Cancañiri Formation

Cancañiri Formation
Stratigraphic range: Katian-Hirnantian ~460–439 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Underlies	Uncía Formation
Overlies	Amutara & San Benito Formations
Thickness	Up to 1,500 m (4,900 ft)
Lithology
Primary	Sandstone, shale
Other	Siltstone
Location
Coordinates	17.7°S 66.3°W / -17.7; -66.3
Approximate paleocoordinates	44.2°S 127.4°W / -44.2; -127.4
Region	Cochabamba & Potosí Departments
Country	Bolivia
Extent	Cordillera Oriental
Type section
Named for	Cancañiri
Cancañiri Formation (Bolivia)

The Cancañiri Formation, also named as Cancañiri Tillite, is a Katian to Hirnantian geologic formation of central Bolivia. The pebbly, argillaceous sandstones, shales and siltstones of the up to 1,500 metres (4,900 ft) thick formation,[1] were deposited in a glacial foreshore to deep water turbiditic environment.[2][3][4][5] The formation is named after Cancañiri, a mining town close to Llallagua, where a local legend of a possessed woman is believed.[6] The formation overlies the San Benito Formation in Cochabamba and the Amutara Formation in other parts. The Cancañiri Formation is overlain by the Uncía Formation.[7]

Fossil content

The formation has provided the following fossils:

• Destombesium pacochicoensis
• Dinorthis flabellulum
• Drabovinella curiosa
• Tunariorthis cardocanalis
• Oanduporella sp.
• Rostricellula sp.

See also

• List of fossiliferous stratigraphic units in Bolivia

References

1. Díaz Martínez, 2005, p.237
2. Díaz Martínez, 1997, p.55
3. Along "Coboce" Road near Irpa Irpa Railway Station at Fossilworks.org
4. Changolla, railway on the Cochabamba - Oruro Railway at Fossilworks.org
5. Paco Chico, ~40 km west of Potosí at Fossilworks.org
6. La Llorona de Cancañiri^[usurped]
7. Díaz Martínez, 1997, p.56

Bibliography

• Díaz Martínez, E (2005), "Procedencia y edad de las diamictitas del Paleozoico inferior de la cuenca de Perú-Bolivia (Gondwana occidental) - Provenance and age of diamictites in the lower Palaeozoic of the Peru-Bolivia basin (western Gondwana)" (PDF), Geogaceta, 38: 235–238, retrieved 2019-03-03
• Díaz Martínez, E (1997), "Facies y ambientes sedimentarias de la Formación Cancañiri (Silúrico inferior) en La Cumbre de La Paz, norte de la Cordillera Oriental de Bolivia" (PDF), Geogaceta, 22: 55–57, retrieved 2019-03-03

Further reading

• V. Havlicek and L. Branisa. 1980. Ordovician brachiopods of Bolivia: Succession of assemblages, climate control, affinity to Anglo-French and Bohemian provinces. Rozpravy Ceskoslovenske Akademie Ved. Rada Matematickych a Prirodnich Ved. Academia Praha, Prague, Czechoslovakia 90(1):1-54