Abstract

GENTILE, Rodolfo O.  and  RIBOT, Alejandro M.. Niveles de tefras en sedimentos continentales del Pleistoceno tardío-Holoceno (Provincia de Buenos Aires). Intersecciones antropol. [online]. 2001, n.2, pp.47-59. ISSN 1850-373X.

Three levels of tephra from Buenos Aires Province are recognized and characterized. They are located in the basin of Arroyo Tapalqué (Olavarría), in the vecinity of Tandil city, and in the coastal area of Camet Norte. In Olavarría the layer is embedded in fluvial sediments of the Guerrero Member (Late Pleistocene) of the Luján Formation. In Tandil it is found in aeolian deposits of the Las Animas Formation (Late Pleistocene - Holocene), while in Camet Norte it occurs in the Facies Camet Norte of the Santa Clara Formation, which has been asigned to the Late Pleistocene. Radiocarbon dates obtained by other researchers in the Arroyo Tapalqué indicate that this level was deposited between 26,930 + 860 years 14 C BP and 9990 - 10,280 years cal BP, perhaps around 19,320 - 20,470 years cal BP and 20,650 - 21,760 years cal BP. Camet Norte and Olavarría tephras are both contained in stratigraphically correlated units, though it is unknown if these levels were synchronous. The tephra in Las Animas Formation accumulated some time in the Late Pleistocene - Holocene (preconquest). In the three sites, the most abundant component of tephras is acid volcanic glass (rhyolithic to dacithic), with minor proportions of glass of more basic composition. The units which contain the tephras show a significant participation of pyroclastic material during their formation.

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