Lagarcito Formation
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The Lagarcito Formation is an
Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...
geologic formation in
Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...
.
Pterosaur Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earli ...
fossils have been recovered from the formation. The formation overlies the La Cruz Formation and is overlain by the San Roque Formation. The
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
s and
mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...
s of the formation were deposited in a
fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...
and mostly
lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...
environment.Gardini et al., 2009, p.554 The fossil association and the geological evidence indicate that the Lagarcito Formation represents a perennial shallow lake situated in an
alluvial plain An alluvial plain is a plain (an essentially flat landform) created by the deposition of sediment over a long period by one or more rivers coming from highland regions, from which alluvial soil forms. A ''floodplain'' is part of the process, bei ...
where detrital sedimentation and semiarid climatic conditions predominated.


Fossil content

The following fossils have been found in the Lagarcito Formation:Loma del Pterodaustro
at
Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...
.org * '' Austrolepidotus cuyanus'' * '' Lepidotes pusillus'' * '' Neosemionotus puntanus'' * ''
Pterodaustro guinazui ''Pterodaustro'' (from Greek , and Latin , ) is a genus of ctenochasmatid pterodactyloid pterosaur from South America. Its fossil remains dated back to the Early Cretaceous period, about 105 million years ago. Discovery and naming The firs ...
'' * '' Treptichnus pollardi'' * '' Zurupleuropholis quijadensis'' * '' Cyzicus aff. codoensis'' * '' Darwinula sp.'' * '' Copytus sp.'' * '' Bisulcocypris sp.'' * '' Candonopsis sp.'' * Anura indet. * Magnoliophyta indet. * Trichoptera indet.


See also

*
List of pterosaur-bearing stratigraphic units A list is a set of discrete items of information collected and set forth in some format for utility, entertainment, or other purposes. A list may be memorialized in any number of ways, including existing only in the mind of the list-maker, bu ...


References


Bibliography

* {{citation , last=Gardini , first=Carlos , last2=Rivarola , first2=David , last3=Agüera , first3=Maximiliano , last4=Candela , first4=Gerónimo , year=2009 , title=Estructura de la región Sierra de Guayaguas-Marayes, Provincias de San Juan y San Luis , url=http://www.scielo.org.ar/pdf/raga/v65n3/v65n3a12.pdf , journal=
Revista de la Asociación Geológica Argentina The ''Revista de la Asociación Geológica Argentina'' is an open access peer-reviewed scientific journal published by the Asociación Geológica Argentina. The journal is released under a CC-BY-NC 2.5 license.Geologic formations of Argentina Cretaceous Argentina Albian Stage Sandstone formations Mudstone formations of Argentina Fluvial deposits Lacustrine deposits Ichnofossiliferous formations Fossiliferous stratigraphic units of South America Paleontology in Argentina Geology of San Luis Province