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.

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. 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.

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. The thickness of the formation ranges from 100 metres (330ft) in the Sierra Baguales in the north to 350 metres (1,150ft) in the eponymous Sierra Dorotea in the south.

Fossil content

The following fossils were reported from the formation:

Amphibians

Amphibians of Dorotea Formation
TaxaSpeciesMaterialNotesImages
AnuraIndeterminateA frog

Reptiles

Reptiles of Dorotea Formation
TaxaSpeciesLocalityMaterialNotesImages
AristonectinaeIndeterminate
AristonectesA. sp.
Yaminuechelyscf. Yaminuechelys sp.
PanchelidaeIndeterminateSaurópodo sector (Section SP-17).Distal fragment of right humerus and distal end of right femur.
ElasmosauridaeIndeterminate

Dinosaurs

Ornithischians

Ornithischians of Dorotea Formation
TaxaSpeciesLocalityMaterialNotesImages
GonkokenG. nanoiLoma KokenSeveral incomplete specimens belonging to individuals of different agesA hadrosauroid
OrnithischiaIndeterminate
StegourosS. elengassenCPAP-3165 (holotype), a holotype consists of a relatively complete skeleton with a skull and lower jaws.A parankylosaur

Saurischians

Saurischians of Dorotea Formation
TaxaSpeciesMaterialNotesImages
EnantiornithesIndeterminate
MegaraptoridaeIndeterminate
OrnithuraeIndeterminate
SauropodaIndeterminate
UnenlagiinaeIndeterminate
TheropodaIndeterminate

Mammals

Mammals of Dorotea Formation
TaxaSpeciesLocalityMaterialNotesImages
MagallanodonM. baikashkenkeMammal quarry from the Río de Las Chinas valleyA first lower left molariformA gondwanathere
OrretheriumO. tzenMammal quarry from the Río de Las Chinas valleyA fragmented lower jaw.A mesungulatid mammal
MammaliaIndeterminate
YeutheriumY. pressor'Black Bone' LocalityA left maxilla fragment with M1, roots of M2 and mesial roots of M3.A subantarctic reigitheriidae mammal

Fish

Fish of Dorotea Formation
TaxaSpeciesMaterialNotesImages
IschyrhizaI. chilensis
CarchariasC. sp.
SerratolamnaIndeterminate

Invertebrates

Invertebrates of Dorotea Formation
TaxaSpeciesLocalityMaterialNotesImages
DorotheusDorotheus guidensis
PterotrigoniaP. cazadoriana
GunnaritesG. sp.
PachydiscusP. aff. gollevilensis

See also

Bibliography

  • Alarcón-Muñoz, Jhonatan; Soto-Acuña, Sergio; Manríquez, Leslie M.E.; Fernández, Roy A.; Bajor, Dániel; Guevara, Juan Pablo; Suazo Lara, Felipe; Leppe, Marcelo A.; Vargas, Alexander O. (October 2020). . Journal of South American Earth Sciences. 102 102652. Bibcode:. doi:.
  • Goin, Francisco J.; et, al (2020), (PDF), Boletín del Museo Nacional de Historia Natural, Chile, 69 (1): 5–31, doi:
  • Goin, Francisco J.; Martinelli, Agustín G.; Soto-Acuña, Sergio; Vieytes, Emma C.; Manríquez, Leslie M. E.; Fernández, Roy A.; Pino, Juan Pablo; Trevisan, Cristine; Kaluza, Jonatan; Reguero, Marcelo A.; Leppe, Marcelo; Ortiz, Héctor; Rubilar-Rogers, David; Vargas, Alexander O. (28 June 2020). "Primer mamífero Mesozoico de Chile: el registro más austral de un gondwanaterio del Cretácico tardío". Boletín Museo Nacional de Historia Natural. 69 (1): 5–31. doi:.
  • Otero, Rodrigo A.; Soto-Acuña, Sergio; Salazar S., Christian; Oyarzún, José Luis (29 May 2015). . Andean Geology. 42 (2). Bibcode:. doi:.
  • Otero, Rodrigo A; Suárez, Mario E; Le Roux, Jacobus P (July 2009). "First record of Elasmosaurid Plesiosaurs (Sauropterygia: Plesiosauria) in upper levels of the Dorotea Formation, Late Cretaceous (Maastrichtian), Puerto Natales, Chilean Patagonia". Andean Geology. 36 (2). Bibcode:. doi:.
  • Kuschel, G (1959), "Un curculionido del Cretácico Superior - primer insecto fósil de Chile", Investigaciones Zoológicas Chilenas, 5: 49–54