The Paltodus deltifer Zone (late Tremadocian; Early Ordovician) in Argentina: new conodont data for intercontinental correlation and paleobiogeographic analysis

ALBANESI, G.L.; ZEBALLO, F.J.; BERGSTRÖM, S.M.

Acta Palaeontologica Sinica

Science Press, Beijing

Año: 2007 vol. 46 p. 16 - 22

0001-6616

The late Tremadocian Paltodus deltifer Zone in the Cuyania terrane, Famatina System, and Eastern Cordillera of northwestern Argentina is analysed in order to provide updated ties for regional and intercontinental correlation across the Iapetus Ocean. The Cuyanian faunas display high similarities with coeval Laurentian faunas although some species typical of the Baltoscandian region are also present. Using high-resolution conodont biostratigraphy, the Baltoscandian P. deltifer Zone is correlated with the middle-upper Rossodus manitouensis Zone, the Low Diversity Interval, and the lower-middle Macerodus dianae Zone of the North American zone scheme. The mixed conodont species assemblage of Famatina contains both Baltic and Laurentian elements. The conodont species associations of the P. deltifer Zone in the Eastern Cordillera allow for recognition of a lower P. d. pristinus Subzone and an upper P. d. deltifer Subzone. The conodont collection of the Eastern Cordillera is the most diverse among those of the Argentine basins, and comprises species typical of both low and high latitude faunas. However, it is dominated by endemic species, which suggests recognition of a new paleobiogeographic unit, the South Gondwana Province of the Cold Domain in the Shallow-Sea Realm.