Are the Oxygen isotopic compositions of Fitzroya cupressoides and Nothofagus pumilio cellulose promising proxies for climate reconstructions in northern Patagonia?

LAVERGNE, A; DAUX, V.; VILLALBA R.; PIERRE, M.; STIEVENARD, M.; VIMEUX, F.; SRUR A.M.

Journal of Geophysical Research: Biogeosciencies

COPERNICUS PUBLICATIONS

Lugar: Gottingen; Año: 2016 vol. 121 p. 767 - 776

Treering δ18Ochronologies from two native species (Fitzroyacupressoides andNothofaguspumilio)in northern Patagonia were developed to assess their potential forpaleoclimate reconstructions. The fiveannually resolved cellulose δ18Ochronologies (two for F.cupressoidesandthree for N.pumilio)are located on the Andes along the steep west-to-east precipitationgradient. Over the common 60 years long interval, the fivesite-δ18Ocellchronologiesexhibit a strong common signal as indicated by the significantmean intercorrelation (r=0.61, p<0.05)and the high percentage (65%) of total variance explained by thefirstempirical orthogonal function. Although correlation analyses revealthat the two mean species-δ18Ocellchronologiesare mainly modulated by December?Maytemperature, the N.pumiliochronologyshows a greater sensitivity to record temperature variations (r=0.57, p<0.05).The δ18OcellofN.pumiliocontainsa regional temperature signal representative of a large area insouthern South America under the influenceof the Southern Annular Mode. This study indicates that δ18OcellinN.pumilioisa promising proxy to reconstruct past variations in temperature inSouth America south of 38°S.