Hornitos Formation

Hornitos Formation
Stratigraphic range: Late Cretaceous, Campanian–Maastrichtian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Lithology
Primary	Limestone, sandstone, conglomerate
Other	Marl, tuff
Location
Coordinates	28°00′S 70°18′W / 28.0°S 70.3°W / -28.0; -70.3
Approximate paleocoordinates	30°36′S 54°30′W / 30.6°S 54.5°W / -30.6; -54.5
Region	Atacama
Country	Chile
Extent	Algarrobal Basin
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]

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]

References

^ Weishampel, et al. (2004). "Dinosaur distribution." pp. 517–607.
^ Abad, 1982, p. 5
^ Hornitos at Fossilworks.org
^ Rivera Cabello, 1985, p. 5
^ Rivano et al., 1986, p. 28

Bibliography

Abad E., Eduardo. 1982. [[1] Un modelo de depositación de uranio en la Cuenca de Algarrobal, Vallenar, Chile], 1–37. III Congreso Geológico Chileno. Accessed 2018-09-08.
Rivano G., Sergio et al.. 1986. Antecedentes radiométricos para una edad cretácica inferior de la Formación Las Chilcas. Andean Geology 27. 27–32. Accessed 2018-09-08.
Rivera Cabello, Sergio. 1985. [[2] Una discusión sobre la edad de las formaciones Cerrilos y Hornitos, Región de Atacama], 1–13. IV Congreso Geológico Chileno. Accessed 2018-09-08.
Weishampel, David B.; Peter Dodson, and Halszka Osmólska (eds.). 2004. The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21. ISBN 0-520-24209-2

G. Chong Diaz. 1985. Hallazgo de restos oseos de dinosaurios en la Formación Hornitos – Tercera Region de Atacama – Chile. IV Congreso Geologico Chileno 152-161
P. Salinas, P. Sepúlveda, and L. G. Marshall. 1991. Hallazgo de restos oseos de dinosaurios (saurópodos) en la Formación Pajonales (Cretácico Superior), Sierra de Almeyda, Región de Antofagasta, Chile: implicancia cronológica [Discovery of skeletal remains of dinosaurs (sauropods) in the Pajonales Formation (Upper Cretaceous), Sierra de Almeyda, Antofagasta Region, Chile: chronological implications]. 6e Congreso Geológico Chileño, Viña del Mar. Resumenes Expandidos. Servicio Nacional de Geología y Mineria, Chile 534-537

Geology of Chile

Terranes

Sedimentary
formations
and groups

Cretaceous	Baños del Flaco Fm. Cerro Colorado Fm. Chacarilla Fm. Chañarcillo Gp. Coihaique Gp. Divisadero Gp. Dorotea Fm. Hornitos Fm. La Liga Fm. Ñirehuao Fm. Punta del Cobre Fm. Purilactis Gp. Quiriquina Fm. Viñita Fm. Way Gp. Zapata Fm.
Jurassic	Chacarilla Fm. Coihaique Gp. Ibáñez Fm. La Liga Fm. La Negra Fm. Nacientes del Biobío Fm. Nacientes del Teno Fm. Pan de Azúcar Fm. Tobífera Fm.
Triassic	Canto del Agua Fm. Choiyoi Gp. Panguipulli Fm. Santa Juana Fm. Tralcán Fm.