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Santa Juana Formation
Santa Juana Formation
Stratigraphic range: Carnian; ~235–222 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	Talcamávida-Gomero, Unihue & Quilacoya Members
Overlies	Coastal Batholith of central Chile
Thickness	Unknown
Lithology
Primary	Conglomerate, sandstone, siltstone
Other	Arkosic sandstone, mudstone, volcanic rock, anthracite
Location
Coordinates	37°12′S 73°00′W / 37.2°S 73.0°W
Approximate paleocoordinates	53°48′S 39°54′W / 53.8°S 39.9°W
Region	Bío Bío Region
Country	Chile
Type section
Named for	Santa Juana
Named by	Ferraris
Year defined	1981
	Santa Juana Formation (Chile)

Santa Juana Formation a Late Triassic (Carnian stage) sedimentary rock formation near Santa Juana in the lower course of the Biobío River in south-central Chile.^[1] Lithologies range from conglomerate sandstone, arkosic sandstone, siltstone and mudstone.^[2]

Description

The sediments that consolidate into the rocks of the formation deposited in alluvial, fluvial, lacustrine and playa lake environment. Overall, the formation is rich in plant fossils.^[2]

The formation was deposited over the rocks of the Coastal Batholith of central Chile in a sedimentary basin that formed along the Gastre Fault. It has been posited that the basin developed as a rift during the early break-up of Gondwana in the Triassic.^[2]

Fossil content

The following fossils have been reported from the formation:^[1]

Flora

Insects

Branchiopoda

References

^ ^a ^b Santa Juana Formation at Fossilworks.org
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x Nielsen, 2005
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p Moisan et al., 2010
^ ^a ^b ^c ^d ^e Martins Neto et al., 2003

Bibliogahy

Moisan, P.; Abad, E.; Bomfleur, B.; Kerp, H. (2010), "A Late Triassic flora from Gomero (Santa Juana Formation), Chile", Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 258: 89–106, doi:10.1127/0077-7749/2010/0087
Nielsen, Sven N (2005), "The Triassic Santa Juana Formation at the lower Biobío River, south central Chile", Journal of South American Earth Sciences, 19 (4): 547–562, Bibcode:2005JSAES..19..547N, doi:10.1016/j.jsames.2005.06.002
Martins Neto, R. G.; Gallego, O. F.; Melchor, R. N. (2003), "The Triassic insect fauna from South America (Argentina, Brazil and Chile): a checklist (except Blattoptera and Coleoptera) and descriptions of new taxa", Acta Zoologica Cracoviensia, 46 (Suppl): 229–256

[FW-1] Santa Juana Formation at Fossilworks.org

[Nielsen2005-2] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x Nielsen, 2005

[Moisan2010-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p Moisan et al., 2010

[Martins2003-4] Martins Neto et al., 2003

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[2]

[3]

[4]

Santa Juana Formation