Silurian (Llandovery) monograptids from the Vargas Peña Formation (Paraná Basin, Eastern Paraguay)

Authors

  • N.J. URIZ División Geología, Museo de La PlataPaseo del Bosque s/n° 1900, La Plata, Argentina.
  • M.B. ALFARO División Geología, Museo de La PlataPaseo del Bosque s/n° 1900, La Plata, Argentina.
  • J.C. GALEANO INCHAUSTI Ministerio de Obras Públicas y Comunicaciones, Subsecretaria de Minas y EnergíaRepública del Paraguay.

DOI:

https://doi.org/10.1344/105.000000250

Keywords:

Graptolites, Monograptid, Biostratigraphy, Silurian, Paraguay, Gondwana

Abstract

The Itacurubí Group is a siliciclastic Silurian sequence exposed in eastern Paraguay (Paraná Basin). It includes from bottom to top the Eusebio Ayala, Vargas Peña and Cariy formations. The entire sedimentary group has yielded a rich association of invertebrates, ichnofossils and palynomorphs. The low-diversity graptolite fauna found within the uppermost beds of the Vargas Peña Formation is described herein. The monograptids comprising this fauna are Stimulograptus aff. sedgwickii (PORTLOCK), Monograptus aff. priodon (BRONN) and ?Demirastrites sp. These taxa confirm the presence of late Aeronian-early Telychian deposits. The accompanying fossil assemblage also suggests a Mid-Llandovery age for this unit. The recognized graptolite biozones allow us to correlate the Vargas Pena Formation with other Silurian units in South America. From the palaeoenvironmental point of view this sector of the Parana Basin reflects a shallow shelf with high tolerance to oxygen invertebrates association.

References

Albanesi, G.L., Ortega, G., Hünicken M.A., 2006. Bioestratigrafía de conodontes y graptolitos silúricos en la sierra de Talacasto, Precordillera de San Juan, Argentina. Ameghiniana, 43, 93-112.

Barrande, J., 1850. Graptolites de Bohême. vi, 1-74, 4 pl. Prague.

Benedetto, J.L., 2002. The rhynchonellide brachiopod Eocoelia in the Llandovery of Paraguay, Paraná basin. Ameghiniana, 39, 307-312.

Bjerreskov, M., 1975. Llandoverian and Wenlockian graptolites from Bornholm. Fossils and Strata, 8, 1-93.

Bronn, H.G., 1835. Lethaea geognostica. Volume 1. E. Schweizerbart, Stuttgart, 1-768.

Cocks, L.M.R., 1972. The origin of the Silurian Clarkeia Shelly fauna of South America, and its extension to West Africa. Palaeontology 15(4), 623-630.

Diaz-Martínez, E., 1998. Silurian of Perú and Bolivia: recent advances and future research. In: Gutiérrez-Marco, J.C., Rábano, I. (eds.). Sixth international Graptolite Conference, Madrid, Temas Geológicos-mineros, 23, 69-75.

Dyck, M., 1991. Stratigraphie, Fauna, Sedimentologie und Tektonik im Ordoviziun und Silur von ost-Paraguay und vergleich mit den Argentinisch-Bolivianischen Anden. Ph. D. Thesis. Hannover University, 263 pp.

Eisel, R., 1912. Über zonenweise Entwicklung der Rastriten und Demirastriten: Jber. Ges.Freund-Naturw. Gera, 53/54, 27-43.

Elles, G.L., Wood, E.M.R., 1901-1918. Monograph of British Graptolites. Ch. Lapworth (ed.). London, Palaeontology Society of London, Monograph, 91, 539 pp.

Geinitz, H.B., 1852. Die Vertsteinerungen der Grauwacken-Formation (Die graptolithen). Leipzig, Verlag Wilhelm Engelmann, 58 pp.

Gonçalves de Melo, J.H., Boucot, A.J., 1990. Harringtonina is Anabaia (Brachiopoda, Silurian, Malvinokaffric Realm). Journal of Paleontology, 64, 363-366.

Grahn, Y., Pereira, E., Bergamaschi, S., 2000. Silurian and lower Devonian Chitinozoan biostratigraphy of the Paraná Basin in Brazil and Paraguay. Palynology, 24, 147-176.

Harkness, R., 1851. Description of the graptolites found in the Black Shales of Dumfriesshire. Quaternary Journal of the Geological Society of London, 7, 58-65.

Harrington, H.J., 1950. Geología del Paraguay Oriental, Contribuciones Científicas, Serie E: Geología. Facultad de Ciencias Exactas, Física y Naturales, Universidad Buenos Aires, I, 9-80.

Harrington, H.J., 1972. Silurian of Paraguay. In: Berry, W.B.N., Boucot, A.J. (eds.). Correlation of the South American Silurian Rocks. Geological Society of America, Special Paper, 133, 41-50.

Kerlleñevich, S.C., Cuerda, A.J., 1986. Monograptus priodon (Bronn) (Graptolithina) en la Formación La Chilca, Precordillera de San Juan, Argentina. Ameghiniana, 23, 119-126.

Lapworth, C., 1873. On an improved classification of the Rhabdophora. Geological Magazine, 10, 500-504.

