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Climatic variations in the Argentine plains during the last 18,000 years

1993; Elsevier BV; Volume: 101; Issue: 3-4 Linguagem: Inglês

10.1016/0031-0182(93)90013-9

1872-616X

Martíń Iriondo, Norberto O. García,

Pleistocene-Era Hominins and Archaeology

The last deglacial hemicycle was characterized by a general increase in temperature and precipitation in the region, with a few significant departures from this general trend. The present NE-SW climatic gradient was maintained throughout the entire period, except in the Upper Holocene. The following sequence of events is apparent if the present climate is taken as a reference base: (a) 18,000–8500 yr B.P.: Arid and cool, with aeolian sand ad loess deposition. Patagonian fauna. Climatic isolines (temperature, precipitation, etc.) were located some 750 km northeast of their present positions. (b) 8500-3500 yr B.P.: Humid subtropical, with Brazilian fauna. Pedogenesis and fluvial dynamics. Climatic limits migrated about 800/900 km southwest of their former positions. (c) 3500-1000 yr B.P.: Dry subtropical; aeolian dynamics. The normal latitudinal climatic gradient was interrupted by the occurrence of an anticyclonic centre, which stabilized the climate over an area of some 1,600,000 km2. (d) 1000 yr B.P.-Little Ice Age: Climate was similar to the present one over much of the plains, but the northeastern extremity was warmer. (e) Little Ice Age: Climatic deterioration in the southern belt was characterized by generalized aeolian activity and migration of isolines more than 150 km to the northeast in that area. (f) Present climate: 19th and 20th centuries. Subtropical, humid in the east and dry in the west.