Vegetation and Climate in Southern South America during Marine Isotope Stage 3 (MIS 3): an Overview of Existing Terrestrial Pollen Records

A.M. BORROMEI; L.L. MUSOTTO

Marine Isotope Stage 3 in Southern South America, 60 ka B.P.-30 ka B.P.

Springer International Publishing AG

Año: 2016; p. 279 - 298

Data from terrestrial pollen records in the Chilean sector show that Marine Oxygen Isotope Stage 3 (MIS 3) was characterized by the Heinrich (stadials)/Dansgaard-Oeschger (interstadials) oscillations. At central Chile (32-38° S) an open beech/podocarp woodland was apparently established during the last ice age under cold and humid climate, where nowadays grows a semi-arid, broad sclerophyllous vegetation, while episodes of aridity with rise of temperature were indicated by expansion of chenopods-amaranths. At the Southern Lake District and northern Isla Grande de Chiloé (40°-42° 30? S) the stadial events were characterized by higher amounts of grasses indicative of the Subantarctic Parkland vegetation. This vegetation implied summer temperatures of ~6 ºC (~8 ºC below present). The interstadials were represented by expansion of the Valdivian-North Patagonian Evergreen Forest-Subantarctic Evergreen Forest implying summer temperatures of ~12 ºC. In the Argentine sector the steppe environmental conditions prevailed. Interstadial conditions are pointed out at 39º S, in NW Patagonia. Meanwhile, in southern Patagonia at 51º-52º S, and Tierra del Fuego at 54º S, the climate conditions during MIS 3 are interpreted as colder and drier than today.