Geology of Organ Mountains and southern San Andres Mountains, New Mexico

Seager, William R.

doi:10.58799/m-36

Cited by 33 publications

(45 citation statements)

References 65 publications

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“…Therefore, usage of the name Starvation Draw member should be dropped. The Lobo Formation probably is correlative (in part or as a whole) to the Love Ranch Formation (Kottlowski et al, 1956;Seager, 1981) in south-central New Mexico, the Ringbone Formation (Zeller, 1970) in the Little Hatchet Mountains, the Little Hat Top Fanglomerate (Zeller, 1975;Reiter, 1980) in the Alamo Hueco Mountains, the Cowboy Spring Formation-Timberlake Fanglomerate (Zeller and Alper, 1965;Elston and Erb, 1977) in the Animas Mountains, the unnamed conglomerate along the northeast side of the central Cedar Mountains, and the limestone-cobble conglomerate in the west Lime Hills. The Lobo may be in part correlative to the Fort Crittenden Formation (Stoyanow, 1949;Hayes, 1970) in southeastern Arizona.…”

Section: Lobo Formationmentioning

confidence: 99%

Geology of the Florida Mountains, southwestern New Mexico

Clemons¹

1998

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The Florida Mountains are an eastward-tilted Basin and Range fault block approximately 24 km (15 mi) southeast of Deming. The mountains are surrounded by a broad bajada that slopes gently into the Mimbres Basin. Sediments conceal the range-bounding faults except at the northwest end. Ephemeral streams are continuing the erosive processes that have reduced the exposed bedrock area to less than one-half of its initial size.The oldest rocks exposed in the Florida Mountains are Precambrian hornblende and granitic gneisses exposed only north of Capitol Dome. An Upper Cambrian pluton intruded an andesitic to basaltic volcanic sequence producing the hornblende and pyroxene hornfels common in the western and southern parts of the mountains. The alkali-feldspar plutonic rocks are granite at the northern and southern ends of the range and syenite and quartz syenite in the central part. These shallow plutonic rocks and hornfels were unroofed before deposition of a diamictite that, in turn, was mostly eroded preceding deposition of the Bliss Sandstone in Early Ordovician time. Approximately 4,100 ft of Paleozoic rocks that crop out in the southeastern Florida Mountains include, in ascending order: Bliss Sandstone, El Paso Formation, Montoya Formation, Fusselman Dolomite, Percha Shale, Rancheria Formation, and Hueco Formation. No Mesozoic rocks are present except possibly the basal beds of the Lobo Formation, the bulk of which was deposited penecontemporaneously with Laramide deformation during Paleocene and early to middle Eocene times. Extensive andesitic to rhyolitic volcanism from middle Eocene to early Miocene times accounted for the thick Rubio Peak volcaniclastic section forming Florida Peak, as well as the ash-flow tuff, air-fall tuffs, flow-banded rhyolite, basaltic andesite, and dacite in the Little Florida Mountains. Thick rhyolite fanglomerates in the Little Florida Mountains and alluvial conglomerates forming an apron around the mountains have been deposited as the mountain block was uplifted approximately 213 m (7,000 ft) since early Miocene.The south Florida Mountains fault is a northwest-trending, high-angle reverse fault that places Upper Cambrian granite against rocks as young as basal Lobo Formation. Multiple, small thrust faults exhibit younger-over-older rocks relations and produce tectonic elimination of strata. A few show older-over-younger relations. Current studies demonstrate that Laramide deformation in the Florida Mountains is not a continuation of the Cordilleran overthrust belt. Evidence suggests that the deformation resembles the basement-cored uplifts of the Rocky Mountain foreland, with possibly some strike-slip components.Hydrothermal alteration and low-grade mineralization are widespread in the Florida and Little Florida Mountains. Relatively limited activity has produced manganese, zinc, lead, silver, copper, barite, and fluorite ores. Most production of copper, zinc, lead, and silver ores was from shallow oxidized veins, but small amounts of chalcopyrite accompany fluorite and barite in deeper veins. The age of mineralization is believed to be late Tertiary. Although the mountains had been mapped before (by Darton in 1916 and by Corbitt in 1971), questions about interpretations of several aspects of the geology of the Florida Mountains had not been settled: Are the plutonic rocks of Precambrian, Ordovician, Mesozoic, or some other age? Are the plutonic rocks related, or were they formed by multiple episodes of plutonism? Are the gabbros and diorites (hornfelses) older or younger than the granites and syenites? What is the origin of the south Florida Mountains fault and associated thrust faults? Are they part of the Cordilleran overthrust belt? Clemons spent nearly two decades mapping in the Florida Mountains trying to answer these (and other) questions.Rather than hold all the data until completion of mapping and laboratory studies, several progress reports and four geologic maps (GM-52, Geology of Florida Gap quadrangle, 1982; GM-58, Geology of Gym Peak quadrangle, 1983; GM-56, Geology of Capitol Dome quadrangle, 1984; and GM-59, Geology of South Peak quadrangle, 1985) were published previously. Terminology, interpretation, and ideas in this report represent revisions from Clemons' earlier publications.

