Glacial Deposits in the Río del Peñón Formation (Late Carboniferous), Río Blanco Basin, Northwestern Argentina

GULBRANSON, E.; LIMARINO, C.O.; MARENSSI, S.; MONTANEZ, I.; TABOR, N.; DAVYDOV, V.; COLOMBI, C.E.

Latin American Journal of Sedimentology and Basin Analysis

Asociación Argentina de Sedimentología

Año: 2008 vol. 15 p. 129 - 142

1669 7316

The Río del Peñón Formation (Borrello, 1955 nom. subst. González y Bossi, 1986) forms the upper part of the Late Paleozoic sequence outcropping in the Río Blanco anticline (northwest of Precordillera, La Rioja Province). This unit is basically composed of a thick (1270 m.) siliciclastic sequence of sandstones and mudstones including thin levels of coal and scarce conglomerates (Scalabrini Ortiz, 1972; Scalabrini Ortiz and Arrondo, 1973; González and Bossi, 1986). These rocks represent a complex interfingering of shallow marine and fluvial deposits resulting from a fluctuating sea level during the Late Carboniferous-Early Permian transition. The Río del Peñón Formation covers by means of an erosive surface andesites and volcanic breccias of the Punta del Agua Formation. Despite well known Late Carboniferous glacigenic deposits from different localities within Precordillera (López Gamundí, 1987, 1997; López Gamundí and Martinez, 2000; Marenssi et al., 2004; Limarino and Spalletti, 2006), they have been never described or mentioned in the Río del Peñón Formation yet. The finding of glacial-related sediments in this unit allow not only increasing the knowledge of the paleogeographic distribution of the gondwanic glacial deposits but also, as we will see, improving the knowledge on the age of the glacial event in the Río Blanco Basin.