Review of Palaeobotany and Palynology

MARCOS M.A.; ECHEVERRIA, M.E; SOTTILE, G.; BAMONTE F.P.; MANCINI M.V.

REVIEW OF PALAEOBOTANY AND PALYNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 245 p. 242 - 250

0034-6667

The core of the storm track flow intersects the landmass of Southern Patagonia providing a unique opportunityfor palaeo-reconstructions. Most of the palaeo-reconstructions are based on records from sites where the relationshipbetween precipitation and wind flow intensity, can be reconstructed from the impact on vegetationcommunities. Seven sites were selected for this study. The importance relies on their location in relation to vegetationcommunities; two sites lie within forest communities, two are from the forest-steppe ecotone and theother three from steppe communities in Southern Patagonia, Argentina, between 48° and 52.5° S and between70° and 72° W. To compare the past palaeohydric balance based on the seven pollen records from these differentvegetation communities along the precipitation gradient, we constructed a Palaeohydric Balance Index (PBI). ThePBI is based on thewater requirement of the main plant taxa represented by the pollen types analyzed in the records.The information provided by this index improves the understanding of the hydric balance variability in relationto the storm track behavior. During the last 8000 cal yrs BP we observed out-of-phase behavior in PBIvariations between forest, forest-steppe ecotone and steppe PBIs, a greater amplitude of forest versus steppe environmentsand low amplitude of the forest-steppe ecotone variability. This out-of-phase behavior appears tohave been replaced by in-phase palaeohydric changes between 700 and 500 cal yrs BP interpreted as relatedto an equatorward migration of the storm tracks.