Pircancha Formation

Pircancha Formation
Stratigraphic range: Floian-Dapingian ~478–466  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Thickness	1,800 m (5,900 ft)
Lithology
Primary	Mudstone
Other	Shale, sandstone, pyrite
Location
Coordinates	21°00′S65°00′W / 21.0°S 65.0°W / -21.0; -65.0
Approximate paleocoordinates	45°18′S129°06′W / 45.3°S 129.1°W / -45.3; -129.1
Region	Tarija Department
Country	Bolivia
Pircancha Formation (Bolivia)

The Pircancha Formation is a Floian to Dapingian geologic formation of southern Bolivia. The green mudstones, shales and sandstones were deposited in a shallow to open marine environment. ^{[1] [2]} The fossil Pircanchaspis rinconensis is named after the formation.

Fossil content

The formation has provided the following fossils:

• Bactroceras boliviensis ^[3]
• Baltograptus deflexus , B. minutus
• Pircanchaspis rinconensis
• Pseudophyllograptus densus
• Tetragraptus cf. amii
• Didymograptus cf. suecicus
• Basilicus sp.
• Dinorthis sp.
• Famatinolithus sp.
• Geragnostus sp.
• Hoekaspis sp.
• Phyllograptus sp.
• Synhomalonotus sp.

See also

• List of fossiliferous stratigraphic units in Bolivia

References

1. "Rincon", "Escuela Seccional de Puesto Grande" at Fossilworks.org
2. Pircancha Fm., Tarija and Chilcayo at Fossilworks.org
3. Aubrechtová, 2015

Bibliography

• Aubrechtová, Martina (2015), "A revision of the Ordovician cephalopod Bactrites sandbergeri Barrande: systematic position and palaeobiogeography of Bactroceras", Geobios , 48 (3): 193–211, Bibcode:2015Geobi..48..193A, doi:10.1016/j.geobios.2015.03.002 , retrieved 2019-03-03

Further reading

• B.-D. Erdtmann, B. Weber, H.-P. Schultze and S. Egenhoff. 2000. A possible agnathan plate from the lower Arenig (Lower Ordovician) of South Bolivia. Journal of Vertebrate Paleontology 20(2):394-399
• M. Toro and S. Fernandez. 1979. Los fósiles de la formación Pircancha aflorante en Chilcayo, Provincia Méndez - Depto. Tarija. Revista de la Academia Nacional de Ciencas de Bolivia 163-169