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Biostratigraphy and palaeoecology of Middle–Late Ordovician conodont and graptolite faunas of the Las Chacritas River section, Precordillera of San Juan, Argentina

Published online by Cambridge University Press:  29 January 2015

FERNANDA SERRA ,
GUILLERMO L. ALBANESI ,
GLADYS ORTEGA  and
STIG M. BERGSTRÖM
FERNANDA SERRA*
Affiliation:
CICTERRA (CONICET-UNC), Av. Vélez Sarsfield 1611, X5016GCA, Argentina
GUILLERMO L. ALBANESI
Affiliation:
CICTERRA (CONICET-UNC), Av. Vélez Sarsfield 1611, X5016GCA, Argentina
GLADYS ORTEGA
Affiliation:
CONICET CIGEA, Museo de Paleontología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba CC1598, X5000JJC, Argentina
STIG M. BERGSTRÖM
Affiliation:
School of Earth Sciences, Division of Historical Geology, The Ohio State University, 125 South Oval Mall, Columbus OH 43210, USA
*
†Author for correspondence: fserra@efn.uncor.edu
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Abstract

A conodont-graptolite biostratigraphic study was carried out on the top strata of the San Juan, Las Chacritas and Las Aguaditas formations in the La Trampa Range, Precordillera of San Juan in western Argentina. Significant conodont records in the San Juan and Las Chacritas formations allow for the recognition of the Yangtzeplacognathus crassus, Eoplacognathus pseudoplanus (Microzarkodina hagetiana and M. ozarkodella subzones) and Eoplacognathus suecicus zones of Darriwilian age. Index species and co-occurrences of graptolites and conodonts were recorded in the Las Aguaditas Formation allowing the identification of the Nemagraptus gracilis and the Pygodus anserinus zones, which represent the Sandbian Stage. These data indicate a hiatus between the Las Chacritas and the Las Aguaditas formations, corresponding to the Pygodus serra Zone and the Pterograptus elegans and Hustedograptus teretiusculus zones (upper Darriwilian). A total of 7287 identifiable conodont elements were recorded from the study section. The species frequency registered for each zone shows that Periodon and Paroistodus are the most abundant taxa, which are indicative of open marine environments. The records of particular conodont taxa, such as Histiodella, Periodon, Microzarkodina, Eoplacognathus and Baltoniodus, allow a precise global correlation with other regions such as south-central China, Baltoscandia, North America, Great Britain, Southern Australia and New Zealand. The graptolite fauna identified here are recognized worldwide in equivalent strata in the Baltic region, Great Britain, North America, China, southern Australia and New Zealand. The presence of graptolites in the ribbon limestones of the Las Chacritas Formation is documented for the first time.

Keywords

conodontsgraptolitesbiostratigraphypalaeoecologyMiddle–Upper OrdovicianCentral PrecordilleraArgentina
Type
Original Articles
Information
Geological Magazine , Volume 152 , Issue 5 , September 2015 , pp. 813 - 829
Copyright
Copyright © Cambridge University Press 2015 

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References

Albanesi, G. L. 1998. Taxonomía de conodontes de las secuencias ordovícicas del cerro Potrerillo, Precordillera Central de San Juan, R. Argentina. Actas de la Academia Nacional de Ciencias XII, 102–253.Google Scholar
