Mata Amarilla Formation

Last updated
Mata Amarilla Formation
Stratigraphic range: Mid Cenomanian
96.94–95.52  Ma
O
S
D
C
P
T
J
K
Pg
N
Austral Basin - Geologic Map - Mata Amarilla, La Anita & Piedra Clavada Formations, Argentina.jpg
Map of Mata Amarilla and surrounding formations
Type Geological Formation
Sub-unitsUpper, Middle and Lower members
Underlies Alta Vista Formation
Overlies Piedra Clavada Formation
Lithology
Primary Siltstone, claystone
Other Sandstone, tuff, paleosols
Location
Coordinates 49°30′S71°30′W / 49.5°S 71.5°W / -49.5; -71.5
Approximate paleocoordinates 56°30′S48°48′W / 56.5°S 48.8°W / -56.5; -48.8
Region Santa Cruz Province
CountryArgentina
Extent Austral Basin
Relief Map of Argentina.jpg
Lightgreen pog.svg
Mata Amarilla Formation (Argentina)
Stratigraphic column Mata Amarilla Formation - stratigraphic column.jpg
Stratigraphic column

The Mata Amarilla Formation is a fossiliferous formation of the Austral Basin in southern Patagonia, Argentina. The formation consists of sediments deposited during the Middle Cenomanian, dated to 96.94 to 95.52 Ma. The middle section of the formation was previously considered to be the Pari Aike Formation.

Contents

The Mata Amarilla Formation has provided many fossil vertebrates, among which dinosaurs, fish and turtles, as well as fossil insects, flora and molluscs.

Age

Paleogeography of the Late Cretaceous (90 Ma) with known distribution of Arcellites disciformis indicated 90 Ma - Late Cretaceous paleogeography with known distribution of Arcellites disciformis indicated.jpg
Paleogeography of the Late Cretaceous (90 Ma) with known distribution of Arcellites disciformis indicated

The middle section of the Mata Amarilla Formation has widely been regarded as Maastrichtian in age, but recent dating of a lava tuff layer shows that it dates back to 96.2 ± 0.7 Ma, during the Cenomanian. [1]

Description

The Austral (or Magallanes) Basin, is located on the southwestern end of the South American Plate and it is bordered to the south by the Scotia Plate covering an area of approximately 230.000 square kilometres (88.803 sq mi). In the studied area, the Austral Basin underwent three main tectonic stages: (i) a rift stage; (ii) a thermal subsidence stage; and (iii) a foreland stage.

The rifting stage is related to the break-up of Gondwana, grabens and half-grabens were formed and filled with volcaniclastic and volcanic rocks intercalated with epiclastic sediments of the El Quemado and Tobífera Formations. [2]

Subsequently, the thermal subsidence stage resulted in the deposition of the transgressive quartzose sandstone of the Springhill Formation, and the black mudstone and marl of the Río Mayer Formation. Towards the end of this stage, the Piedra Clavada Formation was deposited, representing a large passive-margin delta system.

The foreland stage, in response to the regional change from extensive to compressive regime, resulted in the deposition of the continental Mata Amarilla Formation. This unit is mainly composed of grey and blackish siltstone and claystone, alternating with whitish and yellowish-grey fine to medium grained sandstone. Varela (2014) recognized three informal sections (lower, middle, and upper) on the bases of sedimentological and sequence stratigraphic analysis. The lower section consists of fine-grained intervals with paleosols interbedded with laminated shale and coquina, representing coastal plain and lagoon paleoenvironments.

The middle section comprises sandstone and siltstone representing meandering fluvial channels and crevasse splay deposits, intercalated with fine-grained floodplains and subordinate lacustrine deposits. The upper section is dominated by fine-grained deposits, related to distal fluvial channels.

Paleosol features and paleosol-derived climatic proxies suggest a subtropical temperate-warm, at 12 ± 2.1 °C (53.6 ± 3.8 °F) and humid, with 1,404 ± 108 millimetres (55.3 ± 4.3 in)/yr, climate with marked rainfall seasonality during the deposition of this unit (Varela et al. 2012b; 2018), in accordance with previous paleobotanical interpretations. [3]

Fossil content

Dinosaurs

Dinosaurs
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Clasmodosaurus C. spatulaMiddle Section
Loncosaurus L. argentinusMiddle Section

Related Research Articles

<span class="mw-page-title-main">Alfisol</span> Soil type

Alfisols are a soil order in USDA soil taxonomy. Alfisols form in semi-arid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to aluminium (Al) and iron (Fe). Because of their productivity and abundance, Alfisols represent one of the more important soil orders for food and fiber production. They are widely used both in agriculture and forestry, and are generally easier to keep fertile than other humid-climate soils, though those in Australia and Africa are still very deficient in nitrogen and available phosphorus. Those in monsoonal tropical regions, however, have a tendency to acidify when heavily cultivated, especially when nitrogenous fertilizers are used.

