{{Short description|Triassic geologic formation in New Mexico, United States}}{{Infobox rockunit | name = Salitral Formation | image = Salitral Formation.jpg | caption = Salitral Formation at its type section, near [[Youngsville, New Mexico]]. | type = [[Formation (stratigraphy)|Formation]] | age = {{Geological range|Late Triassic}} | period = Late Triassic | prilithology = [[Shale]] | otherlithology = | namedfor = Salitral Creek | namedby = Wood and Northrop | year_ts = 1946 | region = [[New Mexico]] | country = [[United States]] | coordinates = {{coord|36.1765|N|106.6894|W|display=inline}} | unitof = [[Chinle Group]] | subunits = Piedre Lumbre Member, Youngsville Member | underlies = [[Poleo Formation]] | overlies = [[Shinarump Conglomerate]] | thickness = {{convert|30|m|feet|abbr=on}} | extent = | area = | map ={{Location map+ | United States#New Mexico | relief = 1 | width = 250 | float = center | places = {{Location map~ | United States#New Mexico | lat_deg = 36.176 | lon_deg = -106.689 | mark = Purple pog.svg | marksize = 12 }} }} | map_caption = }}
The '''Salitral Formation''' is a [[Late Triassic]] [[Formation (geology)|geologic formation]] found in north-central [[New Mexico]], primarily the northwestern [[Jemez Mountains]]. It is an older subunit of the [[Chinle Group]] (or formation), overlying the [[Shinarump Conglomerate]] and underlying the [[Poleo Formation]].
==History of investigation== The unit was originally designated as the '''Salitral Shale''' tongue of the [[Chinle Formation]] by Wood and Northrup in 1946, as part of their petroleum survey of the region. It was presumably named for Salitral Creek ({{coord|36.1764797|N|106.6893804|W|display=inline}}).{{sfn|Wood | Northrop |1946}} Lucas and Hunt raised it to formation rank in 1992 in the same study in which they raised the [[Chinle Formation]] to group rank.{{sfn|Lucas | Hunt |1992}} Other authors prefer a lower rank, as the '''Salitral Member''' of the Chinle Formation.{{sfn|Cather|Zeigler|Mack|Kelley|2013}}
==Geology== The formation consists of variegated [[mudstone]]{{sfn|Wood | Northrop |1946}} and is assigned to the lower ([[Bentonite|bentonitic]]) [[Chinle Group]].{{sfn|Stewart|Poole|Wilson|Cadigan|1972}} The Salitral extensively [[intertongues]] with the underlying [[Shinarump Conglomerate]] (formerly known in the Jemez as the [[Agua Zarca Sandstone]]) and pinches out in the [[Abiquiu]] area and in the southern Jemez, where the overlying [[Poleo Formation]] rests directly on the Shinarump.{{sfn|Stewart|Poole|Wilson|Cadigan|1972}}{{sfn|Lucas|Zeigler|Heckert|Hunt|2005}}
The Salitral Formation is time-equivalent to other Chinle strata found further west, occupying the same stratigraphic position. These include the [[Bluewater Creek Formation]] and the [[Blue Mesa Member]] in west-central New Mexico, and the [[Monitor Butte Formation]] and Blue Mesa Member in southeastern [[Utah]]. However, it is not a synonym for any of these formations, being much thinner and having its own distinctive [[lithology]].{{sfn|Lucas|Zeigler|Heckert|Hunt|2005}}
The formation is notable for the presence of [[Septaria|septarian concretions]].{{sfn|Wood | Northrop |1946}}{{sfn|Lucas|Zeigler|Heckert|Hunt|2005|p=116}} [[File:Salitral septarian nodule.jpg|thumb|Septarian nodule from the Salitral Formation]]
