Río de la Plata Lowlands

the name of the low-lying eastern part of the Paraguay and Paraná river plains (the Central Plains) in South America, (east of Gran Chaco and the Pampas and in the interfluvial area). The Río de la Plata Lowlands extend 2,400 km north and south and 900 km east and west; they are a syneclise of the South American platform, filled up by a powerful push of continental, predominantly Cenozoic, deposits. The northern part has sparse woodlands, extensive swamps along the rivers, and a tropical climate with wet summers; the south, made up of prairies and steppes, has a subtropical climate with an even distribution of precipitation during the year.