Dorotea Formation

Dorotea Formation
Stratigraphic range: Late Campanian-Maastrichtian
~
TypeGeological formation
UnderliesMan Aike Formation
OverliesTres Pasos Formation
Thickness100–350 m (330–1,150 ft)
Lithology
PrimarySandstone, claystone
OtherConglomerate
Location
Coordinates50°42′S 72°30′W / 50.7°S 72.5°W / -50.7; -72.5
Approximate paleocoordinates52°54′S 60°30′W / 52.9°S 60.5°W / -52.9; -60.5
RegionMagallanes Region
CountryChile
ExtentRío de Las Chinas Valley, Magallanes Basin
Type section
Named forSierra Dorotea
Named byKatz
Year defined1963
Dorotea Formation is located in Chile
Dorotea Formation
Dorotea Formation (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.[1]

Description

The Dorotea Formation was first described by Katz in 1963. The formation comprises sandstones with frequent conglomerate lenses, concretionary levels and claystones. The Dorotea Formation includes calcareous sandstones with abundant marine invertebrate and fragmentary vertebrate fossils. Hervé et al. (2004) obtained a maximum radiometric age of 67.4 ± 1.5 Ma from detrital zircons contained in sandstones of the Dorotea Formation.[2] Near the top of the formation is an iridium anomaly, correlated with the Cretaceous–Paleogene boundary; this is the southernmost K–Pg boundary site known from South America.[3]

The mudstones and sandstones of the formation were deposited in a fluvial environment. The formation conformably overlies the Tres Pasos Formation and is unconformably overlain by the Lutetian to Bartonian Man Aike Formation.[4] The thickness of the formation ranges from 100 metres (330 ft) in the Sierra Baguales in the north to 350 metres (1,150 ft) in the eponymous Sierra Dorotea in the south.[5]

Fossil content

The following fossils were reported from the formation:[6]

Amphibians

Amphibians of Dorotea Formation
Taxa Species Material Notes Images
Anura[7] Indeterminate A frog

Reptiles

Reptiles of Dorotea Formation
Taxa Species Locality Material Notes Images
Aristonectinae[8] Indeterminate
Aristonectes A. sp.[8]
Yaminuechelys cf. Yaminuechelys sp.[7]
Panchelidae[7] Indeterminate Saurópodo sector (Section SP-17). Distal fragment of right humerus and distal end of right femur.
Elasmosauridae Indeterminate

Dinosaurs

Ornithischians

Ornithischians of Dorotea Formation
Taxa Species Locality Material Notes Images
Gonkoken[9] G. nanoi Loma Koken Several incomplete specimens belonging to individuals of different ages A hadrosauroid
Ornithischia[7] Indeterminate
Stegouros S. elengassen CPAP-3165 (holotype), a holotype consists of a relatively complete skeleton with a skull and lower jaws. A parankylosaur

Saurischians

Saurischians of Dorotea Formation
Taxa Species Material Notes Images
Enantiornithes[10] Indeterminate
Megaraptoridae[10] Indeterminate
Ornithurae[10] Indeterminate
Sauropoda[7] Indeterminate
Unenlagiinae[10] Indeterminate
Theropoda[7][10] Indeterminate

Mammals

Mammals of Dorotea Formation
Taxa Species Locality Material Notes Images
Magallanodon[11] M. baikashkenke[11] Mammal quarry from the Río de Las Chinas valley A first lower left molariform A gondwanathere
Orretherium O. tzen[12] Mammal quarry from the Río de Las Chinas valley A fragmented lower jaw. A mesungulatid mammal
Mammalia[7] Indeterminate
Yeutherium Y. pressor[13] 'Black Bone' Locality A left maxilla fragment with M1, roots of M2 and mesial roots of M3. A subantarctic reigitheriidae mammal

Fish

Fish of Dorotea Formation
Taxa Species Material Notes Images
Ischyrhiza I. chilensis[5]
Carcharias C. sp.[5]
Serratolamna Indeterminate[5]

Invertebrates

Invertebrates of Dorotea Formation
Taxa Species Locality Material Notes Images
Dorotheus Dorotheus guidensis[14]
Pterotrigonia P. cazadoriana[2]
Gunnarites G. sp.[2]
Pachydiscus P. aff. gollevilensis[2]

See also

References

  1. ↑ Dorotea Formation at Fossilworks.org
  2. 1 2 3 4 Otero et al., 2009
  3. ↑ Manríquez, Leslie M. E.; Krahl, Guilherme; Carvalho, Marcelo A.; Lavina, Ernesto L. C.; Santiago, Gustavo; Bom, Marlone H. H.; Fauth, Gerson; Leppe, Marcelo (October 2024). "The K/Pg event at high southern latitudes: New evidence from continental deposits in the Magallanes/Austral Basin, Patagonia, South America". Cretaceous Research. 162 105931. Bibcode:2024CrRes.16205931M. doi:10.1016/j.cretres.2024.105931.
  4. ↑ Goin et al., 2020, p.9
  5. 1 2 3 4 Otero et al., 2015, p.240
  6. ↑ Río de las Chinas Valley at Fossilworks.org
  7. 1 2 3 4 5 6 7 Alarcón Muñoz et al., 2020
  8. 1 2 Otero et al., 2015
  9. ↑ Alarcón-Muñoz, Jhonatan; Vargas, Alexander O.; Püschel, Hans P.; Soto-Acuña, Sergio; Manríquez, Leslie; Leppe, Marcelo; Kaluza, Jonatan; Milla, Verónica; Gutstein, Carolina S.; Palma-Liberona, José; Stinnesbeck, Wolfgang; Frey, Eberhard; Pino, Juan Pablo; Bajor, Dániel; Núñez, Elaine (2023-06-16). "Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile". Science Advances. 9 (24) eadg2456. Bibcode:2023SciA....9G2456A. doi:10.1126/sciadv.adg2456. ISSN 2375-2548. PMC 10275600. PMID 37327335.
  10. 1 2 3 4 5 Davis, Sarah N.; Soto-Acuña, Sergio; Fernández, Roy A.; Amudeo, Jared; Leppe, Marcelo A.; Rubilar-Rogers, David; Vargas, Alexander O.; Clarke, Julia A. (December 2022). "New records of Theropoda from a Late Cretaceous (Campanian-Maastrichtian) locality in the Magallanes-Austral Basin, Patagonia, and insights into end Cretaceous theropod diversity". Journal of South American Earth Sciences. 122 104163. doi:10.1016/j.jsames.2022.104163. S2CID 254850180.
  11. 1 2 Goin et al., 2020
  12. ↑ Martinelli, A. G.; Soto-Acuña, S.; Goin, F. J.; Kaluza, J.; Bostelmann, J. E.; Fonseca, P. H. M. F.; Reguero, M. A.; Leppe, M.; Vargas, A. O. (2021). "New cladotherian mammal from southern Chile and the evolution of mesungulatid meridiolestidans at the dusk of the Mesozoic era". Scientific Reports. 11 (7594): 7594. Bibcode:2021NatSR..11.7594M. doi:10.1038/s41598-021-87245-4. PMC 8027844. PMID 33828193.
  13. ↑ Püschel, Hans P.; Martinelli, Agustin G.; Soto-Acuña, Sergio; Ortiz, Héctor; Leppe, Marcelo; Vargas, Alexander O. (August 2025). "A subantarctic reigitheriid and the evolution of crushing teeth in these enigmatic Mesozoic mammals". Proceedings of the Royal Society B: Biological Sciences. 292 (2052) 20251056. doi:10.1098/rspb.2025.1056. PMID 40763811.
  14. ↑ Kuschel, 1959

Bibliography

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