Albanesi, G. L. & Astini, R. A. 2000. Bioestratigrafía de conodontes de la Formación Las Chacritas, Precordillera de San Juan, Argentina. Reunión de Comunicaciones de la Asociación Paleontológica Argentina, Mar del Plata. Ameghiniana 37, 68R.Google Scholar
Albanesi, G. L., Bejerman, A. M. & Astini, R. A. 2009. Conodont biostratigraphy and paleoenvironments of the lower Sierra de La Invernada Formation, Middle Ordovician, San Juan Precordillera, Argentina. ICOS Abstracts, Permophiles 53, 1–2.Google Scholar
Albanesi, G. L., Benedetto, J. L. & Gagnier, P.-Y. 1995. Sacabambaspis janvieri (Vertebrata) y conodontes del Llandeiliano temprano en la Formación La Cantera, Precordillera de San Juan, Argentina. Boletín Academia Nacional de Ciencias 60 (3–4), 519–44.Google Scholar
Albanesi, G. L., Bergström, S. M., Schmitz, B., Serra, F., Feltes, N. A., Voldman, G. G. & Ortega, G. 2013. Darriwilian (Middle Ordovician) δ13Ccarb chemostratigraphy in the Precordillera of Argentina: Documentation of the middle Darriwilian Isotope Carbon Excursion (MDICE) and its use for intercontinental correlation. Palaeogeography, Palaeoclimatology, Palaeoecology 389, 48–63.Google Scholar
Albanesi, G. L., Hünicken, M. A. & Barnes, C. R. 1998. Bioestratigrafía, biofacies y taxonomía de conodontes de las secuencias ordovícicas del cerro Potrerillo, Precordillera Central de San Juan, República Argentina. Boletín de la Academia Nacional de Ciencias 12, 253 pp.Google Scholar
Albanesi, G. L. & Ortega, G. 1998. Conodont and graptolite faunas from the Las Plantas Formation and equivalent units (Caradoc) in the Argentine Precordillera. Seventh International Conodont Symposium, Bologna-Modena, Abstracts: 1–2.Google Scholar
Albanesi, G. L. & Ortega, G. 2002. Advances on conodont-graptolite biostratigraphy of the Ordovician System of Argentina. In Aspects of Ordovician System in Argentina (eds Aceñolaza, F. G.), pp. 143–65. Instituto Superior de Correlación Geológica, San Miguel de Tucuman, Serie Correlación Geológica no. 16.Google Scholar
An, T.-X. & Zheng, Z. 1990. The conodonts of the marginal areas around the Ordos Basin, north China. Science Press 1–101.Google Scholar
Astini, R. A. 1994. Significado estratigráfico del Miembro Superior de la Formación San Juan, cordón de Las Chacritas, Ordovícico medio de la Precordillera de San Juan. Revista Asociación Geológica Argentina 49, 365–7.Google Scholar
Astini, R. A. 1995. Sedimentología de la Formación Las Aguaditas (talud carbonático) e implicancias estratigráficas en la cuenca precordillerana durante el Ordovícico medio. Revista de la Asociación Geológica Argentina 50, 143–64.Google Scholar
Astini, R. A. 1997. Las unidades calcáreas del Ordovícico Medio y Superior de la Precordillera Argentina como indicadores de una etapa extensional. Actas de la 2º Jornadas de Geología de Precordillera, San Juan, 8–14.Google Scholar
Astini, R. A. 1998. Stratigraphic evidence supporting the rifting, drifting and collision of the Laurentian Precordillera terrane of western Argentina. In The Proto-Andean Margin of Gondwana (eds Pankhurst, R. J. & Rapela, C. W.), pp. 11–33. Geological Society of London, Special Publication no. 142.Google Scholar
Bagnoli, G. & Stouge, S. S. 1991. Paleogeographic distribution of Arenigian (Lower Ordovician) conodonts. Anais Academia Brasileira de Ciências 63 (2), 171–83.Google Scholar
