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.Santa Juana Formation at Fossilworks.org Lithologies range from conglomerate sandstone, arkosic sandstone, siltstone and mudstone.Nielsen, 2005
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:
Flora
Asterotheca fuchsii A. rigbyana Baiera africana B. furcata Cladophlebis mendozaensis Dicroidium coriaceum D. crassinervis D. elongatum D. odontopteroides Dictyophyllum fuenzalidai D. tenuifolium Gleichenites quilacoyensis Gontriglossa reinerae Heidiphyllum elongatum Kurtziana cacheutensis Linguifolium lilleanum L. steinmannii Pterophyllum santajuanensisMoisan et al., 2010 Rissikia media Saportaea dichotoma Sphenobaiera africana Sphenopteris cf. polymorpha Taeniopteris sp. Taeniopteris vittata Telemachus elongatus Thaumatopteris rothii Todites chilensis cf. Pseudoctenis fissa Cladophlebis sp. Dicroidium sp. Gleichenites sp. ?Antevsia sp.
Insects
Bandelnielsenia chilenaMartins Neto et al., 2003 Ischichucasyne santajuanaensis Ademosyne sp.
Branchiopoda Polygrapta troncosoi Menucoestheria terneraensis
See also
Chañares Formation, fossiliferous formation of the Ischigualasto-Villa Unión Basin, Argentina Candelária Formation, contemporaneous fossiliferous formation of the Paraná Basin, Brazil Molteno Formation, contemporaneous fossiliferous formation of Lesotho and South Africa Pebbly Arkose Formation, contemporaneous fossiliferous formation of Botswana, Zambia and Zimbabwe Denmark Hill Insect Bed, contemporaneous fossiliferous unit of Queensland, Australia Madygen Formation, contemporaneous Lagerstätte of Kyrgyzstan
References
Bibliogahy