<span class="mw-page-title-main">Neuquén Group</span> Group of geologic formations in Argentina

The Neuquén Group is a group of geologic formations found in Argentina. Rocks in the Neuquén Group fall within the Cenomanian to early Campanian stages of the Late Cretaceous Period. It overlies the older Lohan Cura Formation and is itself overlain by the younger Allen Formation of the Malargüe Group, separated from both by unconformities, dated to 98 and 79 Ma respectively.

<span class="mw-page-title-main">Candeleros Formation</span> Geologic formation in Argentina

The Candeleros Formation is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formation in the Neuquén Group and belongs to the Rio Limay Subgroup. Formerly that subgroup was treated as a formation, and the Candeleros Formation was known as the Candeleros Member.

The Huincul Formation is a geologic formation of Late Cretaceous age of the Neuquén Basin that outcrops in the Mendoza, Río Negro and Neuquén Provinces of northern Patagonia, Argentina. It is the second formation in the Río Limay Subgroup, the oldest subgroup within the Neuquén Group. Formerly that subgroup was treated as a formation, and the Huincul Formation was known as the Huincul Member.

The Lisandro Formation, alternatively known as the Cerro Lisandro Formation, is a Late Cretaceous geologic formation with outcrops in the Neuquén, Río Negro and Mendoza Provinces of Argentina. It is the youngest formation within the Río Limay Subgroup, the lowest section of the Neuquén Group. Formerly that subgroup was treated as a formation, and the Lisandro Formation was known as the (Cerro) Lisandro Member.

<span class="mw-page-title-main">Bajo de la Carpa Formation</span> Geological formation in Argentina

The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that crops out in northern Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the oldest of two formations belonging to the Río Colorado Subgroup within the Neuquén Group. Formerly, that subgroup was treated as a formation, and the Bajo de la Carpa Formation was known as the Bajo de la Carpa Member.

<i>Puertasaurus</i> Extinct genus of dinosaurs

Puertasaurus is a genus of sauropod dinosaur that lived in South America during the Late Cretaceous Period. It is known from a single specimen recovered from sedimentary rocks of the Cerro Fortaleza Formation in southwestern Patagonia, Argentina, which probably is Campanian or Maastrichtian in age. The only species is Puertasaurus reuili. Described by the paleontologist Fernando Novas and colleagues in 2005, it was named in honor of Pablo Puerta and Santiago Reuil, who discovered and prepared the specimen. It consists of four well-preserved vertebrae, including one cervical, one dorsal, and two caudal vertebrae. Puertasaurus is a member of Titanosauria, the dominant group of sauropods during the Cretaceous.

Ausktribosphenidae is an extinct family of australosphenidan mammals from the Early Cretaceous of Australia and mid Cretaceous of South America.

<i>Orkoraptor</i> Extinct genus of dinosaurs

Orkoraptor is a genus of medium-sized megaraptoran theropod dinosaur from the late Cretaceous Period of Argentina. It is known from incomplete fossil remains including parts of the skull, teeth, tail vertebrae, and a partial tibia. The specialized teeth resemble those of some maniraptoriform theropods, namely the deinonychosaurs and compsognathids. This and other anatomical features led the authors who described it to suggest that it was a maniraptoran coelurosaur. However, subsequent studies found it to be a megaraptoran. Found in the Cerro Fortaleza Formation of Southern Patagonia, it is one of the southernmost carnivorous dinosaurs known from South America.

The Bajo Barreal Formation is a geological formation in the Golfo San Jorge Basin of Chubut and Santa Cruz, Argentina whose strata date back to the Middle Cenomanian to Late Turonian. The formation was first described by Teruggi & Rossetto in 1963. The sandstones, claystones, mudstones, conglomerates and tuff were deposited in a fluvial environment. The upper part of formation is laterally equivalent to the Yacimiento El Trébol and Meseta Espinosa Formation and the lower part to the Laguna Palacios, Cañadón Seco and Comodoro Rivadavia Formations. The Bajo Barreal Formation is a reservoir rock in the Golfo San Jorge Basin.

<i>Austrocheirus</i> Genus of reptiles (fossil)

Austrocheirus is an extinct genus of theropod dinosaur that lived during the Late Cretaceous period. It was named and described by Martin Ezcurra, Federico Agnolin and Fernando Novas in 2010. It contains the type species Austrocheirus isasii. The generic name means "southern hand". The specific epithet honours discoverer and preparator Marcelo Pablo Isasi.

The Cerro Fortaleza Formation, in older literature described as Pari Aike Formation, is a Late Cretaceous geologic formation of Campanian to Maastrichtian age of the Austral Basin in southern Patagonia, Argentina.

