Paleoclimatic evidences from the late Pleistocene-middle Holocene at Paso Otero 5 site (Pampean region, Argentina)

GUTIERREZ, M. A., G. MARTÍNEZ Y P. STEFFAN

Miramar, Córdoba

Congreso; Holocene environmental catastrophes in South America: From the Lowlands to the Andes; 2005

ICSU DARK NATURE – IGCP 490

Paso Otero 5 is an archaeological site where ca. 10 taxa of extinct mammals has been recovered in association with human artifacts, dated between 10,400-10,000 years BP. A complete stratigraphic record spanning the late Quaternary is available at the site which allows to conduct a variety of analyses on fauna, lithic, stratigraphy, chronology, palynofacies, silicophytoliths, and stable isotopes on gastropods. The aim of this paper is to discuss the paleoclimatic changes occurred during the late Pleistocene to middle Holocene (ca. 10,400–4000 years BP) in order to a) identify the most remarkable fluctuations in terms of intensity within the general climatic trends during the studied period, and b) to describe the paleoenvironmental scenario during the human occupation from the site perspective. Although the different lines of evidence studied here present an uneven degree of resolution some common paleoclimatic considerations can be drawn. The results suggest that previous and during the human occupation (ca. pre-10,400-10,000 years BP), the climatic conditions were arid, with a cold pulse as they are indicated by the palynofacies, silicobioliths and stable isotope records. Although less intense, these arid conditions would have continued until the early Holocene at ca. 8800 years BP. However, a wetter and warmer pulse is register by the stable isotopes, palynofacies, silicobiolith, sediment and pedological evidences at ca. 10,000 years BP. Since ca. 6600 to 4200 years BP a change to a more humid and probably warmer conditions are suggested by geological and palynofacial information.