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 / -37.2; -73.0
Approximate paleocoordinates	53°48′S 39°54′W / 53.8°S 39.9°W / -53.8; -39.9
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. Lithologies range from conglomerate sandstone, arkosic sandstone, siltstone and mudstone.

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.

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.

Fossil content

The following fossils have been reported from the formation:

See also

References