Graptolites and trilobites from the Eusebio Ayala Formation (Hirnantian?–early Llandovery), Paraná Basin, eastern Paraguay

Authors
Alfaro, Marta Beatriz; Uriz, Norberto Javier; Cingolani, Carlos Alberto; Tortello, Marcelo Franco; Bidone, Andrea Rosa; Galeano Inchausti, Julio César
Publication Year
2013
Language
English
Format
article
Status
Published version
Description
A low-diversity graptolite fauna from the upper part of the Eusebio Ayala Formation exposed in the intracratonic Paraná Basin of eastern Paraguay is reported herein. The sections studied are composed dominantly of red micaceous mudstones with intercalations of purple sandstones from a series of clay quarries (Santa Elena; Galeano; Western Itauguá) around Itauguá city. The graptolites Metaclimacograptus sp., Normalograptus cf. ajjeri (Legrand), and Normalograptus cf. medius (Törnquist) indicate an early Llandovery age for the upper Eusebio Ayala unit. Compared to coeval, postglacial successions in southwestern Gondwana, the graptolites studied have their closest affinities with those from the Rhuddanian lower Lipeón (Subandean Ranges, northwestern Argentina) and La Chilca (Precordillera) formations. In addition, a trilobite assemblage dominated by the genus Mucronaspis was collected from the Eusebio Ayala Formation type locality near Eusebio Ayala city. The latter represents an isolated small outcrop which seems to be latest Ordovician (Hirnantian) in age.
Fil: Alfaro, Marta Beatriz. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina
Fil: Uriz, Norberto Javier. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina
Fil: Cingolani, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina
Fil: Tortello, Marcelo Franco. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Bidone, Andrea Rosa. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina
Fil: Galeano Inchausti, Julio César. Ministerio de Obras Públicas y Comunicaciones de Paraguay; Paraguay
Subject
Graptolites
Trilobites
Eusebio Ayala Formation
Hirnantian?-Llandovery
Paraguay
Oceanografía, Hidrología, Recursos Hídricos
Ciencias de la Tierra y relacionadas con el Medio Ambiente
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/23870