View source for Aztec Sandstone


{{short description|Early Jurassic geological formation in the Mojave Desert, United States}}
{{Infobox rockunit
| name           = Aztec Sandstone
| image          = RedRocksDistortedBeds.JPG
| caption        = Outcrop of the Aztec Sandstone at [[Red Rock Canyon National Conservation Area]] near Las Vegas, Nevada
| type           = [[Sedimentary Rock|Sedimentary]]
| age            = [[Early Jurassic]]
| period         = Early Jurassic
| prilithology   = [[sandstone]]
| otherlithology = [[arenite]], [[sand]]
| namedfor       =
| namedby        = D. F. Hewett<ref name=Hewett1931>{{Cite Q| Q61823480|author= Hewett, D.F. |author-link=Donnel Foster Hewett}} (incl. geologic map, scale 1:62,500)</ref>
| year_ts        = 1931
| region         = [[Mojave Desert]]
| country        = {{USA}}
| coordinates    = {{coord|35.4|N|115.5|W|display=inline,title}} 
| paleocoordinates = {{coord|20.8|N|53.4|W|display=inline}}
| unitof         = 
| subunits       =
| underlies      = [[Willow Tank Formation]]<ref name=Longwell1949>{{Cite Q|Q60182382|author= Longwell, C.R.|author-link=Chester Ray Longwell}}</ref>
| overlies       = [[Chinle Formation]]
| thickness      = {{convert|2100|ft|m|abbr=on}} in Goodsprings quadrangle<ref name=Hewett1931/><br>{{convert|2500|ft|m|abbr=on}} in Muddy Mountain area<ref name=Longwell1949/>
| extent         =
| area           = Nevada,<ref name=Hewett1931/> Arizona, California<ref>Jennings, C.W., 1961, Geologic map of California; Kingman sheet: California Division of Mines and Geology, scale 1:250,000</ref>
| map            = {{Location map+ | United States#California
| relief = 1
| width   = 250
| float   = center
| places  =
  {{Location map~ | United States#California
  | lat_deg = 35.4
  | lon_deg = -115.5
  | mark = Blue pog.svg
  | marksize = 10
  }}
  {{Location map~ | United States#California
  | lat_deg = 36.4
  | lon_deg = -114.6
  | mark = Blue pog.svg
  | marksize = 10
  }}
}}
| map_caption    =
}}

The '''Aztec Sandstone''' is an [[Early Jurassic]] geological [[Formation (geology)|formation]] of primarily [[Eolianite|eolian]] sand from which fossil [[pterosaur]] [[Trace fossil|tracks]] have been recovered.<ref name=FW>[http://www.fossilworks.org/cgi-bin/bridge.pl?action=displayStrata&geological_group=&formation=Aztec%20Sandstone&group_formation_member=Aztec%20Sandstone Aztec Sandstone] at [[Fossilworks]].org</ref> The formation is exposed in the [[Mojave Desert]] of [[Arizona]], [[California]] and [[Nevada]]. Aztec Sandstone is named after the Aztec Tank,<ref>{{Cite web |title=Geolex — Aztec publications |url=https://ngmdb.usgs.gov/Geolex/UnitRefs/AztecRefs_4626.html |access-date=2023-03-14 |website=ngmdb.usgs.gov}}</ref> a lake in the Spring Mountain region of Nevada.

== Description ==
The Aztec Sandstone is made up of two units. The lower resistant sandstone unit ({{convert|100|m|ft}} thick) is tan to off-white in outcrops but pinkish in fresh exposures. [[Cross-bedding|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 [[arenite]]s and red to brown silty sands.<ref name=FWMescal>[http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&collection_no=52175 Mescal Range] at [[Fossilworks]].org</ref>

== Vertebrate paleofauna ==
The formation has provided the following [[ichnofossil]]s attributed to vertebrates:<ref name=FW/>

{| class="wikitable" align="center"
|-
! colspan="7" align="center" | '''[[Ichnofossil]]s of the Aztec Sandstone'''
|-
! Genus !! Species !! Location !! Member !! Abundance !! Notes !! Images
|-
| style="background:#FEF6E4;" | ''[[Anchisauripus]]''<ref name="hiltonp26a">Listed as "cf. ''Anchisauripus''" in "Appendix: Summary of the Mesozoic Reptilian Fossils of California," Hilton (2003) p. 265</ref>
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" | Reclassified as ''Grallator''
| 
|-
| style="background:#FEF6E4;" | ''[[Brasilichnium]]''
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| 
|-
| style="background:#FEF6E4;" | ''[[Grallator]]''<ref name="hiltonp265g">Listed as "cf. ''Grallator''" in "Appendix: Summary of the Mesozoic Reptilian Fossils of California," in Hilton (2003) p. 265</ref>
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| [[File:Grallator.jpg|center|150px]]
|-
| style="background:#FEF6E4;" | ''[[Navahopus]]''
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| 
|-
| style="background:#FEF6E4;" | ''[[Octopodichnus]]''
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| 
|-
| style="background:#FEF6E4;" | ''[[Pteraichnus]]''<ref name="Lockleyetal2008">Lockley, et al. (2008)</ref>
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| 
|-
| style="background:#FEF6E4;" | ''[[Skolithos]]''
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| style="background:#FEF6E4;" |
| [[File:Skolithos.jpg|center|150px]]
|-
|}
{{paleobiota-key-compact}}

== See also ==
* [[List of fossil sites]]
* [[List of fossiliferous stratigraphic units in California]]
* [[List of fossiliferous stratigraphic units in Nevada]]

== References ==
{{reflist|2}}

=== Bibliography ===
{{commons category|Aztec Sandstone}}
<!--most recent first-->
* {{Cite Q| Q95597606|author=Bonde, J. W.|author2=Varricchio, D. J.|author3=Jackson, F. D.|author4=Loope, D. B.|author5=Shirk, A. M.|editor= E. M. Duebendorfer |editor2= E. I. Smith}}
* Lockley, M.; Harris, J.D.; and Mitchell, L. 2008. "A global overview of pterosaur ichnology: tracksite distribution in space and time." ''Zitteliana''. B28. p.&nbsp;187-198. {{ISSN|1612-4138}}.
* {{Cite Q| Q97000543|author= Porter, M.L.}}
* Hilton, Richard P. 2003. Dinosaurs and Other Mesozoic Reptiles of California. Berkeley: University of California Press. 318 pp.

== Further reading ==
* R. E. Reynolds. 1986. California trackways from the Lower Jurassic Aztec Sandstone. In D. D. Gillette (ed.), First International Symposium on Dinosaur Tracks and Traces. Abstracts with Program 24

{{Chronostratigraphy of Nevada}}

[[Category:Geologic formations of Arizona]]
[[Category:Geologic formations of California]]
[[Category:Geologic formations of Nevada]]
[[Category:Jurassic Arizona]]
[[Category:Jurassic California]]
[[Category:Jurassic geology of Nevada]]
[[Category:Sandstone formations of the United States]]
[[Category:Geologic formations with imbedded sand dunes]]
[[Category:Aeolian deposits]]
[[Category:Ichnofossiliferous formations]]
[[Category:Paleontology in California]]
[[Category:Paleontology in Nevada]]