MÚLTIPLES INDICADORES DE LOS CAMBIOS AMBIENTALES DESDE EL HOLOCENO MEDIO EN EL NORESTE DE PATAGONIA (BAJO DE LA QUINTA), ARGENTINA

Abstract

Paleoecology is a useful tool in the exploration of changes occurring in the environment over time. Particularly, multi-proxy studies provide a more comprehensive picture of climatic conditions in the past. This work is a newcontribution to the available paleoenvironmental information on the northern Patagonian Atlantic coast. It aims to reconstruct the paleoenvironmental history of Bajo de la Quinta (northeasternPatagonia) using pollen, diatoms, organic matter, carbonates and geomorphological studies. The section suggests changes in climate and vegetation occurring since the middleHolocene, revealing an important change from arid tosemiarid conditions during the late Holocene –at 3000 years cal. BP. This may berelated to more frequent contributions of moisture from the Atlantic and a weakening ofthe western winds. These environmental conditions favored the development of the shrub communities known as Monte. Such a development was synchronous with geomorphological changes of the coast, where connection to the sea was interrupted to originate a lagoon. The diatom content suggests the deposit represents a shallow fresh-brackish environment possibly exposed to periodic desiccation. This multi-proxy study improves and complements the current paleoenvironmental offsetting accepted for the northern coast of Río Negro Province.