Baldis, B., Beresi, M., Bordonaro, O. & Vaca, A. 1982. Síntesis evolutiva de la Precordillera Argentina. V Congreso Latinoamericano de Geología, Buenos Aires, Argentina, IV, 399–445.Google Scholar
Baldis, B. & Chebli, W. 1969. Estructura profunda del área central de la Precordillera Sanjuanina. IV Jornadas Geológicas Argentinas I, 47–66.Google Scholar
Bergström, S. M. 1971. Conodont biostratigraphy of the Middle and Upper Ordovician of Europe and Eastern North America. In Symposium on Conodont Biostratigraphy (eds Sweet, W. & Bergström, S. M.), pp. 83–161. Geological Society of America, Boulder, Memoir no. 127.Google Scholar
Blasco, G. & Ramos, V. 1976. Graptolitos caradocianos de la Formación Yerba Loca y del Cerro La Chilca, Departamento Jáchal, Provincia de San Juan. Ameghiniana 13 (3–4), 312–29.Google Scholar
Bordonaro, O. L. 2002. Los Carbonatos cámbricos y ordovícicos de la Precordillera Argentina como Rocas de Aplicación Industrial. Ianigla, 123–6.Google Scholar
Brackebush, L. 1883. Estudio sobre la Formación Petrolífera de Jujuy. Boletín Academia Nacional de Ciencias V, 137–252.Google Scholar
Bradshaw, L. E. 1969. Conodonts from the Fort Peña Formation (Middle Ordovician), Marathon Basin, Texas. Journal of Paleontology 43 (5), 1137–68.Google Scholar
Brussa, E. D. 1996. Las graptofaunas ordivícicas de la Formación Las Aguaditas, Precordillera de San Juan, Argetnina. Parte I: Familias Thamnograptidae, Dichograptidae, Abrograptidae y Glossograptidae. Ameghiniana 33, 421–34.Google Scholar
Brussa, E. D., Maletz, J., Mitchel, C. E. & Goldman, D. 2007. Nemagraptus gracilis (J. Hall) in Bolivia and Peru. Acta Palaeontologica Sinica 46, 57–63.Google Scholar
Brussa, E. D., Toro, B. A. & Benedetto, J. L. 2003. Biostratigraphy. In Ordovician Fossils of Argentina (ed. Benedetto, J. L.), pp. 75–90. Secretaría de Ciencia y Tecnología, Universidad Nacional de Córdoba.Google Scholar
Cañas, F. L. 1999. Facies and sequences of the late Cambrian–early Ordovician carbonates of the Argentine Precordillera: a stratigraphic comparison with Laurentian platforms. In Laurentia-Gondwana Connections before Pangea (eds Ramos, V. A. & Keppie, J.D.), pp. 43–62. Geological Society of America, Special Paper 336.Google Scholar
Carrera, M. G. 1997. Análisis paleoecológicos de la fauna de poríferos del Llanvirniano tardío de la Precordillera Argentina. Ameghiniana 34, 309–16.Google Scholar
Carrera, M. G. & Astini, R. A. 1998. Valoración de las restricciones ambientales durante la transición Arenigiano-Llanvirniano, Ordovícico de la Precordillera. Revista Asociacion Geologica Argentina 53, 41–56.Google Scholar
Cuerda, A. J. 1986. Graptolitos del techo de la Formación San Juan, Precordillera de San Juan. Actas del 48 Congreso Argentino de Paleontología y Bioestratigrafía 1, 49–57.Google Scholar
Epstein, A. G., Epstein, J. B. & Harris, L. D. 1977. Conodont color alteration- an index to organic metamorphism. United States Geological Survey Professional Paper 995, 1–27.Google Scholar
Espisúa, E. 1968. El Paleozoico inferior del Río de Las Chacritas, Dpto. de Jáchal, Provincia de San Juan, con especial referencia al Silúrico. Revista Asociación Geológica Argentina 23, 297–311.Google Scholar
