Trilobites tremadocianos de Abra de Zenta (Cordillera Oriental, provincias de Jujuy y Salta, Argentina)

Abstract

En este trabajo se describe con detalle una asociación de trilobites de la Formación Santa Rosita aflorante en la sierra de Zenta (provincias de Salta y Jujuy, noroeste de Argentina). La sección fosilífera se localiza en el paraje Abra de Zenta y consiste en lutitas oscuras y verdosas, areniscas e intercalaciones de calcarenitas subordinadas. La asociación está compuesta por Leptoplastides marianus (Hoek), Asaphellus catamarcensis Kobayashi y Kainella sp. Estos taxones constituyen herramientas bioestratigráficas valiosas para el reconocimiento del Tremadociano inferior (Ordovícico Inferior) de la Cordillera Oriental.A trilobite assemblage from the Santa Rosita Formation of the Zenta Range (Salta and Jujuy Provinces, northwestern Argentina) is fully described. The fossiliferous section is located at Abra de Zenta and consists of greenish and dark shales and sandstones with few intercalations of marls. The assemblage is composed of Leptoplastides marianus (Hoek), Asaphellus catamarcensis Kobayashi and Kainella sp. These taxa constitute valuable biostratigraphic tools for recognition of the lower Tremadocian (Lower Ordovician) of the Cordillera Oriental.A trilobite assemblage from the Santa Rosita Formation of the Zenta Range (Salta and Jujuy Provinces, northwestern Argentina) is fully described. The fossiliferous section is located at Abra de Zenta and consists of greenish and dark shales and sandstones with few intercalations of marls. The assemblage is composed of Leptoplastides marianus (Hoek), Asaphellus catamarcensis Kobayashi and Kainella sp. These taxa constitute valuable biostratigraphic tools for recognition of the lower Tremadocian (Lower Ordovician) of the Cordillera Oriental.