Mid-Holocene climatic variability reconstruction from pollen records (32°–52°S, Argentina)

摘要: Abstract This study reviews 42 published pollen records to gain a better understanding of Holocene climate variability, especially the past displacement and location arid–semiarid region (ASR) between 32° 52°S in Argentina. At present, ASR is delimited approximately 500 mm isohyet Pampa 300 mm Andean sector (south 37°S) represented by arid semiarid types where precipitation can be as low 200 mm. Mid-Holocene climatic variability affected regional vegetation patterns borders ASR. Paleoenvironmental reconstruction based on comparison fossil from different depositional environments. Maps distribution plant formations are reconstructed at 2000±500 year intervals 8000 4000 14 C years BP. Vegetation changes mainly explained position seasonal amplitude latitudinal shifts Pacific Atlantic Anticyclones westerlies. From BP eastern limit was displaced eastward. The western reached maximum eastward southern extreme Patagonia 6000 this time, center ASR, shrub steppes Monte developed, suggesting dry conditions establishment Arid Diagonal north 42°S, while present-day Espinal–Dry ecotone became established. paleodata suggest transitional stage towards present situation