Feltes, N. A., Albanesi, G. L. & Bergström, S. M. 2013. Middle Darriwilian conodonts biozones from the Lower Member of the Las Aguaditas Formation, Central Precordillera of San Juan, Argentina. In Conodonts from the Andes, 3rd International Conodont Symposium (eds Albanesi, G. L. & Ortega, G.), pp. 25–31. Asociación Paleontológica Argentina, Special publication no. 13.Google Scholar
Feltes, N. A., Serra, F., Albanesi, G. L. & Voldman, G. G. 2014. La zona de Yangzteplacognathus crassus en el contacto entre las formaciones San Juan y las unidades suprayacentes en la Precordillera Central de San Juan, Argentina. Actas del XIX Congreso Geológico Argentino S2, 11. Córdoba, Argentina.Google Scholar
Finney, S. C. 1986. Graptolite biofacies and correlation of eustatic, subsidence and tectonic events in the Middle to Upper Ordovician of North America. Palaios 1, 435–61.Google Scholar
Finney, S. C. & Bergström, S. M. 1986. Biostratigraphy of the Ordovician Nemagraptus gracilis Zone. In Palaeoecology and Biostratigraphy of Graptolites (eds Hughes, C. P. & Rickards, R. B.), pp. 47–59. Geological Society of London, Special Publication no. 20.Google Scholar
Furque, G. & Cuerda, A. 1979. Precordillera de La Rioja, San Juan y Mendoza. Segundo Simposio de Geología Regional Argentina, Córdoba. Boletín de la Academia Nacional de Ciencias I, 455–522.Google Scholar
Gutiérrez-Marco, J. L., Mansilla Plaza, L., Rábano, I. & García-Bellido, D. C. 2011. Ordovician stratigraphy and paleontology of the province of Ciudad Real. ISOS Field Trip Guide, 11th International Symposium on the Ordovician System, pp. 18. Madrid, España.Google Scholar
Harris, A. G., Bergström, S. M., Ethington, R. L. & Ross, R. J. Jr 1979. Aspects of Middle and Upper Ordovician conodont biostratigraphy of carbonate facies in Nevada and southeast California and comparison with some Appalachian successions. Brigham Young University Geology Studies 26, 7–43.Google Scholar
Heredia, S. E. 1982. Pygodus anserinus Lamont and Lindström (Conodonto) en el Llandeilian de la Formación Ponón Trehué, Provincia de Mendoza. Argentina. Ameghiniana 19 (3–4), 229–33.Google Scholar
Heredia, S. E. 1998. Eoplacognathus robustus (conodonta) en la Formación Ponón Trehué (Ordovícico Inferior), Sierra Pintada, provincia de Mendoza, Argentina. Ameghiniana 35 (3), 337–44.Google Scholar
Heredia, S. E. 2012. Bioestratigrafía de conodontes del Darriwiliano medio (Ordovícico) de Argentina: la Formación Las Aguaditas, Precordillera Central. Revista Mexicana de Ciencias Geológicas 29 (1), 76–86.Google Scholar
Heredia, S. E., Beresi, M. & Peralta, S. 2005. Darriwilian conodont biostratigraphy of the Las Chacritas Formation, Central Precordillera (San Juan Province, Argentina). Geologica Acta 3, 385–94.Google Scholar
Heredia, S. E., Beresi, M. & Peralta, S. 2011. Estratigrafía y bioestratigrafía del Ordovícico Medio del río Las Chacritas, Precordillera Central de San Juan. Serie Correlación Geológica 27, 18–26.Google Scholar
Heredia, S. E., Carlorosi, J., Mestre, A. & Soria, T. 2013. Stratigraphical distribution of the Ordovician conodont Erraticodon Dzik in Argentina. Journal of South American Earth Sciences 45, 224–34.Google Scholar
Hünicken, M. A. & Ortega, G. 1987. Lower Llanvirn–Lower Caradoc (Ordovician) conodonts and graptolites from the Argentine Central Precordillera. In Conodonts: Investigative Techniques and Applications (ed. Austin, R. L.), pp. 136–45. Chichester: Ellis Horwood Ltd, British Micropalaeontological Society.Google Scholar
