Soncco Formation

The Soncco Formation is a Late Eocene to Early Oligocene geologic formation in southern Peru. The base of the formation at the contact with the K'ayra Formation is dated using fission track analysis at 43 Ma and the top, the contact with the Punacancha Formation, at 30 Ma.[1] In other places the Tinajani Formation overlies the Soncco Formation.[2] The formation has a thickness of 1,600 metres (5,200 ft).[3]

Soncco Formation Stratigraphic range: Late Eocene-Early Oligocene 43–30 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	San Jerónimo Group
Sub-units	C, D & E Members
Underlies	Punacancha Fm., Tinajani Fm.
Overlies	K'ayra Formation
Thickness	1,600 m (5,200 ft)
Lithology
Primary	Conglomerate, sandstone
Other	Coal, lacustrine limestone
Location
Coordinates	13°20′12″S 71°44′28″W
Region	Puno & Cusco Regions
Country	Peru
Type section
Named for	Soncco
Paleogeography of Northern South America, 35 Ma by Ron Blakey

Type locality of the Soncco Formation in Peru

Misattributed ornithopod tracks

The formation was first dated to the Cretaceous, and fossil ornithopod tracks had been reported.[4] Over 9,000 fossil tracks are said to be found within this formation. As the formation has been dated to the Paleogene, the tracks could not be attributed to dinosaurs.[1]

References

1. Carlotto, 2016, p.522
2. La Torre et al., 2004, p.116
3. Cusco.gob, 2015, p.120
4. Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.

Bibliography

• N., N. 2015. Plan de desarrollo urbano Cusco al 2023, 116-150. Cusco.gob. Accessed 2017-06-05.
• Latorre, O. Omar; F. Yovani Orós; Thierry Sempere; Michel Fornari, and Víctor Carlotto. 2004. Estratigrafía y evolución paleógena del área de Llalli-Macarí (Departamento de Puno). SGP 5. 111-119. Accessed 2017-06-05.
• Carlotto, Víctor. 2016. Dataciones por trazas de fisión en los depósitos continentales terciarios de la Región de Cusco, 521-524. XIII Congreso Peruano de Geología. Accessed 2017-06-05.
• 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