Aztec Sandstone

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Aztec Sandstone
Stratigraphic range: Early Jurassic
RedRocksDistortedBeds.JPG
Outcrop of the Aztec Sandstone at Red Rock Canyon National Conservation Area near Las Vegas, Nevada
Type Sedimentary
Underlies Willow Tank Formation [1]
Overlies Chinle Formation
AreaNevada, [2] Arizona, California [3]
Thickness2,100 ft (640 m) in Goodsprings quadrangle [2]
2,500 ft (760 m) in Muddy Mountain area [1]
Lithology
Primary sandstone
Other arenite, sand
Location
Coordinates 35°24′N115°30′W / 35.4°N 115.5°W / 35.4; -115.5
Approximate paleocoordinates 20°48′N53°24′W / 20.8°N 53.4°W / 20.8; -53.4
Region Mojave Desert
Country United States
Type section
Named byD. F. Hewett [2]
Year defined1931
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Aztec Sandstone (the United States)
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Aztec Sandstone (California)

The Aztec Sandstone is an Early Jurassic geological formation of primarily eolian sand from which fossil pterosaur tracks have been recovered. [4] The formation is exposed in the Mojave Desert of Arizona, California and Nevada. Aztec Sandstone is named after the Aztec Tank, [5] a lake in the Spring Mountain region of Nevada.

Contents

Description

The Aztec Sandstone is made up of two units. The lower resistant sandstone unit (100 metres (330 ft) thick) is tan to off-white in outcrops but pinkish in fresh exposures. Cross-bedded lenses can easily be observed. Frosted and pitted quartz grains well-cemented by silica are described by Evans in 1958 and 1971. The upper and less resistant unit (200m thick) consists of alternating white quartz arenites and red to brown silty sands. [6]

Vertebrate paleofauna

The formation has provided the following ichnofossils attributed to vertebrates: [4]

Ichnofossils of the Aztec Sandstone
GenusSpeciesLocationMemberAbundanceNotesImages
Anchisauripus [7] Reclassified as Grallator
Brasilichnium
Grallator [8]
Grallator.jpg
Navahopus
Octopodichnus
Pteraichnus [9]
Skolithos
Skolithos.jpg
Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

See also

References

  1. 1 2 Longwell, C.R. (1949). "Structure of the Northern Muddy Mountain Area, Nevada". Geological Society of America Bulletin . 60 (5): 923–968. Bibcode:1949GSAB...60..923L. doi:10.1130/0016-7606(1949)60[923:SOTNMM]2.0.CO;2. ISSN   0016-7606. Wikidata   Q60182382.
  2. 1 2 3 Hewett, D.F. (1931). "Geology and ore deposits of the Goodsprings quadrangle, Nevada" (PDF). Geological Survey Professional Paper (162). doi:10.3133/PP162. ISSN   0096-0446. Wikidata   Q61823480. (incl. geologic map, scale 1:62,500)
  3. Jennings, C.W., 1961, Geologic map of California; Kingman sheet: California Division of Mines and Geology, scale 1:250,000
  4. 1 2 Aztec Sandstone at Fossilworks.org
  5. "Geolex — Aztec publications". ngmdb.usgs.gov. Retrieved 2023-03-14.
  6. Mescal Range at Fossilworks.org
  7. Listed as "cf. Anchisauripus" in "Appendix: Summary of the Mesozoic Reptilian Fossils of California," Hilton (2003) p. 265
  8. Listed as "cf. Grallator" in "Appendix: Summary of the Mesozoic Reptilian Fossils of California," in Hilton (2003) p. 265
  9. Lockley, et al. (2008)

Bibliography

Further reading