Bioestratigraphic scheme of marine upper Paleozoic of the Uspallata-Iglesia basin, Argentine Republic

Abstract

?Bioestratigraphic scheme of marine upper Paleozoic of the Uspallata-Iglesia basin, Argentine Republic?. Pacific marine ingressions in Upper Paleozoic sedimentary sequence of western Argentine can be dated. They contain fossil invertebrate of the Protocanites, Levipustula and Cancrinella Zones. Other biozones, provisionally named ?intermediate fauna?, were also recognized between the Levipustula and Cancrinella Zones. A faunal assamblage in Santa Flena Formation, named here informally ?early Eurydesma fauna?, seems to he intermediate between the Cancrinella Zone and the Eurydesma Fauna from the Bonete Formation of eastern Argentina. No paleontological record is known between the Protocanites and Levipustula Zones during most of Visean times. The Carboniferous paleogeographic pattern of western Argentina, as inferred from the distribution of marine invertebrate faunas, is an alternate recurrence of marine environments between northern and southern depositional areas of the Precordillera, This behaviour allows us to define properly the Uspallata-Iglesia Basin, with two different sub-basins: Río Blanco and Calingasta-Uspallata.