<span class="mw-page-title-main">Malargüe Group</span> Group of geologic formations in Argentina

The Malargüe Group is a group of geologic formations of the Neuquén Basin of the Mendoza, Neuquén, Río Negro and La Pampa Provinces in northern Patagonia, Argentina. The formations of the Malargüe Group range in age between the middle Campanian to Deseadan, an Oligocene age of the SALMA classification, straddling the Cretaceous–Paleogene boundary, about 79 million to 30 million years in age. The group overlies the older Neuquén Group, separated by an unconformity dated to 79 Ma. The rocks of the Malargüe Group comprise both marine and continental deposits which are over 400 m (1312 ft) thick in total.

<i>Leinkupal</i> Extinct genus of reptiles

Leinkupal is a genus of diplodocine sauropod known from the Early Cretaceous of the Bajada Colorada Formation, southeastern Neuquén Basin in the Neuquén Province of Argentina. It contains a single species, Leinkupal laticauda.

Tralkasaurus is a genus of abelisaurid dinosaur from the Huincul Formation from Río Negro Province in Argentina. The type and only species is Tralkasaurus cuyi, named in 2020 by Mauricio Cerroni and colleagues based on an incomplete skeleton. A medium-sized abelisaurid, Tralkasaurus exhibits a conflicting blend of characteristics found among the early-diverging abelisauroids with others that characterize the highly specialized clade Brachyrostra, and thus its position within the clade is poorly-resolved.

<span class="mw-page-title-main">Lefipán Formation</span> Geologic formation in Argentina

The Lefipán Formation is a Maastrichtian to Danian, straddling the Cretaceous-Paleogene boundary, geologic formation of the Cañadón Asfalto Basin in Chubut Province, Patagonia, Argentina. The up to 380 metres (1,250 ft) thick stratigraphic unit comprises mudstones, sandstones, siltstones and conglomerates, sourced from the North Patagonian Massif and deposited in a deltaic to shallow marine environment with a strong tidal influence. The basin that in those times was connected to the widening South Atlantic Ocean with a seaway connection to the Austral Basin and possibly with the Pacific Ocean.

Kaikaifilusaurus is an extinct genus of rhynchocephalians in the family Sphenodontidae from the Late Cretaceous of South America. Fossils of the genus were found in Cenomanian sediments of the Candeleros Formation and Turonian layers of the Huincul Formation, both of the Neuquén Basin and the Albian strata of the Cerro Barcino Formation in the Cañadón Asfalto Basin, all in Patagonia, Argentina. The genus contains two species, K. minimus and the type species K. calvoi.

<span class="mw-page-title-main">Dorotea Formation</span> Geological formation in the Río de Las Chinas Valley, Magallanes Basin, Chile

The Dorotea Formation is a geological formation in the Río de Las Chinas Valley of the Magallanes Basin in Patagonian Chile whose strata date back to the Campanian to Maastrichtian of the Late Cretaceous.

Perforissidae is an extinct family of planthoppers. They are considered to belong to the group of "Cixiidae-like" planthoppers. Species are known from the Early to Late Cretaceous of Eurasia, North America and South America. The family was named by Shcherbakov in 2007

<span class="mw-page-title-main">Salamanca Formation</span> Geologic formation in Chubut Province, Argentina

The Salamanca Formation is a geologic formation in the Golfo San Jorge Basin of central Patagonia that yields well-preserved, well-dated fossils from the early Paleocene. Studies of these fossils are providing new data on plant and animal diversity following the end-Cretaceous extinction event.

References

  1. Varela et al., 2012
  2. Santamarina et al., 2018, p.608
  3. Santamarina et al., 2018, p.609
  4. 1 2 3 4 Martin, T.; Goin, F. J.; Schultz, J. A.; Gelfo, J. N. (2021). "Early Late Cretaceous mammals from southern Patagonia (Santa Cruz province, Argentina)". Cretaceous Research. 133: 105127. doi:10.1016/j.cretres.2021.105127. S2CID   245549530.
  5. Begat, A.; Kriwet, J.; Gelfo, J. N.; Gouiric Cavalli, S.; Schultz, J. A.; Martin, T. (2023). "The first southern hemisphere occurrence of the extinct Cretaceous sclerorhynchoid sawfish Ptychotrygon (Chondrichthyes, Batoidea), with a review of Ptychotrygon taxonomy". Journal of Vertebrate Paleontology. 42 (2). e2162411. doi: 10.1080/02724634.2022.2162411 . PMC   7614936 . PMID   37564697. S2CID   256750575.
  6. Cerro Waring at Fossilworks.org
  7. Santamarina et al., 2018, p.610

Bibliography

Further reading