Abstract

HEREDIA, Susana  and  BERESI, Matilde S.. The Empozada Formation and its relationship with San Isidro Formation (nom. nov.), Ordovician of the Mendoza Precordillera. Rev. Asoc. Geol. Argent. [online]. 2004, vol.59, n.2, pp.178-192. ISSN 0004-4822.

A new stratigraphic succession is established for the Ordovician deposits of the San Isidro area, Precordillera of Mendoza. Llanvirn talus olisthostromic / olistholith deposits and Caradoc- Ashgill siliciclastic deposits are cropping out in the San Isidro region. The basal siliciclastic sequence deposited in a talus with steep gradient, is now defined as the Estancia San Isidro Formation (nom. nov.). The overlaying succession is the Empozada Formation, which is redefined from the Caradoc-Ashgill maintaining the major part exposures following Harrington's original definition, but modified the description of the lower member. These sequences characterized the Central Precordillera of Mendoza province. The Estancia San Isidro Formation can be correlated to other contemporaneous sequences of the western margin of the Precordillera basin, which are referred to an extensive widespread convulsive event from the Llanvirn.

Keywords : Biostratigraphy; Empozada Formation; Estancia San Isidro Formation; Ordovician; Precordillera; Mendoza.

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