Dorotea Formation Explained

Dorotea Formation
Type:Geological formation
Period:Maastrichtian
Age:Late Campanian-Maastrichtian
~
Prilithology:Sandstone, claystone
Otherlithology:Conglomerate
Namedfor:Sierra Dorotea
Namedby:Katz
Year Ts:1963
Region:Magallanes Region
Coordinates:-50.7°N -72.5°W
Paleocoordinates:-52.9°N -60.5°W
Underlies:Man Aike Formation
Overlies:Tres Pasos Formation
Thickness:100-
Extent:Río de Las Chinas Valley, Magallanes Basin

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.

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.[2] The thickness of the formation ranges from 100m (300feet) in the Sierra Baguales in the north to 350m (1,150feet) in the eponymous Sierra Dorotea in the south.[3]

Fossil content

The following fossils were reported from the formation:[4]

Reptiles

Reptiles of Dorotea Formation
TaxaSpeciesMaterialNotesImages
Aristonectinae[5] Indeterminate
AristonectesAristonectes sp.
Yaminuechelyscf. Yaminuechelys sp.[6]
PanchelidaeIndeterminate
ElasmosauridaeIndeterminate

Dinosaurs

Dinosaurs of Dorotea Formation
TaxaSpeciesMaterialNotesImages
Enantiornithes[7] Indeterminate
Gonkoken[8] G. nanoiSeveral incomplete specimens belonging to individuals of different agesA hadrosauroid
MegaraptoridaeIndeterminate
OrnithischiaIndeterminate
OrnithuraeIndeterminate
SauropodaIndeterminate
StegourosS. elengassenCPAP-3165 (holotype), a holotype consists of a relatively complete skeleton with a skull and lower jaws.A parankylosaur
UnenlagiinaeIndeterminate
TheropodaIndeterminate

Mammals

Mammals of Dorotea Formation
TaxaSpeciesMaterialNotesImages
Magallanodon[9] M. baikashkenke[10] A gondwanathere
OrretheriumO. tzen[11] A mesungulatid mammal
MammaliaIndeterminate

Fish

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

Invertebrates

Invertebrates of Dorotea Formation
TaxaSpeciesMaterialNotesImages
DorotheusDorotheus guidensis[12]
PterotrigoniaP. cazadoriana[13]
GunnaritesG. sp.
PachydiscusP. aff. gollevilensis

See also

References

Bibliography

Notes and References

  1. http://www.fossilworks.org/cgi-bin/bridge.pl?action=displayStrata&geological_group=&formation=Dorotea&group_formation_member=Dorotea Dorotea Formation
  2. Goin et al., 2020, p.9
  3. Otero et al., 2015, p.240
  4. http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&collection_no=210130 Río de las Chinas Valley
  5. Otero et al., 2015
  6. Alarcón Muñoz et al., 2020
  7. 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 . en . 104163 . 10.1016/j.jsames.2022.104163. 254850180 . free .
  8. 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 . en . 9 . 24 . eadg2456 . 10.1126/sciadv.adg2456 . 37327335 . 10275600 . 2023SciA....9G2456A . 2375-2548.
  9. Goin et al., 2020
  10. Goin et al., 2020
  11. 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. 10.1038/s41598-021-87245-4. free. 7594. 7594 . 33828193 . 8027844 . 2021NatSR..11.7594M .
  12. Kuschel, 1959
  13. Otero et al., 2009