New conodont species and biostratigraphy of the Santa Rosita Formation (upper Furongian–Tremadocian) in the Tilcara Range, Cordillera Oriental of Jujuy, Argentina

Abstract

A new conodont collection from the Alfarcito area of the Tilcara Range, Cordillera Oriental of northwestern Argentina, has been studied. The Santa Rosita Formation exposed in this area consists of the Tilcara, Casa Colorada, Pico de Halcón, Alfarcito, Rupasca and Humacha members, which have a combined total thickness of ca. 1100 m. The sequence is composed of interbedded shales and sandstones, including calcarenites and coquinas, mostly appearing in the upper parts of the units. An abundant fauna of conodonts (ca. 11 000 elements), associated with graptolites and trilobites, was recorded. The biostratigraphic analysis allows for the identification of the Cordylodus intermedius and C. lindstromi sensu lato zones at the base of the Alfarcito Member. The C. angulatus Zone spans the upper part of the latter unit, and the Paltodus deltifer Zone (Paltodus deltifer pristinus and P. deltifer deltifer subzones) is identified in the Rupasca and Humacha members. The new species Acanthodus raqueli, A. humachensis, Utahconus tortibasis, U. scandodiformis, U. purmamarcensis, Variabiloconus crassus, Kallidontus gondwanicus and Acodus primitivus are recorded from the two latter biozones and they are described herein. The genera Acanthodus and Variabiloconus are emended, and a new genus Tilcarodus is created to include T. humahuacensis (Albanesi and Aceñolaza). Copyright © 2012 John Wiley & Sons, Ltd.

Linguloidean brachiopods from the Lower Ordovician (Tremadocian) of northwestern Argentina

“…The lower part of the Humacha Member has been attributed to the sparsely fossiliferous unzoned interval between the Bienvillia tetragonalis and Notopeltis orthometopa biozones (Salas & Vaccari 2012), while its upper part could be assigned to the upper Tremadocian Notopeltis orthometopa Zone (Harrington & Leanza 1957, Waisfeld & Vaccari 2008a, Zeballo & Albanesi 2013.…”

Biofacies and palaeoenvironments of conodonts in Cambro‐Ordovician sequences of the Quebrada de Humahuaca, Cordillera Oriental of Jujuy, Argentina

“…Composite stratigraphic column of the Santa Rosita Formation at the Tilcara Range, with transgressive–regressive cycles (after Buatois et al ., ; Zeballo et al ., , ; Zeballo and Albanesi, , ) and main eustatic events in dark grey (after Miller et al ., , , and Lehnert et al ., ) (Conod. : conodonts, Gr.…”

BroeggeriaWalcott and other upper Cambrian and Tremadocian linguloid brachiopods from NW Argentina

“…Stratigraphic distribution of brachiopods discussed in this paper. Biostratigraphic scheme of the Cordillera Oriental after Zeballo and Tortello (); Waisfeld and Vaccari (); Zeballo et al (); Albanesi et al (); Voldman et al () and Toro et al ().…”

“…stenorhachis / Leptoplastides Association (Toro et al, ). This interval can confidently be correlated with the Broeggeria‐ bearing strata exposed at Nazareno, which according to Tortello and Esteban () lie immediately below the FAD of N. orthometopa (the ‘unnamed zone’ sensu Zeballo and Albanesi, ).…”