Where: Santa Cruz, Argentina (46.0° S, 71.3° W: paleocoordinates 46.4° S, 67.9° W)
• coordinate estimated from map
• outcrop-level geographic resolution
When: Río Mayo Formation, Mayoan (11.0 - 10.0 Ma)
• It's near the boundary between Serravalian and Tortonian (~11.63Ma)
•We follow Escosteguy et al. (2003) and assign the fossiliferous section to the Río Mayo Formation, based on the presence of cross-bedding bluish grey sandstone plus paleosoils that characterize this formation.
•The absolute Ar40/Ar39 dates indicate an age of 12.18± 0.15–12.2 Ma for Pedregoso Formation at the margins of Arroyo Pedregoso, and an age of about 11.8 Ma for a level just below the fossil level of Río Mayo Formation at El Portezuelo on Cerro Guenguel (Dal Molin and Franchi 1996; Madden et al. 1997; De Iuliis et al. 2008). Dunn et al. (2015) mentioned an age of 11.78 for Río Mayo Formation (referring to the age of Madden et al. 1997) and an age of 12.2–13.3 for the underlying formation (El Portezuelo Formation according to Escosteguy et al. 2003), both at Cerro Guenguel. Finally, Rivas et al. (2015) obtained ages of 12.3±0.16 Ma, and 12.18±0.4 Ma for the upper levels of Oscuro Formation.
•These ages place the Pedregoso/El Portezuelo, and Río Mayo formations around the Serravallian–Tortonian boundary (middle–late Miocene, 11.63 Ma; Cohen et al. 2013), between the older Collón Curá Formation (14.86±0.13 Ma; Bilmes et al. 2013) and Río Frías Formation (14.83±0.17 Ma; de la Cruz and Cortés 2011), and the younger Arroyo Chasicó Formation (9.23±0.09 Ma; Schultz et al. 2004). These ages partially overlap with La Victoria and Villavieja formations (13.5–11.8 Ma; Madden et al. 1997).
• formation-level stratigraphic resolution
Environment/lithology: terrestrial; coarse-grained, gray sandstone
•Above this fossiliferous level, there is a 1.5 m level of whitish gray claystone with bioturbation, then a 2 m level of bluish grey sandstone of medium to coarse grain, with moderately horizontal bed- ding at the base that changes to cross bedding on the top. Above and below the described section, are outcrop banks of sandstone and siltstone with occasional more clayey lev- els, some of these corresponding to paleosoils. The section is truncated by an erosional unconformity, and is overlain by stratified gravel covered by till, with a thickness of more than 10 m, preliminary assigned to Pliocene glaciations. We follow Escosteguy et al. (2003) and assign the fossiliferous section to the Río Mayo Formation, based on the presence of cross-bedding bluish grey sandstone plus paleosoils that characterize this formation.
Size classes: macrofossils, mesofossils
Collection methods: The specimen was found disarticulated
Primary reference: L. R. González-Ruiz, A. Reato, M. Cano and O. Martinez. 2016. Old and new specimens of a poorly known glyptodont from the Miocene of Patagonia and their biochronological implications. Acta Palaeontologica Polonica 62(1):181-194 [P. Mannion/M. Kouvari]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 205807: authorized by Philip Mannion, entered by Miranta Kouvari on 23.10.2019, edited by Grace Varnham
Creative Commons license: CC BY (attribution)
Taxonomic list
| Mammalia | |
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Megatherium sp. Cuvier 1796 edentate | |
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