Resumen

ZEBALLO, Fernando J.; ALBANESI, Guillermo L.  y  ORTEGA, Gladys. Conodont and graptolite faunas from the Alfarcito and Rupasca Formations (Tremadocian) from the Alfarcito area, Tilcara, Oriental Cordillera of Jujuy, Argentina. Part 1: Biostratigraphy. Ameghiniana [online]. 2005, vol.42, n.1, pp.39-46. ISSN 1851-8044.

The conodont fauna corresponds to the Cordylodus angulatus and Paltodus deltifer zones ( Paltodus deltifer pristinus Subzone), and graptolites represent Rhabdinopora flabelliformis flabelliformis (Eichwald). The conodonts recovered suggest a late early to early late Tremadocian age, and the graptolite species is the youngest representative of the group registered in the Eastern Cordillera up to date. A preliminary biostratigraphic scheme with mentioned biozones and associated trilobites is presented for the study area. The conodont fauna is similar to that of the Atlantic Realm, but it includes also some characteristic taxa of the Midcontinent Realm. This mixture of taxa, typical of northwestern Argentina, is assigned to the Transitional Faunal Realm.

Palabras clave : Conodonta; Graptolithina; Early Ordovician; Alfarcito; Jujuy; Argentina; Biostratigraphy.