Hornitos Formation

Last updated
Hornitos Formation
Stratigraphic range: Late Cretaceous, Campanian–Maastrichtian
Type Geological formation
Lithology
Primary Limestone, sandstone, conglomerate
Other Marl, tuff
Location
Coordinates 28°00′S70°18′W / 28.0°S 70.3°W / -28.0; -70.3
Approximate paleocoordinates 30°36′S54°30′W / 30.6°S 54.5°W / -30.6; -54.5
Region Atacama
Country Chile
Extent Algarrobal Basin
Relief Map of Chile.jpg
Lightgreen pog.svg
Hornitos Formation (Chile)

The Hornitos Formation is a Campanian geologic formation of the Algarrobal Basin in the Atacama Region of northern Chile. The formation comprises limestones, sandstones, conglomerates, marls and tuff. Dinosaur remains are among the fossils that have been recovered from the formation, including the sauropod Arackar licanantay . [1]

Contents

Description

The Hornillos Formation, deposited in the Algarrobal Basin, [2] comprises sandstones, limestones, conglomerates, and caliches, intercalated with lavas and andesitic breccias and various volcanic rocks. Between these last is a conspicuous layer of rhyo-dactitic lithic tuff, which reaches up to 10 metres (33 ft) in thickness. Bones of indeterminate titanosaurs appear in a marly limestone stratum of 10 metres (33 ft) thick with decimeter-sized calcareous concretions. The smallest pieces were found as rollings, whereas the larger piece was included in the limestone. [3]

The Hornitos Formation formerly was thought to be of Paleocene to Eocene age. [4] The formation may be older and belong to the Early Cretaceous, as a granite intruded the rocks about 105 ± 10 Ma. [5]

Fossil content

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

Sauropods

Sauropods of the Hornitos Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages
Arackar [6] A. licanantay Atacama Region Campanian to MaatrishtianFemur, Humerus and IschiumA lithostrotian titanosaur; closely related to Isisaurus colberti .
Arackar licanantay.jpg

See also

References

  1. Weishampel, et al. (2004). "Dinosaur distribution." pp. 517–607.
  2. Abad, 1982, p. 5
  3. Hornitos at Fossilworks.org
  4. Rivera Cabello, 1985, p. 5
  5. Rivano et al., 1986, p. 28
  6. Rubilar-Rogers D, Vargas AO, Riga BG, Soto-Acuña S, Alarcón-Muñoz J, Iriarte-Díaz J, Arévalo C, Gutstein CS (2021). "Arackar licanantay gen. et sp. nov. a new lithostrotian (Dinosauria, Sauropoda) from the Upper Cretaceous of the Atacama Region, northern Chile". Cretaceous Research. 124: Article 104802. Bibcode:2021CrRes.12404802R. doi:10.1016/j.cretres.2021.104802. S2CID   233780252.

Bibliography

Further reading