Keller, M., Eberlein, S. & Lehnert, O. 1993. Sedimentology of Middle Ordovician carbonates in the Argentine Precordillera: evidence of regional relative sea-level changes. Geologische Rundschau 82, 362–77.Google Scholar
Lehnert, O. 1995. Ordovizische Conodonten aus der Präkordillere Westargentiniens: Ihre Bedeutung für Stratigraphie und Paläogeographie. Erlanger Geologische Abhandlungen 125, 1–193.Google Scholar
Lehnert, O., Bergström, S. M., Keller, M. & Bordonaro, O. 1999. Ordovician (Darriwilian-Caradocian) conodonts from the San Rafael Region, West-central Argentina: biostratigraphic, paleoecologic, and paleogeographic implications. Bollettino della Società Paleontologica Italiana 37 (2–3), 199–214.Google Scholar
Löfgren, A. 1978. Arenigian and Llanvirnian conodonts from Jämtland, northern Sweden. Fossils and Strata 13, 1–129.Google Scholar
Löfgren, A. 2003. Conodont faunas with Lenodus variabilis in the upper Arenigian to lower Llanvirnian of Sweden. Acta Palaeontologica Polonica 48 (3), 417–36.Google Scholar
Löfgren, A. 2004. The conodont fauna in the Middle Ordovician Eoplacognathus pseudoplanus Zone of Baltoscandia. Geological Magazine 141, 505–24.Google Scholar
Löfgren, A. & Zhang, J. 2003. Element association and morphology in some Middle Ordovician platform equipped conodonts. Journal of Paleontology 77, 723–39.Google Scholar
Maletz, J. & Ortega, G. 1995. Ordovician graptolites of South America: palaeogeographic implications. In Ordovician Odyssey: Short Papers for the Seventh International Symposium on the Ordovician System (eds Cooper, J. D., Droser, M. L. & Finney, S. C.), pp. 189–92. The Pacific Section, Society for Sedimentary Geology (SEPM) no. 77.Google Scholar
Mestre, A. & Heredia, S. E. 2012. Darriwilian species of the genus Histiodella (Conodonta) in the Argentina Precordillera. Alcheringa 36, 141–50.Google Scholar
Mestre, A. & Heredia, S. E. 2013 a. Biostratigraphic significance of Darriwilian conodonts from Sierra de La Trampa (Central Precordillera, San Juan, Argentina). Geosciences Journal 17 (1), 43–53.Google Scholar
Mestre, A. & Heredia, S. E. 2013 b. La zona de Yangtzeplacognathus crassus (conodonta), Darriwiliano de la Precordillera Central, San Juan, Argentina. Ameghiniana 50 (4), 407–17.Google Scholar
Ortega, G. & Albanesi, G. L. 1998. The record of the Nemagraptus gracilis Zone in the Argentine Precordillera. Proceedings of the 6th International Graptolite Conference 23, 231–5. Madrid, Spain.Google Scholar
Ortega, G., Albanesi, G. L., Banchig, A. L. & Peralta, G. L. 2008. High resolution conodont-graptolite biostratigraphy in the Middle-Upper Ordovician of the Sierra de La Invernada Formation (Central Precordillera, Argentina). Geologica Acta 6 (2), 161–80.Google Scholar
Ortega, G., Albanesi, G. L. & Frigerio, S. 2007. Graptolite-conodont biostratigraphy and biofacies of the Middle Ordovician Cerro Viejo succession, San Juan, Precordillera, Argentina. Palaeogeography, Palaeoclimatology, Palaeoecology 245, 245–64.Google Scholar
Ortega, G., Albanesi, G. L. & Hünicken, M. A. 1995. Bioestratigrafía en base a conodontes y graptolitos de las Formaciones San Juan (techo) y Gualcamayo (Arenigiano-Llanvirniano) en el cerro Potrerillo, Precordillera de San Juan, Argentina. Boletín Academia Nacional de Ciencias 60 (3–4), 317–64. Córdoba, Argentina.Google Scholar