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Section: Lobo Formationmentioning

confidence: 99%

Geology of the Florida Mountains, southwestern New Mexico

Clemons¹

1998

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“…The Palm Park Formation was named by Kelley and Silver (1952) for exposures in Palm Park, located adjacent to Red House Mountain in the southern part of the Caballo Mountains. Mapped extensively throughout south-central New Mexico, the formation has also been correlated with the Rubio Peak Formation in the Silver City region (Elston, 1957), the Spears Formation in the Socorro-Datil region (Tonking, 1957;Osburn and Chapin, 1983), and with the Orejon Andesite and Cleofas Andesite of the Las Cruces area (Dunham, 1935;Seager et al, 1976;Seager, 1981). In the Caballo Mountains, the formation crops out widely in Apache Valley and in the McLeod syncline, as well as in Palm Park.…”

Section: Palm Park Formationmentioning

confidence: 93%

“…The Gallup is absent at Hidden Ta nk, because of Laramide ero sion. The Gallup Sandstone has also been described in the Love Ranch area of the southern San Andres Mountains, which con stitutes the southernmost exposure of the formation (Seager, 1981). Throughout south-central New Mexico, the Gallup Sandstone is time transgressive, ranging in age from early late Turonian to early Coniacian and becoming younger to the east northeast (Molenaar, 1983a,b;Cobban and Hook, 1989).…”

Section: Gallup Sandstonementioning

confidence: 99%

“…time, the precise age of the uncon formity is uncertain. Elsewhere in southern New Mexico, impor tant unconformities of middle Mississippian (post-Osage, pre Meramec) age and latest Mississippian-Early Pennsylvanian (post-Chester, pre-Atoka) age have been identified (Meyers, 1974;Armstrong et al, 1979Armstrong et al, , 1980Harbour, 1972;Seager, 1981). The unconformity in the Caballo area may represent either of these or both.…”

Section: Middle Mississippian-early Pennsylvanian Unconformitymentioning

confidence: 99%

“…The Mancos Shale was named by Cross (1899) for exposures near the town of Mancos in southwestern Colorado, and has been applied extensively throughout New Mexico. The Mancos has been extended as far south as the southern San Andres Mountains, the Burro Mountains, Cooke's Range, and the Silver City area (Seager, 1981;Molenaar, 1983a;Mack et al, 1998b). In south-central New Mexico, the Mancos is divided into a lower Rio Salado Tongue and an upper D-Cross Tongue, separated by the Tres Hermanos Formation (Hook and Cobban, 1981;Molenaar, 1983a;Hook, 1983;Hook et al, 1983).…”

Section: Rio Salado Tongue Of the Mancos Shalementioning

confidence: 99%

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Geology of the Caballo Mountains, New Mexico

Seager¹,

Mack²

2003

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The Caballo Mountains, just south of Truth or Consequences, rise to an elevation of 7,065 feet. Today they are flanked on the west side by Caballo Reservoir and on the east side by the Jornada del Muerto. An extraordinary geologic section is preserved here. Precambrian igneous and metamorphic rocks (granites and schists) provide a view of the Precambrian history of this part of the country, and an extraordinary thickness of sedimentary rocks (whose collective thickness is more than 3.5 miles) gives us an unparalleled picture of the evolution of southern New Mexico. Development of these mountains began with compression and uplift associated with the Laramide orogeny, at the end of the Mesozoic. Since then the complex geologic history of this part of New Mexico has included uplift, erosion, faulting, volcanic activity, continental deposition, and, finally, the development of the Rio Grande rift. That complex geologic history is well documented in this volume. This memoir is the result of many years of study and field work on the part of the authors, who have drawn together in one place this comprehensive description of the region. The volume is heavily illustrated with photographs, maps, stratigraphic sections, and other graphics. It contains both an index and a glossary.

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Distribution and sources of obsidian in the Rio Grande gravels of New Mexico

Church¹

2000

Geoarchaeology

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Geology of Organ Mountains and southern San Andres Mountains, New Mexico

Cited by 33 publications

References 65 publications

Geology of the Florida Mountains, southwestern New Mexico

Geology of the Florida Mountains, southwestern New Mexico

Geology of the Caballo Mountains, New Mexico

Distribution and sources of obsidian in the Rio Grande gravels of New Mexico

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