===Members=== As a formation, the Salitral consists of two members. The lower '''Piedre Lumbre Member''', named for the Piedre Lumbre Land Grant, is [[sandstone]] and [[siltstone]], olive gray to brown in color, up to {{convert|5|meter|feet|abbr=off}} thick. It tends to form a green slope immediately above the underlying [[Shinarump Conglomerate]]. The upper bed is occasionally prominent as a brownish yellow intraformational [[Conglomerate (geology)|conglomerate]] up to {{convert|1.6|meter|feet|abbr=off}} thick. When present, this is designated the '''El Cerrito Bed'''. The upper '''Youngsville Member''' is reddish brown, bentonitic mudstone up to {{convert|26|meter|feet|abbr=off}} thick. It is named for the nearby village of Youngsville.{{sfn|Lucas|Zeigler|Heckert|Hunt|2005}}
==Fossils== [[Tetrapod]] fossils have been identified in the type section of the Youngsville Member. These include [[coprolite]]s and indeterminate [[metoposaurid]] and [[phytosaur]] remains, including a paramedian [[scute]] that may be the [[aetosaur]] ''[[Longosuchus]]'' or ''[[Desmatosuchus]]''.{{sfn|Lucas|Zeigler|Heckert|Hunt|2005}}
==Footnotes== {{reflist}}
==References== *{{Cite journal |last=Cather |first=Steven M. |last2=Zeigler |first2=Kate E. |last3=Mack |first3=Greg H. |last4=Kelley |first4=Shari A. |date=2013-01-01 |title=Toward standardization of Phanerozoic stratigraphic nomenclature in New Mexico |url=https://doi.org/10.2113/gsrocky.48.2.101 |journal=Rocky Mountain Geology |volume=48 |issue=2 |pages=101–124 |doi=10.2113/gsrocky.48.2.101 |issn=1555-7332|url-access=subscription }} * {{cite journal |last1=Lucas |first1=Spencer G. |last2=Zeigler |first2=Kate E. |last3=Heckert |first3=Andrew B. |last4=Hunt |first4=Adrian P. |title=Review of Upper Triassic stratigraphy and biostratigraphy in the Chama Basin, northern New Mexico |journal=New Mexico Geological Society Field Conference Series |date=2005 |volume=56 |pages=170–181 |url=https://nmgs.nmt.edu/publications/guidebooks/downloads/56/56_p0170_p0181.pdf |accessdate=29 April 2020}} * {{cite journal |last1=Lucas |first1=S.G. |last2=Hunt |first2=A.P. |year=1992 |title=Triassic stratigraphy and paleontology, Chama Basin and adjacent areas, north-central New Mexico |journal=New Mexico Geological Society Field Conference Series |volume=43 |pages=151–167 |url=https://nmgs.nmt.edu/publications/guidebooks/downloads/43/43_p0151_p0172.pdf |accessdate=20 May 2020}} * {{cite journal|title= Stratigraphy and Origin of the Chinle Formation and Related Upper Triassic Strata in the Colorado Plateau Region|date=1972|first1= John Harris |last1=Stewart|first2=Forrest Graham |last2=Poole|first3=Richard Farifield |last3=Wilson|first4= R.A. |last4=Cadigan|first5=William |last5=Thordarson|first6= H.F. |last6=Albee|doi=10.3133/pp690 |journal=U.S. Geological Survey Professional Paper|doi-access=free}} * {{cite journal|title= Geology of the Nacimiento Mountains, San Pedro Mountain, and adjacent plateaus in parts of Sandoval and Rio Arriba Counties, New Mexico|date=1946|last1= Wood |first1=G.H.|last2= Northrop |first2=S.A.|url= https://ngmdb.usgs.gov/Prodesc/proddesc_5417.htm|access-date= 11 November 2019|url-status= live|journal=Oil and Gas Investigations Map |volume=OM-57|archive-url=https://web.archive.org/web/20211112180753/https://ngmdb.usgs.gov/Prodesc/proddesc_5417.htm|archive-date=12 November 2021}}
[[Category:Triassic formations of New Mexico]] [[Category:Shale formations of the United States]]