Los fósiles del Proterozoico Superior y Paleozoico Inferior de Argentina.

J. BENEDETTO, G. ACEÑOLAZA, G. ALBANESI, M. ALFARO, E. BRUSSA, L. BUATOIS, M. CARRERA, N. CECH, S. ESTEBAN, S. HEREDIA, M. MÁNGANO, G. ORTEGA, E. OTTONE, C. RUBINSTEIN, M. SALAS, T. SÁNCHEZ, B.TORO, M. TORTELLO, N. VACCARI Y B. WAISFELD

PUBLICACION ESPECIAL - ASOCIACION PALEONTOLOGICA ARGENTINA

Asociación Paleontológica Argentina

Lugar: Buenos Aires; Año: 2007 vol. 11 p. 9 - 32

0328-347X

This chapter aims to synthesize the current state of knowledge on the Proterozoic and Lower Paleozoic fossils of Argentina. A wide range of taxonomic groups are considered, especially those from marine environments. First, the paleoecological and evolutionary significance of the Vendian-Lower Cambrian ichnofaunas is analyzed in order to understand the early colonization of marine substrate and the role played by the microbial communities in the ecologic structure. Paleoecology of Ordovician faunas has been the focus of numerous studies, both at community and at biofacies scale. Some regional, basin-scale interpretations have also been proposed, mainly in the Lower-Mid Ordovician carbonate platform of the Precordillera basin. Studies on Silurian and Devonian assemblages are still scarce. Comparative studies among different Ordovician basins allowed to recognize different type-assemblages defined on the basis of the overall taxonomic diversity, alpha diversity and ecospace utilization. It is believed that the nature of these assemblages was largely controlled by environmental dynamics at each geodynamic setting coupled with the latitudinal position of the basins. The Evolutionary Faunas model has been critically analyzed from the evidence of Gondwanan assemblages, suggesting that it is not entirely applicable at global scale. Paleobiogeographic analysis of Cambrian and Ordovician faunas from Argentina led to propose that the Precordillera is a Laurentian-derived terrane accreted to Gondwana by the Mid-Late Ordovician. A considerable progress has been madein the biostratigraphic analysis of the rich Lower Paleozoic conodont, graptolite, trilobite and palinomorph assemblages from the Upper Cambrian, Ordovician and Silurian of Argentina, leading to establish accurate biostratigraphic schemas.