pampas

(Spanish term derived from a Quechua Indian word).

(1) The name of several grassy plains in South America. The Pampas proper are a natural region in Argentina extending from 29°–39° S lat. to the Sierra de Córdoba in the west. In the east the pampas are low-lying (30–150 m) with flat sinkholes and ancient valleys. Sandy hills are found in the west, and in the southeast are the Sierra del Tandil and Sierra de la Ventana, rising to 1,250 m. The climate is subtropical, becoming more continental to the west. The average January temperature ranges from 19° to 24°C, and the average July temperature varies from 6° to 10°C. In the east the precipitation falls evenly throughout the year, averaging 800–950 mm annually; the west receives 300–500 mm of rain, falling in summer. Strong southerly winds, called pamperos, are typical.

The region’s main rivers are the Paraná and its tributaries, the Carcaraña and Salado. In the east the Pampas are marshy and crossed by drainage canals; the west has no surface waters, and groundwater is used. The eastern section of the plain was once covered with forb and grassy vegetation growing on reddish black soils (like the prairies of North America). The west was a dry scrub steppe on gray-brown soils. Now the Pampas are cultivated (wheat and corn) or used for pasture. They are Argentina’s main economic region.

(2) Subtropical steppe vegetation growing on plains in the southern part of South America and consisting of grasses and other herbaceous plants. The most typical grasses are meadow grass, feather grass, Aristida, oniongrass, brome, quaking grass, fescue, and koeleria; other common herbaceous plants are campions, sandworts, lupines, vetches, and red verbenas. The family Compositae is represented by ragwort, and there are many plants of the iris, myrtle, and nightshade families. Animals include white-tailed deer, pumas, Pampas cats, armadillos, and vizcachas.