Ortega, G., Banchig, A. L., Voldman, G. G., Albanesi, G. L., Alonso, J. L., Festa, A. & Cardo, R. 2014. Nuevos registros de graptolitos y conodontes en la Formación Los Sombreros (Ordovícico), Sierra del Tontal, Precordillera de San Juan y su implicancia geológica. Actas del XIX Congreso Geológico Argentino S2, 16. Córdoba, Argentina.Google Scholar
Ortega, G. & Brussa, E. D. 1990. La subzona de Climacograptus bicornis (Caradociano temprano) en la Formación Las Plantas en su localidad tipo, Precordillera de San Juan, Argentina. Ameghiniana 27, 281–8.Google Scholar
Ortiz, A. & Zambrano, J. 1981. La Provincia geológica Precordillera Oriental. VIII Congreso Geológico Argentino 3, 59–74. San Luis, Argentina.Google Scholar
Ottone, E. G., Albanesi, G. L., Ortega, G. & Holfeltz, G. 1999. Palynomorphs, conodonts and associated graptolites from the Ordovician Los Azules Formation, Central Precordillera, Argentina. Micropaleontology 45 (3), 225–50.Google Scholar
Peralta, S. H. 1993. Estratigrafía y consideraciones paleoambientales de los depósitos marino-clásticos eopaleozoicos de la Precordillera Oriental de San Juan. XII Congreso Geológico Argentino y II Congreso de Exploración de Hidrocarburos 1, 128–37.Google Scholar
Peralta, S. & Baldis, B. 1995. Graptolites y trilobites del Ordovícico tardío en el perfil del río de Las Chacritas, Precordillera Central de San Juan, Argentina. Actas del V Congreso Argentino Paleontología y Bioestratigrafía 201–5. Trelew, Argentina.Google Scholar
Peralta, S., Heredia, S. E. & Beresi, M. 1999. Upper Arenig–Lower Llanvirn sequence of the Las Chacritas River, Central Precordillera, San Juan Province, Argentina. In Quo vadis Ordovician? Short papers of the 8th International Symposium on the Ordovician System (eds Raft, P. K. & Atka, F. O.), pp. 123–6. Acta Universitatis Carolinae, Geologica no. 43.Google Scholar
Peralta, S., Pöthe de Baldis, E., León, L. & Pereyra, M. 2003. Silurian of the San Juan Precordillera, western Argentina: stratigraphic framework. In Proceedings of the 7th International Graptolite Conference and Field Meeting of the International Subcommission on Silurian Stratigraphy (eds Ortega, G. & Aceñolaza, F. G.), pp. 151–5. Instituto Superior de Correlación Geológica, San Miguel de Tucuman, Serie Correlaciones Geológicas no. 18.Google Scholar
Pohler, S. M. L. 1994. Conodont biofacies of Lower to lower Middle Ordovician Mega- conglomerates, Cow Head Group, Western Newfoundland. Geological Survey of Canada Bulletin 459, 1–71.Google Scholar
Rasmussen, J. A. & Stouge, S. 1995. Late Arenig–early Llanvirn conodont biofacies across the Iapetus ocean. In Ordovician Odyssey. Short Papers for the Seventh International Symposium on the Ordovician System (eds Cooper, J. D., Droser, M. L. & Finney, S. C.), pp. 443–7. SEPM, Pacific Section, Fullerton, California, Book 77.Google Scholar
Sarmiento, G. N. 1985. La Biozona de Amorphognathus variabilis–Eoplacognathus pseudoplanus (conodonta), Llanvirniano inferior, en el flanco oriental de la sierra de Villicum. Acta de la Primeras Jornadas sobre Geología de la Precordillera, San Juan I, 119–23.Google Scholar
Sarmiento, G. N. 1991. Conodontos de la Zona E. suecicus (Llanvirniano inferior) en la sierra de Villicum, Precordillera de San Juan, Argentina. Revista Española de Micropaleontología 23, 113–32.Google Scholar
