Paleoclimate estimates for the Paleogene?Neogene in southern South America using fossil leaves as proxies

BÁRBARA VENTO; GABRIELA GRISELDA PUEBLA; DIEGO PINZÓN; MERCEDES B. PRÁMPARO

COMPTES RENDUS PALEVOL

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2021 vol. 20 p. 29 - 48

1631-0683

It is widely recognized that fossil leaves are good proxies for paleoclimate estimates, and that leaf physiognomy analysis is a traditional technique used to make climate estimates. There are only a few paleoclimate reconstructions for the southern part of South America based on the mentioned technique. Here, we report climate parameters using fossil leaves from the Río Turbio (Eocene?Oligocene) and Río Guillermo (Oligocene?early Miocene?) formations in southern South America, Cuenca Austral, Argentina. We used univariate (Leaf Margin and Leaf Foliar Area Analysis) and multivariate methods (CLAMP, DiLP) as also two datasets from South America and Southern Hemisphere. Lower and upper members of the Río Turbio Formation evidenced a mixed paleoflora represented by paratropical together with cool-temperate taxa as Nothofagus, with a similar percentage of untoothed fossil leaves. Climate estimates indicated warm and humid conditions for both Río Turbio Formation members. The Río Guillermo Formation was represented by most of cooltemperate elements mainly Nothofagus and most of them with toothed margins. The paleoclimate analysis indicated a decrease in temperature and precipitation when comparing the two studied formations. Nowadays, modern temperate forests developed in Southern Argentina have a plant composition and climate most similar to the estimates made for the Río Guillermo Formation.