroyo and the Belen travertine quarries owned and operated by New Mexico Travertine, Inc. The Cenozoic deformational history of this part of the western edge of the Rio Grande rift involved the following elements from west to east: (1) Lucero uplift of the eastern Colorado Plateau is a wide region of gently west-dipping (< 10°), undeformed Permian and Triassic rock, (2) the Comanche fault zone is a west-side-up contractional fault zone that developed from approximately east-west compression during the Laramide orogeny, (3) the Comanche deformation domain (~500-m-wide) is made up of steeply-dipping Paleozoic and Mesozoic strata (the steep limb of the Comanche monocline), (4) newly-dated 27.5 Ma igneous intrusions cross-cut steeply dipping beds, (5) low-angle normal faults preserved in the deformation domain are early, rotated rift normal faults, (6) the Santa Fe normal fault forms the eastern side of the Comanche deformation domain and the western boundary of the Rio Grande rift; it cross cuts and down-drops the synclinal hinge of the monocline deep into the rift, (8) the Comanche deformation domain was a zone of fluid flux of deeply-sourced fluids that mixed with meteoric recharge and resulted in travertine mounds and platforms that were deposited by carbonic, saline springs and resulted in world-class travertine deposits in the Belen quarry area, (9) the 3.7 Ma Mesa Carrizo basalt erupted from vents on the Colorado Plateau and flowed southeast across a low relief surface (Ortiz surface) at a time when there was little relief on the western rift flank, (10) the Belen travertine quarries consist of several Quaternary travertine platforms that are cut by multiple sets of rift-parallel and rift-perpendicular extensional calcite veins that show strain rates over the last 2 Ma that are one to two orders of magnitude higher than present-day strain rates measured from GPS, and (11) Carrizo Arroyo, itself, is a spectacular 183-m deep canyon tributary to the Rio Puerco that has been incised at a rate of 50 m/Ma over the last 1 Ma due to river system integration, climate, or base level lowering in the Rio Grande. 185 HISTORICAL BACKGROUND As summarized in Duschatko’s (1953) Atomic Energy Commission Report, the Lucero Mesa area was first mapped by Darton (1928), who recognized a subvertical fault system that separates undeformed Paleozoic and Mesozoic strata on the west from the Rio Grande rift valley to the east. Kelley and Wood (1946) recognized the deformation zone to include faults of likely different age, the presence of low-angle faults that they interpreted to be Laramide thrust faults, and the likelihood of fault reactivation. Wright (1946) mapped the Carrizo Arroyo area at 1:12,000 but focused on the Tertiary geology and omitted most of the structural complexities. Duschatko (1953) mapped structures in great detail and highlighted the narrow N-S deformation zone of complex faulting and jointing that he interpreted to be due to multiple movements. His description below is similar to our interpretation except that we interpret the Laramide monocline to be the result of west-sideup (not east-side-up) reverse fault displacement. His summary of the evolution of the structures is well worth reproducing here, some five decades later: “The writer believes that the most satisfactory explanation of all these phenomena lies in the hypothesis that during an early period of deformation (possibly late Cretaceous or early Tertiary) a very sharp monocline developed along intersecting trends from the south edge of Gray Mesa to the Ladrons. Both the eastern and western limbs of this flexure were very nearly horizontal and the intervening flank was nearly vertical or, locally, slightly overturned towards the west. Possibly the flexure was the expression in the sediments of displacement along major crustal fractures emanating from below with the eastern block moving up. Penecontemporaneous fracturing of the steep flank and subsequent foundering of the east block primarily along the same zone of weakness during a second period of deformation accounts not only for the presence of infaulted pre-Cambrian rocks, but also for the presence of the Permian. These stages in the structural history are illustrated (somewhat diagrammatically) in Plate X” (pg. 28-29).