Serra, F. & Albanesi, G. L. 2013. Paleoecology and paleobiogeography of Darriwilian conodonts from the Las Chacritas Formation, Central Precordillera of San Juan, Argentina. In Conodonts from the Andes, 3rd International Conodont Symposium (eds Albanesi, G. L. & Ortega, G.), pp. 103–8. Asociación Paleontológica Argentina, Special Publication no. 13.Google Scholar
Serra, F., Albanesi, G. L. & Bergström, S. M. 2013. Middle Darriwilian conodont biostratigraphy of the Las Chacritas Formation, Central Precodrillera of San Juan, Argentina. In Conodonts from the Andes, 3rd International Conodont Symposium (eds Albanesi, G. L. & Ortega, G.), pp. 109–15. Asociación Paleontológica Argentina, Special Publication no. 13.Google Scholar
Stouge, S. 1984. Conodonts of the Middle Ordovician Table Head Formation, western Newfoundland. Fossils and Strata 16, 1–145.Google Scholar
Stouge, S. 2012. Middle Ordovician (late Dapingian–Darriwilian) conodonts from the Cow Head Group and Lower Head Formation, western Newfoundland, Canada. Canadian Journal of Earth Sciences 49 (1), 59–90.Google Scholar
Stouge, S. S. & Nielsen, A. T. 2003. An integrated biostratigraphical analysis of the Volkhov–Kunda (Lower Ordovician) succession at Fågelsång, Scania. Bulletin of the Geological Society of Denmark 50, 75–94.CrossRefGoogle Scholar
Toro, B. A. 1999. Early Ordovician (Arenig) graptolites of northwestern Argentina (Cordillera Oriental and Famatina): Paleogeographic remarks. Acta Universitatis Carolinae, Geologica 43, 437–40.Google Scholar
Toro, B. A. & Brussa, E. D. 2003. Graptolites. In Ordovician Fossils of Argentina (ed. Benedetto, J. L.), pp. 441–505. Secretaría de Ciencia y Tecnología, Universidad Nacional de Córdoba.Google Scholar
Vento, B. A., Toro, B. A. & Maletz, J. 2012. New insights into the paleobiogeography of the Early Ordovician graptolite fauna of northwestern Argentina. Comptes Rendus Palevol 11, 345–55.Google Scholar
Viira, V. 1967. Ordovician conodont succession in the Ohesaare core. Eesti NSV teaduste Akadeemia Toimetised, Keemia Geoloogia 16, 319–29.CrossRefGoogle Scholar
Viira, V. 1974. Ordovician Conodonts of the East Baltic. Tallinn: Valgus.Google Scholar
Webby, B. D., Cooper, R. A., Bergström, S. M. & Paris, F. 2004. Stratigraphic framework and time slices. In The Great Ordovician Biodiversification Event (eds Webby, B. D., Paris, F., Droser, M. L. & Percival, I. G.), pp. 41–47. New York: Columbia University Press.Google Scholar
Zhang, J-H. 1998 a. Conodonts from the Guniutan Formation (Llanvirnian) in Hubei and Hunan Provinces, south-central China. Stockholm Contributions in Geology 46, 1–161.Google Scholar
Zhang, J-H. 1998 b. Middle Ordovician conodonts from the Atlantic Faunal Region and the evolution of key conodont genera. Meddelanden från Stockholms Universitets Institution för Geologi och Geokemi 298, 5–27.Google Scholar
Zhang, J-H. 1998 c. The Ordovician conodont genus Pygodus . In Proceedings of the Sixth European Conodont Symposium (ed. Szaniawski, H.), Palaeontologia Polonica 58, 87–105.Google Scholar
Zhang, J-H. 1999. Review of the Ordovician conodont zonal index Eoplacognathus suecicus Bergström, 1971. Journal of Paleontology 73, 487–93.Google Scholar
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