Paraná-Paraguay Basin: A review of the geology and the plant fossil record.

BREA M. Y A. F. ZUCOL.

Historical biogeography of Neotropical freshwater fishes.

Verlag Dr. Friedrich Pfeil. Ed. München.

Lugar: Munich; Año: 2009;

This chapter reviews the geological, hydrological, and paleoenvironmental history of the La Plata Basin over the course of the Upper Cretaceous and Cenozoic. The La Plata system in south-eastern South America is one of the world’s great river systems, with geological origins that can be traced to the Mesozoic break up of Gondwana. The principal tributaries are the Paraná, Paraguay and Uruguay rivers. The Paraná-Paraguay fluvial basin is mostly confined to the limits of the Intracratonic sedimentary Paraná Basin. The intracratonic Paraná Basin consists of sedimentary deposits spanning in age from the Paleozoic to the Cenozoic and is covered by extensive basaltic flows of Jurassic-Cretaceous age related to the opening of the South Atlantic Ocean. This chaper describes the paleogeography of the La Plata Basin that is registered in the sedimentary records of the Paraná Intracratonic Basin after the breakup of Gondwana. The main goals are to provide a synthetic chronology of the geological and paleontological history of the region, by examining the plant fossil record in the southernmost Paraná Intracratonic Basin as a basis to compare with the Recent biodiversity. The Argentine Litoral region located in the middle and inferior sectors of this Basin is characterized by a great number of paleobotanical localities. These include Middle Miocene sediments that record a major marine transgression (the Paraná Formation, "Paranense sea”), as well as Plio-Pleistocene sediments of terrestial origin. The use and limits of these fossils in inferring paleoclimatic and paleohabitat data are also discussed. The general patter is one of gradual cooling and drying as the The Argentine Litoral region transitioned from mesic tropical and subtropical climates and dominant plant forms in the Paleogene and Early Miocene to more xeric and temperate climates and associated plant forms in the Plio-Pleistocene to Recent.