Lapworth, C., 1875. Description of graptolites of the Arenig and Llandeilo rocks of St. Davids. Quarterly Journal of Geological Society of London, 31, 631-672.

Lapworth, C., 1876. The Silurian system in the south of Scotland. In, Catalogue of Western Scottish Fossils. Armstrong, J. et al (ed.), 28 pp., 4 pl. Glasgow.

Lapworth, C., 1880. On New British Graptolites. Annals and Magazine of Natural History, 5, 149-177.

Lenz, A.C., 1982. Llandoverian graptolites of the Northen Canadian Cordillera: Petalograptus, Cephalograptus, Rhaphidograptus, Dimorphograptus, Retiolitidea, Monograptidae. Life Sciences Contribution, Royal Ontario Museum, 130, 1-154.

Lenz, A.C., Kozlowska-Dawidziuk, A., 2001. Upper Wenlock (Silurian) graptolites of Arctic Canada: pre-extintion, lundgreni Biozone fauna. Palaeontographica Canadiana, 20, 1-61.

Loydell, D.K., 1993. Upper Aeronian and lower Telychian (Llandovery) graptolites from western mid –Wales. Part 2. Monograph of the Palaeontographical Society, 147(592), 56-180.

M’Coy, F., 1850. On some new genera and species of Silurian Radiata in the collection of the University of Cambridge. Annals and Magazine of Natural History, 6, 270-290.

Mendlowicz Mauller, P., Pereira, E., Grahn, Y., 2004. Análise Bioestratigráfica do intervalo Llandoveriano da Bacia do Paraná no Paraguai Oriental. Revista Brasileira de Paleontologia, 7, 199-212.

Mitchell, C.E., 1987. Evolution and phylogenetic classification of the Diplograptacea. Palaeontology, 30, 353-405.

Nicholson, H.A., 1869. On some new Species of Graptolites. Annals and Magazine of Natural History, London, (4) 4: 231-242.

Perner, J., 1894-9. Études sur les graptolithes de Bohême. Prague: (1), 1894, 1-14, pl. 1.3; (2), 1895, 1-31, pl. 4-8; (3a), 1897, 1-25, pl. 9-13; (3b), 1899, 1-24, pl. 14-17.

Portlock, J.E., 1843. Report on the Geology of the County of Londonderry, and parts of Tyrone and Fermanagh, 21, 748 pp. Dublin and London.

Pribyl, A., Storch, P., 1983. Monograptus (Stimulograptus) subgen. n. (Graptolites) from the Lower Silurian of Bohemia. Vestník Ust ˇ ˇredního Ústavu Geologického 58, 221-224.

Rickards, R.B., 1970. The Llandovery (Silurian) graptolites of the Howgill Fells, Nothern England. Palaentographical Society of London, Monograph, 108 pp.

Rickards, R.B., 1976. Classification of Monograptus: A redefinition of some Llandovery graptolite genera. In: Kaljo, D., Koren, T.N. (eds.). Graptolites and Stratigraphy. Tallinn, Academy of Sciences of Estonia, 155-163.

Rubinstein, C.V., Brussa, E.D., 1999. A palynomorph and graptolite biostratigraphy of the Central Precordillera Silurian Basin, Argentina. Bollettino della Societá Paleontologica Italiana, 38 (2-3), 257-266.

Ruedemann, R., 1947. Graptolites of North America. Geological Society of America Memoir, 19, 1-652.

Sherwin, L., 1974. Llandovery graptolites from the Forbes District, New South Wales. In: Rickards, R.B., Jackson, D.E., Hughes, C.P. (eds.). Graptolites studies in honor of O.M.B. Bulman. London, Special Paper in Palaeontology, 13, 149-175.

Storch, P., 1998. Biostratigraphy, palaeobiogeographical links and environmental interpretation of the Llandovery and Wenlock graptolite fauna of peri-Gondwanan Europe. In: Gutiérrez-Marco, J.C., Rábano, I. (eds.). Sixth International Graptolite Conference, Madrid, Temas Geológicos-Mineros, 23, 126-129.

Storch, P., Serpagli, E., 1993. Lower Silurian Graptolites from Southwestern Sardinia. Bollettino della Società Paleontologica Italiana, 32, 3-57.

Toro, B.A., 1995. Primer hallazgo de Graptolitos del Silúrico (Llandoveriano) en la Cordillera Oriental, Provincia de Jujuy, Argentina. Ameghiniana, 32, 375-384.

Turner, J.C.M., 1960. Fauna graptolitica de América del Sur. Revista de la Asociación Geológica Argentina, 14, 5-180.

Wood, G.D., Miller, M.A., 1991. Distinctive Silurian chitinozoans from the Itacurubí Group (Vargas Peña Shale), Chaco Basin, Paranguay. Palynology, 15, 181-192.

Wood, G.D., Miller, M.A., 1997. Pre-Carboniferous Chlorophyta: New reports of Hydrodictyaceae ? Scenedesmaceae and ? Zygnemataceae. In: Fatka, O., Servais, T. (eds.). Acritarchs in Praha. Actas Carolinae Universiteria, 40, 703-717.

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Published

2009-04-22