New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/13 The Deming axis, southeastern Arizona, New Mexico and Trans-Pecos Texas Gregory L. Turner, 1962, pp. 59-71 in: Mogollon Rim Region (East-Central Arizona), Weber, R. H.; Peirce, H. W.; [eds.], New Mexico Geological Society 13th Annual Fall Field Conference Guidebook, 175 p. This is one of many related papers that were included in the 1962 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. 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TURNER The Pure Oil Company, Houston, Texas The Deming axis is a major linear tectonic element As indicated on Figure 1, the Deming axis seems to extending from southeastern Arizona to Trans-Pecos Texas. consist of a chain of five lesser tectonic features: the Van The trend of this axis is partially expressed by a chain of Horn, Florida, Burro, Graham and Florence uplifts . The five lesser structural units; the Van Horn uplift in western individuality of these uplifts is only relative, although each Texas, the Florida and Burro uplifts in southwestern New seems to have become locally prominent during one or Mexico, and the Graham and Florence uplifts in south- more intervals of geologic time. Structural and strati- eastern Arizona. The Deming axis seems to have been graphic descriptions have been published for the Van Horn, initiated during Mississippian time, and its presence has had Florida, and Burro uplifts (see bibliography). The features a significant effect on the subsequent sedimentary and herein referred to as the Graham and Florence uplifts are structural patterns of this area. These features are illus- previously undescribed. trated by paleogeographic maps of the Paleozoic and The Graham uplift centers around the Precambrian Mesozoic, and paleogeologic maps of outcrop patterns de- mass of the Pinaleno Mountains and is named for Mt. veloped during intervals of major tectonism and erosion. Graham, the highest peak in the range. Significant local The general north-south strike of Tertiary structures and uplift and erosion occurred in the area of this element present-day topographic features in this region are de- during the Late Jurassic "Nevadan" and Late Cretaceous flected to a northwest-southeast trend across the Deming to early Tertiary "Laramide" orogenies. The effect of axis, and this is the basis for the concept of the Texas Nevadan deformation has been mapped in the Dos Cabe- lineament. Lateral continuations of the Deming axis be- zas and northern Chiricahua Mountains, where Cretaceous yond the area of investigation are open to speculation. sediments overlap eroded Paleozoic rocks and locally rest An analysis of the regional structure and stratigraphy on Precambrian granite and schist. Renewed uplift and of southern Arizona and New Mexico, western Texas and erosion during Laramide time is evidenced by the presence northern Sonora and Chihuahua, Mexico, has revealed the of Late Cretaceous and Tertiary volcanics resting uncon- presence of a major linear tectonic element which is here formably on Mesozoic, Paleozoic and Precambrian rocks termed the Deming axis. This feature can be traced from in the Dos Cabezas, Pinaleno, Santa Teresa, Turnbull and the vicinity of the town of Florence in south-central Arizona Mescal Mountains. to the area of Van Horn in Trans-Pecos Texas, and has Nevadan and Laramide movement on the Florence up- been named from Deming, New Mexico, which is near the lift can be interpreted from field work in the ranges to the center of the area of investigation. The Deming axis east and south of the city of Florence, Arizona. Nevadan seems to have been initially developed during Mississippian tectonism is recorded by the occurrence of Cretaceous sedi- time and its presence has had a , significant effect on the ments and volcanics unconformably overlying Paleozoic and sedimentary and structural patterns of the late Paleozoic, Precambrian beds in the Black, Santa Catalina, Waterman Mesozoic and Tertiary. and Vekol Mountains. Broad uplift and erosion of Lara- The evolution of the Deming axis can best be observed mide age is evidenced in the Superior area, and the Tor- through the construction of paleogeologic and paleotec- tilla, Black, Tortolita, Tucson, Silver Bell, Vekol and Silver tonic maps for critical parts of the stratigraphic sequence. Reef Mountains where the Cretaceous-Tertiary volcanic The accompanying illustrations are generalized summaries suite rests on older rocks of various ages. Sedimentary of a series of maps that were prepared, for the most part, rock outcrops are rare in the region to the west and north- from a detailed survey of published and unpublished litera- west of Florence, and the western limit of this uplift can- ture on this region, and an examination of available well not be determined. control. Some segments have been compiled from field Separation between the Florence and Graham uplifts, observations . For reference purposes, the trend of the and between the Graham and Burro uplifts, is a matter of Deming axis is indicated by a dashed line (D—A) extend- conjecture. The proof is hidden beneath the piles of Ter- ing across each map. A complete documentation of the tiary volcanics forming the Galiuro and Peloncillo Moun- control data used in assembling these maps would cover tains. Perhaps the best evidence is the mountains them- several hundred references. The appended bibliography selves, with the volcanic rocks in these ranges being topo- has been selected to substantiate only the structural ele- graphically and structurally lower than the Precambrian on ments critical to the theme of this short note. Mt. Graham. Figure 1 illustrates the regional trend of the Deming Evidence for a Precambrian expression of the Deming axis from south-central Arizona to Trans-Pecos Texas. An axis is inconclusive. A zone of east-west trending Pre- extension of this axis to the west of the map area has not cambrian structures is certainly present in the core area of been established, as the structural and stratigraphic history the Van Horn uplift in Texas. However, through southern of southwestern Arizona is still imperfectly known. An New Mexico and Arizona the dominant lineations within eastward trace is likewise obscure due to the welter of Precambrian exposures are northeast-southwest. Probably Paleozoic, Mesozoic and Cenozoic structural events of the Deming axis is not underlain throughout its entire length western Texas and northern Mexico. Even along the known by a significant basement structural element. trend of the axis the complete understanding of its geologic Figure 2 depicts the general paleogeology of early history awaits the results of additional field work. Paleozoic time. This region appears to have been a part 4 0 O z O W SOCORRO ni 2 0 c • 3 PHOEN▪ -IX 0 ROSWELL FLORENC / 0 0,9 TUCSO▪ N-- 0 soiviZoo,v4 /3,1 DOUGLAS CE NTRAL STA BLE REGION EW MEXICO TEXAS r TOBOSA BASIN as Cr zaOr rU FIGURE 2 EARLY PALEOZOIC PALEOGEOGRAPHY NEW MEXICO GEOLOGICAL SOCIETY c% THIRTEENTH FIELD CONFERENCE 63 of the southwestern extension of the Central Stable region southeastern Arizona and southwestern New Mexico, the of the North-American continent. The Defiance-Zuni and northwest-trending Pedregosa basin began to form, and Pedrenal positive areas may have been present as local the alignment of its northeastern margin provides an ex- upwarps on this platform, but this is by no means certain. pression of the tectonic development of the Deming axis Cambrian deposits are thin or absent over most of ( Figure 4). The effect of this axis on sedimentation is southern New Mexico and western Texas. However, they revealed by the thick, massively-bedded deposits of Early thicken to the southwest across Arizona and Sonora to- Mississippian limestone found in the Pedregosa basin which wards the Paleozoic Sonoran geosyncline, and to the north- contrast with the thinner, somewhat more clastic, occa- west toward the Cordilleran geosyncline. Cambrian beds sionally reef-bearing units found to the north and north- also thicken to the southeast across Texas into a seaway east of the axis.