Isotopic glimpses from the Nahuel Huapi region in the last 20,000 years from extinct and extant species

CHICHKOYAN KARINA VANESA; TESSONE AUGUSTO; LANATA JOSÉ LUIS; LEZCANO MAXIMILIANO; HAJDUK ADAM; PALMQVIST PAUL

Congreso; 4th Palaeontological Virtual Congress; 2023

Fifteen new stable isotopic measurements from the Nahuel Huapi region (Patagonia, Argentina) of the last 20,000 years BP are provided. These includes the first isotopic estimates derived for the extinct Megatherium americanum and Mylodontidae (Xenarthra) from the Last Glacial Maximum of Patagonia. Also, Hippocamelus sp., Hippocamelus bisculus and Lamaguanicoe (Artiodactyla) were measured. The sample was recollected in a paleontological site and two rock shelters (El Trébol and Arroyo Corral) with paleontological and archaeological levels. The particular record of the NahuelHuapi region allows expanding the range of isotopic studies in Patagonia and South America Southern Cone for this crucial period, providing this type ofinformation in the studied region for the first time. The δ13C and δ15N values allowin reconstructing the paleoenvironment between the Late Pleistocene and Holocene, when drastic climatic and biotic events occurred that shaped the modern landscape and faunal communities (e.g., megamammal extinction and the first human dispersal in the Americas). The δ13C signature remains stable along the entire period, only M. americanum shows less depleted δ13C. The δ15N signature supports fast Pleistocene-Holocene environmental changes, from glacial (i.e., cold and dry) in the Last Glacial Maximum to warmer and more humid conditions in Post Last Glacial Maximum times. An abrupt West to East gradient is maintained along the 20,000 years BP in this region, being El Trébol moister than Arroyo Corral. Despite these environmental differences, earliest human signs in both sites were dated circa 10,000 BP, related with the first dispersal wave in the Americas.