Findings of intratill striated pavements in the late Carboniferous glacial deposits of the Andean Precordillera

ALONSO MURUAGA, P.J.; LIMARINO, C.O.; SPALLETTI, L.A.; COLOMBO PIÑOL, F. Y JUÁREZ, P.

Latin American Journal of Sedimentology and Basin Analysis

Asociación Argentina de Sedimentología

Lugar: La Plata; Año: 2012 vol. 18 p. 151 - 157

1669-7316

In this paper we describe two subglacial basal contact surfaces found in the lower part of the Guandacol Formation (Frenguelli, 1944; Cuerda, 1965) in the Central Precordillera (northwestern Argentina). The Guandacol Formation is well known for containing glacial deposits, including diamictites and resedimented diamictites at the lower third of the unit (Limarino et al., 2006; Marenssi et al., 2002; Marenssi et al., 2005). According to paleontological (palynological) information, and some radiometric dating, the age of the glacial deposits is Late Visean- Early Bashkirian and therefore fits into the LPIA 2 interval of Isbell et al. (2003b). The presence of intraformational glacial pavements in the Guandacol Formation allows for a more precise history of the LPIA 2 glacial interval suggesting that interglacial periods not only separated lowfrequency climatic changes (LPIA intervals) but also were likely present within individual LPIA periods (high-frequency climatic changes). In addition, palynological data and radiometric evidence is discussed in order to be more precise about the age of the intraformational pavements.