Different perspectives of taphonomic studies from Salto de Piedra fossil site (Pampa, Argentina)

FERNÁNDEZ-JALVO, YOLANDA; MARIN-MONFORT, MARÍA DOLORES; DEMURO, MARTINA; GÓMEZ, GUSTAVO; BONINI, RICARDO; BELLINZONI, JONATHAN; GARCÍA-MORATO, SARA; GUTIÉRREZ, MARÍA A.; FERNÁNDEZ, FERNANDO; ALBERDI, MARÍA TERESA; MORENO-GARCÍA, MARTA; CERDEÑO, ESPERANZA; ARNOLD, LEE; TOMASSINI, RODRIGO; GUILLERMO, AILÍN; GARRONE, MARIANA; STEFFAN, PAMELA; SANZ-PÉREZ, DÁNAE; PRADO, JOSÉ LUIS

Comacchio

Encuentro; 10th TAPHOS International Meeting on Taphonomy and Fossilization; 2025

Università degli Studi di Ferrara

The fossil site of Salto de Piedra (in the Argentine Pampas, near the town of Olavarría) is located in the upper basin of the Tapalqué Creek, which fossil-bearing strata cover the last 150 ka BP. This period includes the Pleistocene-Holocene (glacial-interglacial) transition. Different taphonomic methods have been applied to the small mammals, macro- and megafauna, and gastropods recorded at Salto de Piedra. Systematic excavations have provided a relatively large fossil collection of the small, meso- and large mammal fossils. The different taphonomic methods, applied to different taxonomic groups, have allowed us to obtain a conclusive interpretation of the formation of the site and exclude potential reworking of these fossils recorded in a riverbank site. Re-sedimentation, however, has affected these fossil assemblages. The taphonomic results, combined with taxonomic identifications and radiometric dating, suggest that the biozones established in the Pampas region should be revised. The taphonomic results obtained at the Salto de Piedra site, combined with palaeoecological analyses of small mammals and gastropods, as well as detailed radiometric dating, have also allowed us to conclude that climatic events in the Pampean region were milder than in the northern hemisphere. This evidence is currently being verified on the other side of the Atlantic, in South Africa. Finally, the period covered by the Salto de Piedra fossils is particularly interesting in this area, since representatives of the most charismatic megafauna, such as Megatherium (the giant sloth), Glyptodon (armoured mammals) and Smilodon (saber-toothed cats) became extinct at the beginning of the Holocene. Salto de Piedra represents the natural context (there is no evidence of human presence), in contrast to the nearby human settlements in the area. During the Late Pleistocene (c. 13 ka BP), humans arrived in the Argentinean Pampas and various authors have suggested that they were responsible for the extinction of the megafauna. Based on the taphonomic modifications recorded on the bone surfaces of the megafaunal fossils from Salto de Piedra, we can discuss the role of humans versus climate in the debate of the megafauna mass extinction.