The Malargüe Group is a

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

s of the

Neuquén Basin Neuquén Basin () is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The basin bounds to the wes ...

of the Mendoza,

Neuquén Neuquén (; ) is the capital city of the Argentine province of Neuquén and of the Confluencia Department, located in the east of the province. It occupies a strip of land west of the confluence of the Limay and Neuquén rivers which form t ...

, Río Negro and

La Pampa Province La Pampa () is a sparsely populated province of Argentina, located in the Pampas in the center of the country. Neighboring provinces are from the north clockwise San Luis, Córdoba, Buenos Aires, Río Negro, Neuquén and Mendoza. History In ...

s in northern

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

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 ...

. The formations of the Malargüe Group range in age between the middle

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

Deseadan The Deseadan () age is a period of geologic time (29.0–21.0 Ma) within the Oligocene epoch of the Paleogene to the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It follows the Tingu ...

, an

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

age of the SALMA classification, straddling the

Cretaceous–Paleogene boundary The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary, is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end o ...

, about 79 million to 30 million years in age. The group overlies the older Neuquén Group, separated by an unconformity dated to 79 Ma.Leanza et al., 2004, p.63 The rocks of the Malargüe Group comprise both marine and continental deposits which are over 400 m (1312 ft) thick in total.

Subdivision

The Malargüe Group is subdivided into: *

Agua de la Piedra Formation The Agua de la Piedra Formation (FAP, Spanish names include ''Estratos de Agua de la Piedra'' and ''Complejo Volcano-sedimentario del Terciario inferior'')Combina et al., 1994, p.418 is a Late Oligocene (Deseadan in the South American land mammal ...

(

) - white-grayish

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

s and tobaceous

paleosol In Earth science, geoscience, paleosol (''palaeosol'' in Great Britain and Australia) is an ancient soil that formed in the past. The definition of the term in geology and paleontology is slightly different from its use in soil science. In geo ...

sAgua de la Piedra Formation
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 * Roca Formation (Maastrichtian to Danian) - coastal mudstones and sandstonesRoca Formation
at

.org * Jagüel Formation (middle Maastrichtian to Danian) - shallow marine

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, ...

sJagüel Formation
at

.org * Loncoche Formation (late Campanian to early Maastrichtian) - terrestrial conglomerates and

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, delta plain sandstones and

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

sLoncoche Formation
at

.org *

Allen Formation The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous (middle Campanian to early Maastrichtian.Salgado et al., 2007 Dinosaur remains are among the fossils that have been recovered from the forma ...

(middle Campanian to early

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

) - eolian

s and fluvio-

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 ...

mudstones and

Fossil content

Fossils of

dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

plesiosaurs The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

s ('' Euclastes'',''Euclastes''
at

.org '' Mendozachelys wichmanni''),De la Fuente et al., 2017 '' Paleoanculosa sp.'',Previtera & González Riga, 2008

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

,Gónzalez Riga, 1999

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s ('' cf. Andrewsornis sp.'') and

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

have been recovered from the strata that make up the Malargüe Group.Weishampel et al., 2004 ;Mammals of the Agua de la Piedra Formation '' Archaeohyrax suniensis'', '' Argyrohyrax proavus'', '' Asmodeus petrasnerus'', '' Fieratherium sorex'', '' Gualta cuyana'', '' Hegetotheriopsis sulcatus'', '' Mendozahippus fierensis'', '' Meteutatus aff. lagenaformis'', '' Proborhyaena gigantea'', '' Prohegetotherium malalhuense'', '' P. schiaffinoi'', '' P. cf. sculptum'', '' Propachyrucos cf. smithwoodwardi'', '' ?Prozaedyus aff. impressus'', '' Pyrotherium romeroi'', '' Stenotatus aff. ornatus'', '' Trachytherus cf. spegazzinianus'', '' cf. Archaeotypotherium sp.'', '' Pharsophorus sp.'', '' Proadinotherium sp.'', '' Progaleopithecus sp.'', '' cf. Prosotherium sp.'', Acaremyidae indet., Glyptodontidae indet., Interatheriidae indet., Litopterna indet., ?Megalonychidae indet., Notohippidae indet., Toxodontidae indet.Quebrada Fiera
at

.orgCerdeño & Reguero, 2015Seoane & Cerdeño, 2014Cerdeño & Vera, 2014

References

Bibliography

;Cretaceous * * * * * ;Paleogene * * * * * {{DEFAULTSORT:Malargue Group Geologic formations of Argentina Upper Cretaceous Series of South America Paleocene Series of South America Oligocene Series of South America Sandstone groups Mudstone groups Conglomerate groups Limestone groups Tuff groups Fluvial deposits Deltaic deposits Lacustrine deposits Aeolian deposits Shallow marine deposits Geology of La Pampa Province Geology of Mendoza Province Geology of Neuquén Province Geology of Río Negro Province

Subdivision

Fossil content

See also

References

Bibliography